A phylogenetic analysis of 14 genera of the family Goneplacidae MacLeay (Decapoda: Brachyura: Xanthoidea) is presented based upon 45 adult morphological characters. Two most-parsimonious trees were obtained (length = 87, CI = 0.6667, RI = 0.8242, RC = 0.5495). The present analysis suggests that the Goneplacidae is divided into six subfamilies: Carinocarcinoidinae subfam. nov., Chasmocarcininae Serène, Euryplacinae Stimpson, Goneplacinae MacLeay, Mathildellinae subfam. nov., and Trogloplacinae Guinot. The Carcinoplacinae H. Milne Edwards is synonymised with the Goneplacinae. The family and six subfamilies are defined or redefined based upon the phylogenetic analysis. Within the Goneplacidae, the Trogloplacinae and Chasmocarcininae are sister groups nested as the most derived clade, followed by the Carinocarcinoidinae, Goneplacinae, Euryplacinae, and the most basal Mathildellinae. Our analysis supports recognition of the family Pseudoziidae Alcock by Ng and Liao and suggests that it is the sister to the Eriphiidae MacLeay. A reexamination of fossil records of the Goneplacidae shows that 62 species, 20 genera, and five subfamilies are recognized as fossils. A new monotypic genus Viaplax (Euryplacinae) is erected for Pilumnoplax urpiniana Via. Chlinocephalus Ristori and Gillcarcinus Collins and Morris are moved to the Goneplacidae. Paleopsopheticus Hu and Tao is synonymised with Psopheticus Wood-Mason. Glaessneria Takeda and Miyake is here the junior synonym of Goneplax. Eleven extinct genera previously assigned to the Goneplacidae are not referred to any subfamilies and are transferred out of the Goneplacidae. New combinations include: Carcinoplax proavita (Glaessner), Goneplax arenicola (Glaessner), Euphylax zariquieri (Via) (Portunidae Rafinesque), and Psopheticus shujienae (Hu and Tao).
Introduction
The family Goneplacidae MacLeay, 1838 (Brachyura: Heterotremata: Xanthoidea) has been traditionally recognized as a monophyletic group containing the five subfamilies, Carcinoplacinae H. Milne Edwards, 1852, Eucratopsinae Stimpson, 1871 (= Prionoplacinae Alcock, 1900), Goneplacinae MacLeay, 1838, Hexapodinae Miers, 1886, and Rhizopinae Stimpson, 1858 (Balss, 1957; Sakai, 1976). Guinot (1969a) suggested that the Goneplacidae sensu Balss (1957) was a polyphyletic group and first divided the Goneplacidae into three major groups; “Goneplacidae dérives des Xanthidae”, “Goneplacidae euryplaciens (Euryplacinae)”, and “Goneplacidae carcinoplaciens-gonéplaciens (Carcinoplacinae + Goneplacinae)”. The subfamily Rhizopinae was removed to the Pilumnidae Samouelle, 1819 (Guinot, 1969c, 1978; Ng, 1987; Davie and Guinot, 1996), the Eucratopsinae was assigned to the Panopeidae Ortmann, 1893 (Guinot, 1978; Martin and Abele, 1986) and the Hexapodinae was treated as a family (Guinot, 1978; Manning and Holthuis, 1981). After Balss's (1957) work, two new subfamilies, Chasmocarcininae Serène, 1964 and Trogloplacinae Guinot, 1986, were added to the family. Ng and Wang (1994) moved the Pseudoziinae Alcock, 1898, from the Eriphiidae MacLeay, 1838, to the Goneplacidae. Therefore, the Goneplacidae is now represented by six subfamilies (Lemaitre et al., 2001; Hsueh and Huang, 2002). Subsequently, Ng and Liao (2002) treated the Pseudoziinae as a distinct family.
Glaessner (1969) recognized 20 genera of die Goneplacidae as fossils and assigned 11 extinct genera to the family. Since then, 12 extinct genera have been added:
Caprocancer Müller and Collins, 1991a; Corallicarcinus Müller and Collins, 1991a; Carinocarcinoides Karasawa and Fudouji, 2000; Chumaoia Hu and Tao, 1996; Orthakrolophos Schweitzer and Feldmann, 2001a; Eoplax Müller and Collins, 1991a; Lobogalenopsis Müller and Collins, 1991a; Orbitoplax Tucker and Feldmann, 1990; Paleopsopheticus Hu and Tao, 1996; Paracorallicarcinus Tessier et al., 1999; Pregeryona Hu and Tao, 1996; and Stoaplax Vega et al., 2001. Karasawa and Kato (2001) moved two extinct genera, Maingrapsus Tessier et al., 1999 and Palaeograpsus Bittner, 1875, from the Grapsidae MacLeay, 1838, to the Goneplacidae. They also referred Telphusograpsus Lörenthey, 1902, to the family. Among these, Carinocarcinoides and Stoaplax were referred to the Carcinoplacinae (Karasawa and Fudouji, 2000; Vega et al., 2001), Orbitoplax to the Euryplacinae (Tucker and Feldmann, 1990), and Orthakrolophos to the Chasmocarcininae (Schweitzer and Feldmann, 2001a). Remaining genera were not assigned to any subfamiles within the Goneplacidae because most genera were represented by only carapace specimens. Distinction between the goneplacid genera, and panopeid, pilumnid, and pseudorhombilid genera is difficult based solely upon carapace characters (Schweitzer, 2000).
The first aim of this paper is to provide an adultmorphology-based phylogenetic analysis for 14 genera within the Goneplacidae. A new classification and diagnoses of six subfamilies are presented based upon the phylogenetic analysis. The second aim of this paper is to review fossil taxa previously assigned to the family. All known fossil species and genera within the Goneplacidae are listed.
Materials and methods
Fourteen genera including one extinct genus, Carinocarcinoides, within the Goneplacidae, were examined. The analysis also includes Epixanthus Heller, 1861 (Eriphiidae MacLeay, 1838: Oziinae Dana, 1851), Pilumnus Leach, 1815 (Pilumnidae Samouelle, 1819: Pilumninae Samouelle, 1819), and Pseudozius Dana, 1851 (Pseudoziidae Alcock, 1898: Pseudoziinae Alcock, 1898) as ingroup taxa to analyze a sister-group relationship of the Goneplacidae. The analyses were based upon the examination of material deposited in the Kanagawa Prefectural Museum of Natural History, Odawara, Japan; the Mizunami Fossil Museum, Mizunami, Japan; the Natural History Museum and Institute, Chiba, Japan; and the National Museum of Natural History, Smithsonian Institution, Washington D.C., U.S.A. The material examined is listed in Table 1. If material was unavailable, the descriptive information of taxa was obtained from the literature. The subfamilial arrangement of the genera conforms to Guinot (1970 [1971]), Guinot and Richer de Forges (1981), Serène (1984), Davie and Guinot (1996), Karasawa and Fudouji (2000), and Ng and Liao (2002).
Table 1
Taxa included in the analysis. Abbreviations: CBM, Natural History Museum and Institute, Chiba; KPM, Kanagawa Prefectural Museum of Natural History; MFM, Mizunami Fossil Museum; NMNH, National Museum of Natural History, Smithsonian Institution; *1, Guinot (1989); *2, Guinot (1990); *3, Ikeda (1998), *4, Rathbun (1918); *5, Felder and Rabalais (1986); *6, Guinot (1986); *7, Guinot and Richer de Forges (1981).
