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New anatomical details are described for the acanthodian Lupopsyrus pygmaeusBernacsek & Dineley, 1977, based on newly prepared, nearly complete body fossils from the MOTH locality, Northwest Territories, Canada. New interpretations of previously known structures are provided, while the head, tail, and sensory lines of L. pygmaeus are described for the first time. The pectoral girdle of L. pygmaeus shows no evidence of pinnal and lorical plates as mentioned in the original species description. Instead, the dermal elements of the pectoral region appear to comprise a single pair of prepectoral spines which rest on transversely oriented procoracoids, and large, shallowly inserted, ornamented pectoral fin spines which contact both the procoracoids and scapulocoracoids. The scales of L. pygmaeus lack growth zones and mineralized basal tissue, and superficially resemble scales of thelodonts or monodontode placoid scales of early chondrichthyans, and not the typical scales of acanthodians. However, L. pygmaeus possesses perichondrally-ossified pork-chop shaped scapulocoracoids, a series of hyoidean gill plates, and scale growth that originates near the caudal peduncle; these features suggest a relationship to acanthodians. Prior to this study, both authors conducted separate cladistic analyses which resulted in differing tree positions for L. pygmaeus and its relationships within the Acanthodii. However, both analyses did agree that there is no evidence allying L. pygmaeus to the traditional “climatiid” acanthodians contrary to previous historical classifications.
OriocrassatellaEtheridge Jr., 1907 is a long range crassatellid bivalve genus well recognized in shallow waters of epeiric seas throughout the upper part of Paleozoic. The first occurrences of this genus are recorded in the sedimentary successions of the Gondwana, both in Australia and South America. However, the geographic and age distribution of Oriocrassatella in Late Mississippian deposits of Australia and Argentina may indicate an earliest Visean or even a pre-Visean origin for the genus. Following its origin in Early Carboniferous a complex paleobiogeographic history from Southern to Northern Hemisphere took place in the Permian. During its initial dispersal phase from Late Carboniferous to the Early Permian the genus thrived in cold water environments associated to the Late Paleozoic Gondwana glaciation. Shallow-water bottoms of the warm waters of the central Gondwana fringe and Laurussia were colonized by Oriocrassatella only during Early Permian times when the genus became cosmopolitan. A new species of this genus is described herein, Oriocrassatella piauiensis n. sp., recorded from the Piauí Formation, Pennsylvanian of the Parnaíba Basin. This new species may represent an early adaptation to warm waters. However, based on available data, species of this genus seem to have adapted definitely to warm water environments probably related the Late Pennsylvanian interglacial phases. In these phases, climatic barrier were interrupted allowing the faunal interchange and larval dispersion following a South to North migration route through the eastern margins of Gondwana and the eastern Paleotethys.
Biomechanical analysis of the jaw apparatus in eucynodont traversodontids from the Triassic of Madagascar.
Mandible biomechanics analysis cannot take place without the understanding of the development degree and the arrangement pattern of the adductor muscles. In the non mammalian cynodonts, the temporal and the superficial masseter muscles play a primordial role in the lower jaw motion during the food processing. They constitute the key elements of this analysis. Previous studies on non mammalian cynodonts including Dadadon isaloiFlynn, Parrish, Rakotosamimanana, Simpson & Wyss, 1999 and Menadon besairieiFlynn, Parrish, Rakotosamimanana, Simpson & Wyss, 1999 demonstrated the realization, by these animals, of a complex dynamic occlusion of the lower and superior postcanine teeth. The consideration of the bite point as second occlusal fulcrum equal in status to the cranio-mandibular joint is the basis of the bifulcral model. This methodology allows: 1) to quantify the resistance opposed by food at the level of the occlusal site; and 2) to highlight a positive net vertical load, of compressive nature, acting to the level of the cranio-mandibular joint during the interactivity of the elevator muscles, i.e. during mastication.
KEYWORDS: ammonites, Jurassique inférieur, stratigraphie, morphologie, Adaptation, diversité, disparité, genre nouveau, espèce nouvelle, Early Jurassic, stratigraphy, morphology, diversity, disparity, new genus, new species
Oxyarietites boletzkyi n. gen., n. sp., a new genus and species of ammonite for the Lower Sinemurian of Burgundy (France): a rare forerunner of the oxycone morphologies for the Jurassic.