An outgroup was chosen to polarize the character states. The Goneplacidae does not have a reliable sister group. Ortmann (1893) thought that the Goneplacidae (= his Carcinoplacidae + Goneplacidae) were derived from the Eriphiidae (= his Menippidae). Guinot (1969c) and Stevcic in Martin and Davis (2001) mentioned that there is a close relationship between the Goneplacidae and Geryonidae Colosi, 1923 based upon adult morphology. Rice (1980) and Martin (1984) showed that the family is most similar to the Pilumnidae based upon zoeal morphology. Von Sternberg and Cumberlidge (2001) suggested based upon cladistic and phenetic analysis that the Goneplacidae may be more closely related to the Portunidae Rafinesque, 1815, than to any families of the Xanthoidea. Therefore, the cladogram was rooted against a “hypothetical ancestor”. Table 2 lists 45 adult morphological characters and character states used in the analysis. The missing data were scored as unknown. The data matrix is provided in Table 3. Forty-five characters were included in the data matrix (Table 3). There are 42 binary characters and three multistate characters. In the text, characters and character states are indicated by numbers in parentheses (e.g., 1-0 = character 1 + character state 0).
Table 2
Characters and their states used in the phylogenetic analysis.
Table 3
Input data matrix of 45 characters and 17 genera. Missing character states are shown by?.
The phylogenetic analysis used PAUP* 4.0b (Swofford, 1999), utilizing a data matrix originating in MacClade version 4.03 (Maddison and Maddison, 2001). Heuristic search analyses were performed with the following options in effect: addition sequence, 100 replications with random input order; one tree held at each step during stepwise addition; tree-bisection-reconnection (TBR) branch stepping performed; MulTrees option activated; steepest descent option not in effect; branches having maximum length zero collapsed to yield polytomies; topological constraints not enforced; tree unrooted; multistate taxa interpreted as polymorphism; character state optimization; and accelerated transformation (ACCTRAN). All characters were unordered, unsealed and equally weighted. Relative stability of clades was assessed using bootstrap (Felsenstein, 1985) and decay analyses (Bremer, 1994). The bootstrapping was based on 100 replicates of random input order. The Bremer support was obtained using constraint trees generated by AutoDecay 4.02 (Eriksson, 1999) and analyzed using PAUP*.
Results
The present analysis yielded two most-parsimonious trees, 87 steps long with a consistency index (CI) of 0.6667, a retention index (RI) of 0.8242 and a rescaled consistency index (RC) of 0.5495. A strict consensus tree of two most-parsimonious trees, indicating bootstrap and Bremer support, is given in Figure 1. Fourteen distinct clades are recognized. Each clade is numbered with character state changes in Figure 2.
Figure 1
Strict consensus tree of two most-parsimonious trees of 14 genera within the Goneplacidae. Length = 87, Consistency index = 0.6667, Retention index = 0.8242, Rescaled consistency index = 0.5495. Numbers above branches are Bootstrap support and numbers below branches are Bremer support.
Figure 2
Strict consensus tree of two most-parsimonious trees of 14 genera within the Goneplacidae. Length = 87, Consistency index = 0.6667, Retention index = 0.8242, Rescaled consistency index = 0.5495. Character changes are indicated. Numbers above branches are clade numbers.
Clade 1:
Epixanthus + Pseudozius (Eriphiidae + Pseudoziidae). In the examined material Pseudozius and Epixanthus are sister taxa nested as the most basal clade. This clade, with 65% bootstrap support and Bremer support of 2, is united by three synapomorphies (6-1, 7-1, 32-1). None is unique.
Clade 2:
Pilumnus + Goneplacidae. Pilumnus and taxa of the Goneplacidae clade, with 69% bootstrap support and Bremer index of 2, share four synapomorphies, two of which are unique and never reversed: the absence of frontal teeth (3-1) and the absence of a median sulcus on the thoracic sternite 4 (24-1).
Clade 3:
Goneplacidae. The monophyly of the Goneplacidae, with 77% bootstrap support and Bremer index of 3, is well defined by seven synapomorphies, three of which are unique and unreversed: a wide thoracic sternum (21-1), a medially interrupted sulcus delimiting thoracic sternites 6 and 7 (22-1), and long meri of pereiopods 2–5 (42-1).
Clade 4:
Mathildella + Beuroisia + Intesius (Goneplacidae incertae sedis). The Mathildella + Beuroisia + Intesius clade, with 93% bootstrap support and Bremer support of 3, is unambiguously united by four synapomorphies: laterally broad antennular fossae (10-1), the absence of a prolongation of the thoracic sternite 7 in male (26-0; reversal), a strongly inflated basal part of male gonopod 1 (35-1), and a spatulate dactylus of pereiopods 5 (44-1). Two synapomorphies (10-1, 35-1) are unique and never reversed.
Clade 5:
Mathildella + Beuroisia. Only one unique synapomorphy, a semicircular male telson (15-1), defines this clade.
Clade 6:
Euryplacinae + Carcinoplacinae + Goneplacinae + Carinocarcinoides + Trogloplacinae + Chasmocarcininae. This clade, with 85% bootstrap support and Bremer support of 2, shares eight synapomorphies, four of which are unique and never reversed: a medially interrupted sulcus delimiting thoracic sternites 7 and 8 (23-1), an anterior margin of the male sterno-abdominal cavity reaching the anterior part of the thoracic sternite 4 (25-1), the absence of dark-colored cheliped fingers (40-1) and the possession of dactyli of pereiopods 2–5 which terminate with acute chitinous tips (43-1).
Clade 7:
Eucrate + Euryplax + Heteroplax (Euryplacinae). The Euryplacinae clade has 76% bootstrap support and Bremer support of 2. Seven synapomorphies (5-2, 11-0, 14-1, 16-1, 31-1, 36-1, 37-1) well define this clade. A unique synapomorphy is distinctly narrow male abdominal somites 4-6 (16-1). One synapomorphy, the presence of the basal article of antenna reaching the front (11-0), is a reversal.
Clade 9:
Carcinoplacinae + Goneplacinae + Carinocarcinoides + Trogloplacinae + Chasmocarcininae. This clade, with 80% bootstrap support and Bremer index of 2, shares four synapomorphies: the supraorbital angle fused to the frontal margin (4-1), the absence of upper orbital fissures (6-1), a sinuous gonopod 1 (32-0; reversal), and the absence of marginal setae of dactyli of pereiopods 5 (45-0; reversal). The supraorbital angle fused to the frontal margin (4-1) is a unique synapomorphy.
Clade 10:
Psopheticus + Carcinoplax + Ommatocarcinus + Goneplax (Carcinoplacinae + Goneplacinae). The Carcinoplacinae + Goneplacinae clade, with 72% bootstrap support and Bremer index of 2, is well defined by three synapomorphies, two of which are unique: the absence of a median notch on the frontal margin (1-1), and a truncated apex of gonopod 1 (34-1) and the possession of a ventral spine of the cheliped carpus (41-1). The sister-group relationship of the clade (Psopheticus, Carcinoplax and Ommatocarcinus + Goneplax) remained unresolved.
Clade 11:
Ommatocarcinus + Goneplax (Goneplacinae). Five synapomorphies support this clade. Only one synapomorphy, the possession of the front with a median projection (2-1), is unique. Two synapomorphies, the male abdominal somite 2, which is much narrower than somite 3 (18-0), and the absence of a ventral spine of the carpus of the cheliped (41-0), are reversals.
Clade 12:
Carinocarcinoides + Trogloplacinae + Chasmocarcininae. This clade, with 91% bootstrap support and Bremer index of 3, shares three unique synapomorphies: the possession of fused male abdominal somites 3–5 (20-1), the thoracic sternite 8 overlying posterolaterally sternite 7 (27-1), and the thoracic sternite 8 which is visible ventrally (29-1).
Clade 13:
Trogloplacinae + Chasmocarcininae. The Trogloplacinae + Chasmocarcininae clade, with 88% boot-strap support and Bremer support of 5, is evidently united by five synapomorphies (5-0, 8-2, 12-1, 17-1, 18-0, 28-1). Three of these synapomorphies, the presence of maxilliped 3 ischium about equal to merus (12-1), male abdominal somite 3 much narrower than thoracic sternites 7 and 8 (17-1), and the presence of a supplementary plate of male thoracic sternite 8 (27-1), are unique.
Clade 14:
Camatopsis + Chasmocarcinus (Chasmocarcininae). This clade, with 96% bootstrap support and Bremer support of 3, is well defined by four synapomorphies (13-1, 37-1, 44-2, 45-0). The possession of a suboval merus of maxilliped 3 (13-1) is a unique synapomorphy.
Discussion
Guinot (1969a, b, c; 1970 [1971]) divided the family Goneplacidae sensu Balss (1957) into three major groups; “Goneplacidae dérives des Xanthidae”, “Goneplacidae euryplaciens (Euryplacinae)”, and “Goneplacidae carcinoplaciens-gonéplaciens (Carcinoplacinae + Goneplacinae)”. Glaessner (1969) and Sakai (1976) used the classification of the Goneplacidae sensu Balss, while Serène and Soh (1976), Manning and Holthuis (1981), and Williams (1984) partly accepted Guinot's concept for the classification of the family.
Since then, genera belonging to her “Goneplacidae dérives des Xanthidae” were removed to other families. Guinot (1978) and Martin and Abele (1986) transferred the Eucratopsinae to the family Panopeidae. The Rhizopinae sensu lato is currently placed in the Pilumnidae (Guinot, 1969c, 1978; Ng, 1987; Davie and Guinot, 1996). Litocheira Kinaham, 1856 sensu stricto (see Guinot, 1970 [1971]; Türkay, 1975), is referred to her “Goneplacidae pilumniens sensu stricto”, while the genus has not been assigned to any of the pilumnid subfamilies. Guinot (1969c, 1970 [1971]) referred Galene De Haan, 1833, to her “Goneplacidae pilumniens sensu lato”, while Takeda (1976) included the genus within the subfamily Galeninae Alcock, 1898, of the Xanthidae sensu lato. Ng (1998) and Schweitzer (2000) classified Galene within the Pilumnidae, following Guinot (1969c, 1970 [1971]); therefore, species of the Galeninae are thought to be members of the Pilumnidae (Ng et al., 2001; Hsueh and Huang, 2002). The Pseudorhombilinae Alcock, 1900, previously referred to the Goneplacidae, was also included in her “Goneplacidae dérives des Xanthidae” but Hendrickx (1998) treated it as a distinct family.
Davie and Guinot (1996) indicated that the Goneplacidae contains five subfamilies, Goneplacinae MacLeay, Carcinoplacinae H. Milne Edwards, Chasmocarcininae Serène, Trogloplacinae Guinot and Euryplacinae Stimpson. Ng and Wang (1994) transferred the Pseudoziinae Alcock from the Eriphiidae to the Goneplacidae. Therefore, Lemaitre et al., (2001) and Hsueh and Huang (2002) currently divided the Goneplacidae into six subfamilies. Subsequently, Ng and Liao (2002) excluded the Pseudoziinae from the Goneplacidae and treated it as a distinct family.
The present phylogenetic analysis well supports the monophyly of the Goneplacidae as envisioned by Davie and Guinot (1996). Six synapomorphies, three of which are unique and unreversed, well define the Goneplacidae (Figure 2, Clade 3). The present analysis suggests that the Intesius + Mathildella + Beuroisia (Goneplacidae incertae sedis) clade within the Goneplacidae is the most basal, followed by the Euryplacinae, the Carcinoplacinae + Goneplacinae, and the most advanced clade, Carinocarcinoides + Trogloplacinae + Chasmocarcininae.
Pseudozius, the type genus of the Pseudoziidae, is the sister to Epixanthus (Eriphiidae; Oziinae) (Figure 2; clade 1) and both genera are united by three synapomorphies. Alcock (1898) originally placed Pseudozius within his alliance Pseudozioida Alcock (= Pseudoziinae Alcock; nom. transl. of Takeda (1976)) within his Menippinae of the family Xanthidae sensu lato and subsequent workers (i.e., Guinot, 1970[1971]; Sakai, 1976; Takeda, 1976) also placed it within the Xanthidae sensu lato. Crosnier in Serène (1984) referred Pseudozius to incertae sedis within the Menippidae (= Eriphiidae). Ng and Wang (1995) moved the subfamily from the Eriphiidae to the Goneplacidae. Subsequently, Ng and Liao (2002) recognized the Pseudoziinae as a separate family and divided it into two subfamilies, Pseudoziinae and Planopilumninae Serène, 1984. In their work the Pseudoziinae contains four genera, Euryozius Miers, 1886, Flindersoplax Davie, 1989, Platychelonion Crosnier and Guinot, 1969, and Pseudozius, and the Planopilumninae is a monotypic subfamily. Our analysis supports the recognition of the Pseudoziidae by Ng and Liao (2002) and suggests that the family is the sister taxon of the Eriphiidae. Members of the subfamilies Eriphiinae, Oziinae, Menippinae Ortmann, 1893, and Dacryopilumninae Serène, 1984, within the Eriphiidae have a long gonopod 2 with a filamentous, long flagellum (36-0, 37-0, 38-1) while Pseudozius is characterized by having a short gonopod 2 and by lacking a filamentous, long flagellum of gonopod 2 (36-1, 37-1, 38-0).
The most basal Intesius + Mathildella + Beuroisia clade shares four synapomorphies, two of which are unique and never reversed: laterally broad antennular fossae (10-1) and a strongly inflated basal part of gonopod 1 (35-1) (Figure 2; clade 4). The subfamilial placement of three genera has not been well documented. Guinot and Richer de Forges (1981) erected two new genera, Mathildella and Beuroisia, based upon examination of new material and species previously assigned to Neopilumnoplax Serène in Guinot, 1969c, but did not designate subfamilial placement for Mathildella and Beuroisia or for another new genus, Intesius. Guinot (1970 [1971]) placed Neopilumnoplax within “Autres Carcinoplacinae-Goneplacinae” of the Goneplacidae, whereas Sakai (1976) placed it within the Carcinoplacinae. Poupin (1996) assigned Intesius to the Goneplacidae, and Beuroisia and Mathildella to “Xanthoidea incertae sedis”. Ng et al. (2001) and Hsueh and Huang (2002) placed Mathildella within the Carcinoplacinae. The present analysis supports that these three genera should be included within the Goneplacidae. The three genera within this clade differ significantly from other goneplacid genera (Figure 2; clade 6) because they lack the diagnostic synapomorphies of clade 6; therefore, they cannot be placed within previously known subfamilies. A new subfamily, Mathildellinae, is erected herein for these genera.
Several workers did not recognize the Euryplacinae as a valid taxon. Indeed, Balss (1957) included Eucrate and Heteroplax within the Carcinoplacinae, and Euryplax within the Prionoplacinae, and Sakai (1976) classified Eucrate and Heteroplax within the Carcinoplacinae. However, the Euryplacinae (Figure 2, Clade 7) is well supported as monophyletic by seven synapomorphies, one of which is unique and never reversed, distinctly narrow male abdominal somites 4-6 (16-1). The present analysis strongly supports recognition of the subfamily by Guinot (1969a, b, c, 1970 [1971]), Manning and Holthuis (1981), Ng et al. (2001), and Hsueh and Huang (2002). The Euryplacinae clade is the sister to the Carcinoplacinae + Goneplacinae + Carinocarcinoides + Trogloplacinae + Chasmocarcininae clade (Figure 2, Clade 9).