One of the very first quasi-oxycone ammonites following the Triassic/Jurassic boundary crisis is described. It was collected from the fossiliferous Lower Sinemurian (Semicostatum or Turneri Chronozone) strata of Burgundy (Mavilly-Mandelot, Côte-d'Or, France). The new taxon, Oxyarietites boletzkyi n. gen., n. sp., possesses an involute, compressed and keeled shell of suboxycone morphology, a shell type previously unknown for the Lower Sinemurian. The discovery makes younger by about 2 Ma the emergence of keeled (sub)oxycone shells following the Triassic/Jurassic boundary crisis. Its obviously keeled ventral area allows a probable assignation to the Arietitoidea Hyatt, 1875 sensu Guex (1995) superfamily, but family level assignation and its evolutionary origin remain obscure. Although, it is generally accepted that involute, compressed and keeled suboxycone and oxycone ammonite shells possess the best hydrodynamical abilities and mobility, the acquisition of this probable adaptive advantage in O. boletzkyi n. gen., ç. sp. does not go together with abundancy in the fossil record.
The Oxfordian fauna from the Terrain à Chailles Formation, eastern France (Haute-Saône, Franche-Comté) is remarkable for its exceptionally preserved crustaceans found in siliceous concretions locally named “chailles”. The crustacean fauna includes 9 different species assigned to the Glypheidae, the Erymidae, the Eryonidae and the Axiidae. Glypheid and erymid lobsters are the most diversified groups with four and three different species respectively. Re-examination of numerous new specimens allows to a more modern and more complete characterization of Glyphea regleyana (Desmarest, 1822), Glyphea muensterivon Meyer, 1840 and Eryma ventrosa (von Meyer, 1835). New detailed anatomic descriptions of these species highlight the presence of marked sexual dimorphism in G. regleyana and probably in E. ventrosa. They reveal processes of autotomy and phenomena of ecdysis in G. regleyana, E. ventrosa and G. muensteri. Quantitative analyses based on 424 nodules show three dominant species: 1) Glyphea regleyana (50.5% of nodules); 2) Eryma ventrosa (24.8%); and 3) Glyphea muensteri (16.5%). Convergent lines of evidence from depositional environment, comparisons with others Jurassic crustaceans and modern analogues indicate that the crustacean fauna from the Terrain à Chailles Formation probably inhabited a moderately deep water setting most probably about 100–150 m (lower circalittoral zone) where light intensity was even sensitive. These crustaceans constitute a very original assemblage intermediary between the communities from the shallow carbonate platforms (e.g., Solnhofen) and those from the bathyal zone (e.g., La Voulte). This new set of data sheds new light on the colonization of the distal platforms by crustacean communities in the Mesozoic.
KEYWORDS: Polyphaga, Elateriformia, Albian, Mesozoic, Burma, taxonomy, new genus, new species, Albien, Mésozoïque, Birmanie, taxonomie, genre nouveau, espèce nouvelle
The first Mesozoic fossil of the beetle family Ptilodactylidae Laporte, 1836 (Byrrhoidea) is formally described and figured from a male preserved in latest Albian amber from Myanmar. Aphebodactyla rhetine n. gen., n. sp., is distinguished from its modern relatives and is only the second fossil species yet formally described in the family. The fossil intermingles putatively derived features of various ptilodactylid subfamilies, suggesting that the current circumscription of these lineages is in dire need of revision.