For the Carcinoplacinae, represented by Psopheticus and Carcinoplax, the analysis is unable to resolve the relationships between both taxa and other goneplacines, since they nest in a polytomy with the Goneplacinae clade (Figure 2, Clade 10). In one of the two most-parsimonious trees the subfamily is monophyletic whereas in another tree it is paraphyletic. The monophyly of the Goneplacinae is supported by five synapomorphies, but it is nested among the goneplacine genera (Figure 2, Clade 11). The Carcinoplacinae should either be synonymised with the Goneplacinae or divided into three subfamiles. In the latter scheme, a new monotypic subfamily would have to be proposed for Psopheticus. The Goneplacinae clade with Bremer support of 1 is more weakly defined than the Carcinoplacinae + Goneplacinae clade with Bremer support of 2. In the present analysis the Carcinoplacinae + Goneplacinae clade shares three synapomorphies, two of which are unique: the absence of a median notch on the frontal margin (1-1), and a truncated apex of gonopod 1 (34-1). Therefore, rather than proposing three subfamilies, each with weakly defined synapomorphies and with weak Bremer support, it is considered best to place Carcinoplax and Psopheticus, previously assigned to the Carcinoplacinae, within the Goneplacinae. Our phylogenetic analysis supports Guinot's concept of a “lignée Carcinoplacienne-Gonéplacienne” and “groupement Carcinoplax - Psopheticus - Goneplax - Ommatocarcinus” (Guinot, 1969b, c).
The Carinocarcinoides + Trogloplacinae + Chasmocarcininae clade is characterized by three unique synapomorphies: fused male abdominal somites 3–5 (20-1), thoracic sternite 8 overlying posterolaterally sternite 7 (27-1), and thoracic sternite 8 visible ventrally (29-1) (Figure 2, Clade 12). Karasawa and Fudouji (2000) originally placed Carinocarcinoides within the Carcinoplacinae; however, the present analysis suggests that the genus does not belong to the Carcinoplacinae. Carinocarcinoides is the first to diverge within the clade, characterized by having more or less defined dorsal regions of the carapace (7-0) and elongate chelipeds (39-1). The Trogloplacinae + Chasmocarcininae clade is unambiguously united by six synapomorphies, three of which are unique: ischium of maxilliped 3 about equal to merus (12-1), male abdominal somite 3 much narrower than thoracic sternites 7 and 8 (17-1), and the possession of the supplementary plate of thoracic sternite 8 in males (27-1) (Figure 2, Clade 13). On the basis of the phylogenetic analysis, Carinocarcinoides cannot be included in either subfamily, since it lacks their diagnostic synapomorphies, and the genus is here recognized as the type of a new monotypic subfamily, Carinocarcinoidinae.
The Trogloplacinae is here derived as the sister group to the Chasmocarcininae (Figure 2, Clade 14). Davie and Guinot (1996) suggested that the Trogloplacinae had close affinities with the Chasmocarcininae. We concur. The Trogloplacinae is a weakly defined subfamily lacking the diagnostic synapomorphies of the Chasmocarcininae. The Chasmocarcininae is a distinctive subfamily clearly defined by four autapomorphies (13-1, 37-1, 44-1, 45-1), one of which is unique: the possession of a suboval merus of maxilliped 3 (13-1).
Systematics
Family Goneplacidae MacLeay, 1838 emend.
Diagnosis.
Carapace transversely rectangular, trapezoidal or rounded; dorsal regions weakly distinct or indistinct; front straight, sometimes bearing median notch or median projection, without teeth; notch between frontal and supraorbital angle present or absent; upper orbital margin with or without fissures; anterolateral margin usually toothed; inner antennular septum a thin plate; buccal frame quadrangular; epistome well defined; palp of maxilliped 3 articulating on or near anteromesial corner of merus; exopod wide; male abdomen with all free somites or fused somites 3–5; thoracic sternum wide with all sutures interrupted, rarely with continuous suture delimiting sternites 7 and 8; sternite 4 lacking median sulcus; sternite 7 usually with posterolateral prolongation; chelipeds heterochelate; pereiopods 2–5 long; dactyli of pereiopods 2–5 with or without corneous tips; male genital openings coxal; gonopod 1 stout, sinuous or curved, usually with simple apex; gonopod 2 long or short.
Subfamilies included.
Carinocarcinoidinae subfam. nov.; Chasmocarcininae Serène, 1964; Euryplacinae Stimpson, 1871; Goneplacinae MacLeay, 1838; Mathildellinae subfam. nov.; Trogloplacinae Guinot, 1986.
Subfamily Mathildellinae subfam. nov.
Diagnosis.
Carapace usually flattened with weakly defined dorsal regions; front straight with shallow median notch; supraorbital angle separated from frontal margin; orbit relatively small with upper orbital fissures; anterolateral margin bearing five teeth; eye stalk short; antennular fossae broad laterally; merus of maxilliped 3 subquadrate, much longer than ischium; male abdomen filling entire space between coxae of pereiopods 5, usually with all free somites; thoracic sternum wide with interrupted sutures excluding continuous suture delimiting sternites 7 and 8; sternite 7 without posterolateral prolongation; sterno-abdominal cavity reaching posterior of sternite 4; chelipeds with dark-colored fingers; dactyli of pereiopods 2–5 with corneous tips; dactyli of pereiopods 5 spatulate with setae; gonopod 1 stout, curved, strongly inflated basally, with simple apex; gonopod 2 usually long with long flagellum.
Genera included.
Beuroisia Guinot and Richer de Forges, 1981; Branchioplax Rathbun, 1916; Intesius Guinot and Richer de Forges, 1981; Mathildella; Neopilumnoplax Serène in Guinot, 1969; Platypilumnus Alcock, 1894; Tehuacana Stenzel, 1944.
Discussion.
The Mathildellinae is the most basal group within the Goneplacidae based upon the present phylogenetic analysis. The subfamily is well defined by the presence of more or less defined anterior dorsal regions, laterally broad antennular fossae, a complete sulcus delimiting thoracic sternites 7 and 8, an anterior end of the sterno-abdominal cavity located on the posterior half of the thoracic sternite 4, the absence of a posterolateral prolongation of the thoracic sternite 7, the presence of dark-colored cheliped fingers, dactyli of pereiopods 2–5 with corneous tips, and a strongly inflated basal part of gonopod 1, all of which other goneplacid subfamilies lack.
Alcock (1900) questionably referred Platypilumnus to the Goneplacidae. Guinot (1970 [1971]) placed Platypilumnus within the Geryonidae, while Manning and Holthuis (1989) did not include the genus within the Geryonidae. Richer de Forges (1996) showed that Platypilumnus has close affinities with Neopilumnoplax and Intesius. We concur. Crosnier and Guinot (1969) suggested that Platychelonion is similar to Neopilumnoplax whereas Guinot (1970 [1971]) questionably referred it to the Geryonidae. Manning and Holthuis (1989) excluded the genus from the Geryonidae and Davie (1989) suggested that the genus bears a close resemblance to the Goneplacidae. We place Platychelonion within the Pseudoziidae, following Ng and Liao (2002).
Tucker and Feldmann (1990), Schweitzer et al. (2000), and Schweitzer (2000) described well preserved specimens of Branchioplax washingtoniana Rathbun, 1916, the type species of Branchioplax, from Palaeogene rocks of the U.S.A. In her taxonomic review of Branchioplax Schweitzer (2000) synonymised Pilumnoplax hannibalanus Rathbun, 1926, with B. washingtoniana and moved Pilumnoplax carmanahensis Rathbun, 1926, to Branchioplax. Balss (1957) and Glaessner (1969) referred Branchioplax to the Carcinoplacinae, while Schweitzer (2000) suggested that the genus is similar to the extant Chacellus Guinot, 1969c. Chacellus is now placed within the family Pseudorhombilidae (Hendrickx, 1998). Examination of illustrations of B. washingtoniana and B. pentagonalis (Yokoyama, 1911) indicates that the genus belongs to the Mathildellinae. In Branchioplax the anterior dorsal regions are more or less defined; a nearly straight frontal margin bears a median notch; the supraorbital angle is developed; the upper orbital margin possesses two fissures; the anterior end of the sterno-abdominal cavity located on the posterior part of sternite 4; the sulcus delimiting thoracic sternites 7 and 8 is complete; the posterolaterally directed prolongation of thoracic sternite 7 is not developed; and the male abdomen consists of seven free somites. These characters are also definitive characters of the sub-family.
Stenzel (1944) established the monotypic genus Tehuacana based upon a male specimen from the Palaeogene of the U.S.A. and compared this new genus with “Pilumnoplax Stimpson, 1858”. This genus has upper orbital fissures and more or less defined anterior dorsal regions, and lacks a prolongation of thoracic sternite 7. Therefore, the genus is here assigned to the Mathildellinae.
Fossil records.
Fossil records of the Mathildellinae are represented by two extinct genera known from the Palaeogene (Table 4).
Table 4
Distributions and geologic ranges of recognized fossil species of the subfamily Mathildellinae.
Subfamily Euryplacinae Stimpson, 1871 emend.
Diagnosis.
Carapace usually with poorly defined dorsal regions; front straight with shallow median notch; supraorbital angle distinct; orbit sometimes deep, large, with upper orbital fissures; anterolateral margin bearing two to five spines; eye stalk short or long; basal article of antenna reaching front; merus of maxilliped 3 subquadrate, much longer than ischium; male abdomen filling entire space between coxae of pereiopods 5, with all free somites; somites 4–6 much narrower than somite 3; telson usually longer than wide; thoracic sternum wide with sutures all interrupted; sternite 7 with posterolateral prolongation; sternite 8 visible in posterior view; sterno-abdominal cavity reaching anterior of sternite 4; chelipeds without darkcolored fingers; dactyli of pereiopods 2–5 without corneous tips; dactyli of pereiopods 5 usually styliform, with or without setae; gonopod 1 stout, curved, with simple apex; gonopod 2 very short with short flagellum.
Genera included.
Chlinocephalus Ristori, 1886; Corallicarcinus Müller and Collins, 1991a; Euryplax; Eucrate De Haan, 1835; Fravillea A. Milne Edwards, 1880; Heteroplax Stimpson, 1858; Machaerus Leach, 1818; Nancyplax Lemaitre et al., 2001; Orbitoplax Tucker and Feldmann, 1990; Psopheticoides Sasaki, 1969; Stoaplax Vega et al., 2001; Trizocarcinus Rathbun, 1914; Viaplax gen. nov.
Discussion.
Balss (1957) and Sakai (1976) placed members of the subfamily within the Carcinoplacinae, while Guinot (1970 [1971]), Serène and Soh (1976), Manning and Holthuis (1981), Williams (1984), Ng et al. (2001), and Hsueh and Huang (2002) indicated that the Euryplacinae is a valid taxon. The present analysis strongly supports the monophyly of the Euryplacinae.
Ristori (1886) described a new genus and species, Chlinocephalus demissifrons, from the Pliocene of Italy and originally placed it within the Cancridae Latreille, 1802. Glaessner (1929) referred Chlinocephalus to the Goneplacidae and in 1969 removed the genus to the Xanthidae sensu lato. The genus is reassigned to the Euryplacinae because the male abdomen consists of seven free somites, the telson of the male abdomen is much longer than wide, and the abdominal somites 4 and 5 are much narrower than the somite 3. The genus may resemble Eucrate, but differs by the presence of transverse ridges of the dorsal surface.
Via (1959) described a new species, Pilumnoplax urpiniana from the Eocene of Spain. Feldmann and Maxwell (1990) referred this species to Carcinoplax and Schweitzer (2000) assigned it to the Pilumnidae. Via (1959, 1969) indicated that Pilumnoplax urpiniana has three anterolateral teeth, while in the species a broken fourth anterolateral tooth (Via, 1969, pl. 36, figs. 2, 2b) is observed. Pilumnoplax urpiniana possesses carapace and male abdomen characters most like those of members of Eucrate; the front has a median notch; the supraorbital angle is well marked; the upper orbital margin bears two shallow notches; the anterolateral margin has four anterolateral teeth; the male abdominal somites 5 and 6 are much narrower than somite 3; and the telson is much longer than wide. However, the species differs from species of Eucrate by having a flattened dorsal surface, well developed triangular anterolateral teeth, more or less defined cervical and branchiocardiac grooves, and well marked epibranchial regions. Therefore, Viaplax gen. nov. is here erected with a type species, Pilumnoplax urpiniana Via, 1959. The generic name is derived from the late Dr. L. Via, a Spanish paleontologist, and the suffix-plax (flat), which is used in names of related genera. The gender is feminine. The carapace of the new genus may also be similar to that of Benthopanope Davie, 1989, of the pilumnid Heteropanopinae Alcock, 1898, nom. transl. herein pro Heteropanopeinae Alcock, 1898, nom. transl. Serène (1984)). It is readily distinguished from Benthopanope by the possession of a wider orbital margin and well developed anterolateral teeth, and the absence of granular dorsal crests on the carapace and prominent median lobes on the frontal margin.
Vega et al. (2001) erected a new monotypic genus, Stoaplax, containing S. nandachare Vega et al., 2001, from the middle Eocene of México. They referred the genus to the Carcinoplacinae and indicated that it is most similar to Orbitoplax. Herein, the genus is removed to the Euryplacinae by having a medially notched frontal margin and a wide upper orbital margin with a fissure.
The Eocene genus Corallicarcinus possesses carapace characters like those of the extant Euryplax; however, in Corallicarcinus the carapace has distinct ridges extending onto the dorsal surface from the second and third anterolateral teeth.
Fossil records.
Seven genera including five extinct ones are known from the fossil record (Table 5). Four extinct genera are known from the Eocene and one is from the Pliocene. The geologic range of two extant genera, Eucrate and Euryplax, extend back to the Oligocene.
Table 5
Distributions and geologic ranges of recognized fossil species of the subfamily Euryplacinae. Asterisk indicates extant species.
Subfamily Goneplacinae MacLeay, 1838 emend.
(= Subfamily Carcinoplacinae H. Milne Edwards, 1852)
Diagnosis.
Carapace with poorly defined dorsal regions; front straight without median notch, sometimes with low median projection; notch between frontal margin and supraorbital angle indistinct; orbit without upper orbital fissures; anterolateral margin bearing one to three spines; eye stalk short or long; merus of maxilliped 3 subquadrate, much longer than ischium; male abdomen filling entire space between coxae of pereiopods 5, with all free somites; thoracic sternum wide with sutures all interrupted; sternite 7 with posterolateral prolongation; sternite 8 visible in posterior view; sterno-abdominal cavity reaching anterior of sternite 4; chelipeds usually with lateral spine on carpus and without dark-colored fingers; dactyli of pereiopods 2–5 without corneous tips; dactyli of pereiopod 5 styliform or spatulate, with or without setae; gonopod 1 stout, sinuous, usually with truncated apex; gonopod 2 usually long with long flagellum.
Genera included.
Bathyplax A. Milne Edwards, 1880; Carcinoplax H. Milne Edwards, 1852; Goneplax; Neom-matocarcinus Takeda and Miyake, 1969; Ommatocarcinus White, 1852; Psopheticus Wood-Mason, 1892; Singhaplax Serène and Soh, 1976.