Thirty echinoid species (18 regular and 12 irregular) and an undetermined species belonging to 14 genera are studied from the Turonian-Santonian sequence (14 species from Turonian, two species from Turonian-Santonian and 14 species from Coniacian-Santonian) of Abu Roash, Wadi Dakhl and Wadi Abu Qaada, Egypt. Two new species are established: Thylechinus (Thylechinus) sinaiensis n. sp. from the Turonian of Wadi Abu Qaada and Toxaster dakhlensis n. sp. from the Turonian of Wadi Dakhl. Orthopsis ovata (Coquand, 1862), which is known in other parts of the Tethyan region, is reported for the first time from Egypt. The rank of one subspecies is raised to species level: Coenholectypus roachensis (Fourtau, 1914) n. stat. The generic name of three species is changed: Echinobrissus humeiFourtau, 1906 is changed to Petalobrissus humei (Fourtau, 1906) n. comb.; Periaster duncani (Fourtau, 1906) and Periaster roachensis Gauthier, 1900 are transfered to the genus Mecaster Pomel, 1883. The ontogenetic changes of Mecaster turonensis (Fourtau, 1921) are described. The biostratigraphy and paleobiogeography of the fauna are discussed.
We report on the first occurrence of Maastrichtian bird material from the Peirópolis locality (Uberaba district), Minas Gerais State (Brazil). The specimens consist of an indeterminate pedal ungual phalanx (CPP 481), a pedal phalanx 1 of left digit II (CPP 470) and an incomplete metatarsal III (CPP 482). The material can be assigned to Aves gen. et sp. indet. (CPP 470 and CPP 481) and to cf. Enantiornithes gen. et sp. indet. (CPP 482). Despite the isolated and incompleteness nature of these specimens, they add to the otherwise poor record of Cretaceous birds from Brazil.
The gadid fish Palimphemus ancepsKner, 1862 is redescribed in detail based on 43 specimens from the Miocene deposits of St. Margarethen, in the Eisenstadt-Sopron Basin, Burgenland, Austria. The morphoanatomical analysis of the material referred to Palimphemus anceps revealed that it can be distinguished from other members of the family Gadidae Rafinesque, 1810 by a unique combination of characters, including: elongated and laterally compressed body, head length about 1/3 of SL, large massive neurocranium with outer margins of the frontals thickened and ornamented by longitudinal pits and ridges along the ventral surface, hyomandibula with large ventrally directed preopercular process, opercle with a thick horizontal rib arising from the articular condyle, anal-fin insertion well behind the first dorsal-fin origin; preanal distance exceeding the base length of the first anal fin, length of the first anal-fin base reduced, 45–46 (18 27/28) vertebrae, third dorsal fin with 17–21 rays, first anal fin with 18–21 rays, second anal fin with 18–19 rays, caudal fin with 41–43 rays, and pectoral fin with 15–18 rays. Palimphemus anceps appears to be a basal gadine closely related to the genus Micromesistius Gill, 1867. Like other basal gadine genera — Gadiculus Guichenot, 1850, Micromesistius and Trisopterus Rafinesque, 1814 — Palimphemus anceps possibly was a thermophilous gadid that inhabited the shallow waters of the central Paratethys during the Middle Miocene.
The hypsodont Myomiminae Daams, 1981 (Gliridae) from the lower part of the Tudela Formation (Ebro Basin) are described. Five localities (CH1, CA2, CA3, CA4 and CC1) of this formation contain remains of the hypsodont genus Armantomys de Bruijn, 1966 and CC1 has also yielded Praearmantomys de Bruijn, 1966. Despite the poor material, we can identify the taxa A. cf. bijmai, A. daamsi (de Visser in Álvarez-Sierra, Daams, Lacomba, López Martínez, Van Der Meulen, Sesé & De Visser, 1991), A. cf.parsani, A. cf. jasperi and cf. P. crusafonti, which are characteristic of the Agenian and Ramblian continental stages. These data allow identification of the Agenian-Ramblian boundary in the Tudela Formation, and provide a calibration of this boundary on the basis of available magnetostratigraphic information.
Systematic excavations in the Early Pleistocene site of Pirro Nord (Apulia, southern Italy) yielded some remains of a relatively rare mustelid belonging to the subfamily of Galictinae Reig, 1956. The taxonomy of extinct genera within this clade is controversial, especially between PannonictisKormos, 1931 and EnhydrictisForsyth-Major, 1901. Nevertheless, the Pirro Nord findings are very similar to the holotype of Pannonictis nestii (Martelli, 1906) from Upper Valdarno, and closely related to the specimens from Pietrafitta and Atapuerca.
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