Discussion.
The Goneplacinae was previously distinguished from the Carcinoplacinae by the following characters: carapace subquadrate in outline, greatest carapace width is at the outerorbital angle, front is usually narrow, and orbit is extremely elongate (Balss, 1957; Sakai, 1976; Hsueh and Huang, 2002). However, the Carcinoplacinae is herein recognized as a synonym of the Goneplacinae based upon the present analysis.
Via (1959) described a new species, Ommatocarcinus zariquieri, from the Eocene of Italy. In his 1969 work the present species was well figured. This species is not a member of Ommatocarcinus because the dorsal carapace possesses three well defined transverse ridges (Via, 1969, pl. 37, figs. 1, 1a, 2, 2a), the maximum carapace width is at the anterolateral angle.(Via, 1969, pl. 37, figs. 1, 1a, 2, 2a), there is a well defined median groove on thoracic sternites 2 and 3 (Via, 1969, pl. 37, fig. 1b), and male abdominal somites 3–5 are fused (Via, 1969, pl. 37, fig. 1b). In the possession of fused abdominal somites 3–5 Takeda and Miyake (1969) and Jenkins (1975) noted that the species may be transferred to Neommatocarcinus Takeda and Miyake, 1969, but O. zariquieri apparently differs from the sole included species of Neommatocarcinus, N. huttoni (Filhol, 1885), by carapace and thoracic sternum characters. The species is here assigned to Euphylax Stimpson, 1860, of the family Portunidae Rafinesque, based upon the characters discussed above. In Ommatocarcinus there is only one transverse ridge on the dorsal surface, the maximum carapace width is at the outerorbital angle, a median groove is absent on thoracic sternites 2 and 3, and all male abdominal somites are free.
Glaessner (1960) described Ommatocarcinus arenicola Glaessner, 1960, from the lower Miocene of New Zealand and noted that “The new species is closer in the shape of its carapace to the less specialized genus Goneplax Leach, but the front is more like that of Ommatocarcinus, to which the species is assigned as an early primitive form”. Takeda and Miyake (1969) proposed a new goneplacid genus, Glaessneria, for the species. We cannot concur. The carapace in this species bears two anterolateral teeth with an anterolaterally directed outerorbital tooth, has a relatively wide front without a median projection, and lacks a distinct transverse ridge dorsally; therefore, the species is here moved to Goneplax. Glaessneria thus becomes a junior subjective synonym of Goneplax.
Paleopsopheticus Hu and Tao, 1996, is a junior subjective synonym of Psopheticus. Hu and Tao (1996) distinguished the present monotypic genus from Psopheticus by having a small-sized carapace, a nearly straight anterolateral margin, a rounded posterior margin, and equal-sized anterolateral spines (modified from Hu and Tao, 1996, p. 102). We believe that these characters cannot define the genus but define Psopheticus shujenae (Hu and Tao, 1996) comb. nov. Examination of their figures (Hu and Tao, 1996, pl. 49, figs. 1, 2, 5, 6) suggests that the species is quite similar to most members of Psopheticus (i.e. P. stridulans Wood-Mason, 1892, P. vocans Guinot, 1985).
Glaessner (1960) described a new species, Galene proavita, from the Miocene of New Zealand. This species is here moved to Carcinoplax because the carapace has smooth, poorly defined anterior dorsal regions with a straight frontal margin, the thoracic sternum and male abdomen are wide, and the telson of the male abdomen is about as long as wide. In members of Galene the frontal margin is bilobed; the anterior mesogastric process is more or less defined; the cardiac region is longer than wide; the thoracic sternum is much longer than wide with a narrow sterno-abdominal cavity; the male abdominal somites 4–6 are much narrower than somite 3 with a long, elongate telson. Pilumnoplax petrificus Hu and Tao, 1996, from the Pleistocene of Taiwan, is identical with Carcinoplax prisca Imaizumi, 1961, because the carapace is rounded-hexagonal in outline and slightly wider than long, and a large outerorbital tooth is directed sharply forwards. Hu and Tao (1996) described a new species, Carcinoplax linae, from the upper Pliocene of Taiwan. They compared the species with Carcinoplax longimanus (De Haan, 1833) rather than with the quite similar extant species Carcinoplax purpurea Rathbun, 1914, and in fact no substantive difference between C. linae and C. purpurea can be found. Carcinoplax linae is here regarded as a junior synonym of C. purpurea.
Fossil records.
Four genera, Carcinoplax, Goneplax, Ommatocarcinus, and Psopheticus, are recognized as fossils (Table 6). Most species of these genera are known from the Neogene and two species, Carcinoplax temikoensis and Psopheticus shujense, are from the Palaeogene.
Table 6
Distributions and geologic ranges of recognized fossil species of the subfamily Goneplacinae. Asterisk indicates extant species.
Subfamily Carinocarcinoidinae subfam. nov.
Diagnosis.
Carapace with more or less defined dorsal regions; front straight without median notch; notch between frontal margin and supraorbital angle indistinct; upper orbital margin without fissures; anterolateral margin bearing three spines; merus of maxilliped 3 subquadrate, much longer than ischium; male abdomen filling entire space between coxae of pereiopods 5, with somites 3–5 fused; thoracic sternum wide; sternite 7 with posterolateral prolongation; sternite 8 visible in ventral view, overlying posterior of sternite 7; sterno-abdominal cavity reaching anterior of sternite 4; fingers of chelipeds long, elongate, not dark in color.
Discussion.
Karasawa and Fudouji (2000) originally placed Carinocarcinoides within the Carcinoplacinae. However, the phylogenetic analysis strongly suggests that the genus should not be assigned to the Carcinoplacinae (= Goneplacinae) based upon examination of type and newly obtained specimens. Carinocarcinoides is derived as the sister to the Trogloplacinae and Chasmocarcininae, and lacks diagnostic synapomorphies of both subfamilies. Carinocarcinoides is here treated as the type of a new subfamily. Based upon the present phylogenetic analysis, the Carinocarcinoidinae belongs in a monophyletic group with the Trogloplacinae and Chasmocarcininae within the Goneplacidae.
Fossil records.
Two species have been recorded from the lower Oligocene of Japan (Table 7).
Table 7
Distributions and geologic ranges of recognized fossil species of the subfamily Carinocarcinoidinae.
Subfamily Trogloplacinae Guinot, 1986
Diagnosis.
Carapace rounded, sometimes poorly calcified; dorsal regions poorly defined; front straight with shallow median indentation; notch between frontal margin and supraorbital angle indistinct; upper orbital margin narrow without fissures; anterolateral margin cristate, entire or toothed; eye stalk short; merus of maxilliped 3 subquadrate, about as long as ischium; male abdomen not filling entire space between coxae of pereiopods 5, with somites 3–5 fused; thoracic sternum wide with sutures all interrupted; sternite 7 with posterolateral prolongation; sternite 8 visible in ventral view, overlying posterior part of sternite 7, with supplementary plate; chelipeds without dark-colored fingers; dactyli of pereiopods 2–5 with or without corneous tips; dactyli of pereiopods 5 styliform with or without setae; gonopod 1 stout, sinuous, with simple apex; gonopod 2 long, about as long as gonopod 1, with flagellum about same length as peduncle (from Davie and Guinot, 1996).
Remarks.
The Trogloplacinae is derived as the sister group to the Chasmocarcininae based upon the present phylogenetic analysis. Davie and Guinot (1996) showed that the subfamily is most closely related to the Chasmocarcininae and is separated from it by the suture of the antennular region and differences in length and shape of the male gonopods.
Subfamily Chasmocarcininae Serène, 1964 emend.
Diagnosis.
Carapace with poorly defined dorsal regions; front straight with shallow median notch; notch between frontal margin and supraorbital angle indistinct; orbit usually small without upper orbital fissures; anterolateral margin entire or toothed, tapering anteriorly; eye stalk short; merus of maxilliped 3 suboval, about as long as ischium; male abdomen not filling entire space between coxae of pereiopods 5, with somites 3–5 fused; thoracic sternum wide with sutures all interrupted; sternite 7 with posterolateral prolongation; sternite 8 visible in ventral view, overlying posterior part of sternite 7, with supplementary plate; sterno-abdominal cavity reaching anterior of sternite 4; chelipeds without dark-colored fingers; fingers sometimes elongate, deflexed; dactyli of pereiopods 2–5 without corneous tips; dactyli of pereiopods 5 sickleshaped with setae; gonopod 1 stout, sinuous, with simple apex; gonopod 2 long, but shorter than gonopod 1, with flagellum much shorter than peduncle.
Genera included.
Camatopsis Alcock and Anderson, 1899, Chasmocarcinus; Chasmocarcinops Alcock, 1900, Collinsius Karasawa, 1993; Falconoplax Van Straelen, 1933, Gillcarcinus Collins and Morris, 1978; Hephthopelta Alcock, 1899; Mioplax Bittner, 1884; Orthakrolophos Schweitzer and Feldmann, 2001a; Parapilumnus Kossmann, 1877; Scalopidia Stimpson, 1858.
Discussion.
Serène (1964) originally included Megaesthesius Rathbun, 1909, within the Chasmocarcininae while Davie and Guinot (1996) excluded this genus from the subfamily. We concur with Davie and Guinot. Ng (2002) moved Parapilumnus, previously assigned to the Pilumnidae, to the Chasmocarcininae.
Schweitzer and Feldmann (2001a) recognized three extinct genera within the Chasmocarcininae. It is here expanded to include two genera Gillcarcinus and Mioplax. Collins and Morris (1978) erected the monotypic genus Gillcarcinus from the middle Eocene of Pakistan and referred the genus to the Xanthidae. The genus is moved to the Chasmocarcininae by having a narrow upper orbital margin without notches, a wide thoracic sternum, a narrow male abdominal somite 3, which does not fill the entire space between pereiopods 5, and fused male abdominal somites 3–5. Glaessner (1969) placed Mioplax from the Miocene of Austria within the Goneplacinae; however, the genus possesses a small orbit and long, slender deflexed fingers of chelipeds. Both characters strongly suggest that Mioplax should be assigned to the Chasmocarcininae. Gillcarcinus has three weakly developed anterolateral spines and Mioplax bears a well developed anterolateral spine. Most members of the Chasmocarcininae lack anterolateral spines, while the extant Hephthopelta aurita Rathbun, 1932, has two sharp anterolateral spines.
Fossil records.
Six genera are known from the fossil record (Table 8). Collinsius, Falconoplax, and Orthakrolophos are extinct genera. Fossil members of Chasmocarcinus are known from the Eocene of Antarctica and Miocene of the U.S.A.
Table 8
Distributions and geologic ranges of recognized fossil species of the subfamily Chasmocarcininae.
A review of remaining fossil genera
"Pilumnoplax Stimpson, 1858"
Guinot (1969a, b, c; Tucker and Feldmann, 1990) have already discussed the nomenclatural status of the generic name Pilumnoplax, and have shown that the genus was a heterogenous group. Bachmayer (1953b) described a new species, Pilumnoplax carnuntinus, from the Miocene of Austria based upon a single incomplete specimen. In this specimen the front, a part of the upper orbital margin, and a part of the gastric region have been preserved; therefore, the species is not classified within any known genus of the Goneplacidae (Müller, 1984; 1998). Pilumnoplax soledadensis Rathbun, 1926, described from the Eocene of the U.S.A., was moved to the panopeid genus Panopeus H. Milne Edwards, 1834 (Schweitzer, 2000).
Glyphithyreus Reuss, 1859 (= Plagiolophus Bell, 1858 non Pomel, 1847)
Glyphithyreus Reuss, 1859, has been placed within the goneplacid Carcinoplacinae (Balss, 1957, Glaessner, 1969 and many subsequent workers). Glyphithyreus lacks the poorly defined dorsal carapace regions, a straight front margin without median notch, the upper orbital margin with an indistinct supraorbital angle and without fissures, and a wide male abdomen with all free somites, all of which are diagnostic characters of the Goneplacinae (= Carcinoplacinae). Glyphithyreus is here placed in the panopeid Eucratopsinae because the carapace has well defined dorsal regions, the front consists of two rounded lobes, and the narrow male abdomen has fused somites 3–5. Previously known species of Glyphithyreus include: G. ellipticus Bittner, 1875, from the Eocene of Italy; G. markgrafi (Lörenthey, 1907 [1909]), from the Eocene of Egypt; G. sturgeoni Feldmann et al., 1998, from the Eocene of the U.S.A.; G. weaveri (Rathbun, 1926) from the Eocene of the U.S.A.; G. wetherelli (Bell, 1858) (type species) from the Eocene of Europe, Senegal, and Pakistan; and ? G. wichmanni Feldmann et al., 1995, from the Danian of Argentina. Among these, Glyphithyreus weaveri was moved to the euryplacine Orbitoplax (Schweitzer, 2000).
Galenopsis A. Milne Edwards, 1865
A. Milne Edwards (1865) erected the genus Galenopsis containing five species within his “Galénides”. Subsequently, Glaessner (1929) placed the genus within the Xanthidae, Balss (1957) and Glaessner (1969) removed it to the goneplacid Carcinoplacinae, and Schweitzer (2000) reassigned it to the Pilumnidae. We agree with Schweitzer's opinion. In Galenopsis a narrow, deflexed frontal margin is medially interrupted with prominent median lobes, and the narrow upper orbital margin possesses a distinct supraorbital angle. These characters do not match the diagnostic characters of the Goneplacinae (= Carcinoplacinae) but match those of the Pilumnidae as defined by Schweitzer (2000).
Galenopsis contains numerous species (Via, 1969) from the Eocene-Pliocene of Europe, Africa, India, and Fiji (Glaessner, 1969). Among these Müller and Collins (1991a) proposed a new monotypic genus, Lobogalenopsis, for Galenopsis quadrilobatus Lörenthey, 1897, from the upper Eocene of Hungary. Lobogalenopsis was also excluded from the Goneplacidae and has been transferred to the Pilumnidae (Schweitzer, 2000).
Palaeograpsus Bittner, 1875
Palaeograpsus has long been placed within the Grapsidae MacLeay, 1838 (Glaessner, 1969). Previously known species of the genus are Palaeograpsus attenuatus Bittner, 1875, P. bartonensis Quayle and Collins, 1981, P. depressus Quayle and Collins, 1981, P. guerini Via, 1959, P. inflatus Bittner, 1875 (type species), P. loczyanus Lörenthey, 1898a and P. parvus (Müller and Collins, 1991b) from the Eocene of Europe; and P. bittneri Morris and Collins, 1991 from the Pliocene of Brunei. Among these, Schweitzer and Feldmann (2001a) moved three species, P. bartonensis, P. bittneri and P. depressus, to Orthakrolophos within the Goneplacidae. Palaeograpsus guerini is similar to members of Orthakrolophos, but is characterized by having transverse ridges on the dorsal carapace, which are absent in Orthakrolophos; therefore, Schweitzer and Feldmann (2001a) did not include the species in Orthakrolophos.
Via (1969) suggested that P. loczyanus closely resembles members of Carcinoplax within the Goneplacinae. Karasawa and Kato (2001) also suggested that P. inflatus and P. loczyanus possess carapace and cheliped characters most like those of Carcinoplax and moved Palaeograpsus to the Goneplacidae. Reexamination of P. inflatus described by De Angeli (1995) strongly suggests that the genus does not belong within the Goneplacinae but within the panopeid Eucratopsinae or the Pseudorhombilidae because the front has a median notch (De Angeli, 1995, figs. 3.2, 3.4, pl. 2, figs. 2, 4), there are two fissures on the upper orbital margin (De Angeli, 1995, figs. 3.2, 3.4, pl. 2, figs. 2, 4), male abdominal somites 3 and 4 are incompletely fused (De Angeli, 1995, fig. 3.4, pl. 2, fig. 4) and male abdominal somite 1 fills the entire space between the coxae of pereiopods 5 (De Angeli, 1995, pl. 2, figs. 2–4). The panopeid Eucratopsinae is quite similar to the Pseudorhombilidae, and the differentiation between them is mainly based upon the male gonopod morphology (Hendrickx, 1998). However, male abdominal somite 1 in members of the Eucratopsinae does not fill the entire space between coxae of pereiopods 5; it is therefore considered best to place Palaeograpsus inflatus within the Pseudorhombilidae.
The monotypic genus Carinocarcinus Lörenthey, 1898b, described from the middle Eocene of Germany, possesses carapace and cheliped characters like those of Palaeograpsus sensu stricto; however, in Carinocarcinus the carapace is much wider than long with four anterolateral teeth. Carinocarcinus may be also referred to the Pseudorhombilidae.
Telphusograpsus Lörenthey, 1902
Glaessner (1969) showed that Telphusograpsus Lörenthey, 1902, from the Eocene of Rumania, was synonymous with the grapsid genus Varuna H. Milne Edwards, 1830; however, Karasawa and Kato (2001) suggested that Telphusograpsus is an independent genus and probably belongs to the Goneplacidae. Telphusograpsus, represented only by a carapace specimen, has a distinct supraorbital angle and upper orbital fissures; therefore, it could be referred to the Mathildellinae, the Euryplacinae, the Panopeidae or the Pseudorhombilidae. Complete familial and subfamilial arrangements of the genus must await discovery of the thoracic sternum and the male abdomen.
Laevicarcinus Lörenthey in Lörenthey and Beurlen, 1929
Laevicarcinus was originally placed within the Carcinoplacidae (= Goneplacidae), and within the goneplacid Carcinoplacinae by Balss (1957) and Glaessner (1969). Crosnier and Guinot (1969) indicated that the genus has a close resemblance to Platychelonion. Müller and Collins (1991a) reexamined the type specimen of the type species, Laevicarcinus egerensis Lörenthey in Lörenthey and Beurlen, 1929, from the upper Eocene of Hungary and removed Laevicarcinus to the Panopeidae.
Martinezicancer Van Straelen, 1939
Van Straelen (1939) described a new genus and species, Martinezicancer schencki, from the Palaeogene of California and suggested that the genus might represent a new family. Glaessner (1969) placed the genus within the Carcinoplacinae. Martinezicancer schencki has well defined dorsal regions, an arcuate protogastric ridge, an epibranchial region with two ovoid swellings, a mesogastric region with low transverse ridge, and a broad cardiac region with lobate swellings along lateral margins; therefore, it is assigned to Archaeopus Rathbun, 1908, redefined by Schweitzer and Feldmann (2001b), of the Retroplumidae Gill, 1894, and Martinezicancer becomes a junior synonym of Archaeopus.
Carcinoplacoides Kesling, 1958
The monotypic genus, Carcinoplacoides, erected with C. flottei Kesling, 1958, from the Pleistocene of Guam, was placed within the Carcinoplacinae (Kesling, 1958; Glaessner, 1969). Schweitzer et al. (2002) indicated that the species is synonymous with Libystes nitidus A. Milne Edwards, 1867, of the Portunidae.
Styrioplax Glaessner, 1969
Glaessner (1969) gave Styrioplax as a replacement generic name for Microplax Glaessner, 1928. This monotypic genus contains S. exiguus (Glaessner, 1928) from the Miocene of Austria. Glaessner (1969) did not place it in any known subfamily within the Goneplacidae. This genus is characterized by a small-sized carapace, a straight frontal margin with a median notch, small orbits, and a distinctly narrowed male abdomen. These characters indicate that the genus may belong to the Trogloplacinae, Chasmocarcininae, or pilumnid Rhizopinae sensu lato. The familial and subfamilial placements of Styrioplax remain obscure because detailed characters of the male abdomen of S. exiguus are poorly known.
Caprocancer Müller and Collins, 1991a and Eoplax Müller and Collins, 1991a
Müller and Collins (1991a) erected the two new goneplacid genera, Caprocancer and Eoplax, from the upper Eocene of Hungary. However, Müller and Collins (1991a) did not make any comparisons between Caprocancer and any known genera of decapods and indicated that there was a similarity between Eoplax and the grapsid genus Pachygrapsus Randall, 1840. The familial placement of both genera remains obscure because they are based upon poorly preserved carapace specimens.
Chumaoia Hu and Tao, 1996
Hu and Tao (1996) erected a new monotypic genus, Chumaoia, with C. johnferi Hu and Tao, 1996, from the Miocene of Taiwan. Karasawa (1997, p. 67, footnote) showed that the genus is a junior synonym of Typilobus Stoliczka, 1871, of the Leucosiidae Samouelle, 1819.
Pregeryona Hu and Tao, 1996
Hu and Tao (1996) described a new genus and species, Pregeryona taiwanica, from the Miocene of Taiwan. The familial placement of the genus is doubtful because their description was brief and their materials poorly preserved.
Maingrapsus Tessier et al., 1999 and Paracorallicarcinus Tessier et al., 1999
Tessier et al., (1999) erected a new grapsid genus, Maingrapsus, from the Eocene of Italy. Karasawa and Kato (2001) suggested that the genus resembles Paracorallicarcinus Tessier et al., 1999 and moved it to the Goneplacidae. Maingrapsus and Paracorallicarcinus possess carapace characters like those of the extant Georgeoplax Türkay, 1983 of the Pilumnidae (as Goneplacidae by Karasawa and Kato, 2001); therefore, both genera are removed to the Pilumnidae.
The current status of the sixteen genera discussed above is listed in Table 9.
Table 9
The current status of the remaining extinct genera previously assigned to the Goneplacidae.
Acknowledgments
We thank T. Komai (Natural History Museum and Institute, Chiba), L. Lemaitre and W. C. Blow (National Museum of Natural History, Smithsonian Institution, Washington, D.C.), P. Müller (Hungarian Geological Survey, Hungary), C. Beschin and A. De Angeli (Museo Civico “G. Zannato”, Italy), and T. Sato (Kanagawa Prefectural Museum of Natural History) for loans of their material. We also thank D. Guinot (Muséum national d'Histoire naturelle, Paris), and Z. Stevcic (Center for Marine Research, Croatia) for providing valuable comments about some taxa of the Goneplacidae; T. Kimura (Gunma Prefectural Museum of Natural History) for providing valuable information about the phylogenetic analysis; and A. Garassino (Museo Civico di Storia Naturale in Milano, Italy) and A. De Angeli (Museo Civico “G. Zannato”, Italy) for providing copies of classical literature. We are deeply indebted to C. L. McLay (University of Canterbury, New Zealand), P. K. L. Ng (National University of Singapore), and C. E. Schweitzer (Kent State University, U.S.A.) for reading our manuscript and providing useful comments. Special thanks are due to R. M. Feldmann (Kent State University, U.S.A.) and an anonymous referee for their review of the manuscript. Travel for examination of Hungarian fossils was provided by a special fund from the Mizunami Municipal Government to Karasawa.
