Description of a new trapdoor spider species, Nemesia amicitia spec. nov., from southern Spain, and new information on Nemesia uncinata (Araneae: Mygalomorphae: Nemesiidae)

Abstract. A new species of trapdoor spider found in southern Andalusia, Spain, Nemesia amicitia spec. nov., is described. This species builds a branched burrow with a characteristic wafer-type trapdoor over a curb around the entrance. In the same geographic area, two populations of N. uncinata Bacelar, 1933 have been found. New data about the morphological variability of this species and the structure of its burrow are provided. Zusammenfassung. Eine neue Falltürspinnenart, Nemesia amicitia spec. nov., wird aus Andalusien (Südspanien) beschrieben. Diese Art baut einen verzweigten Bau mit einer charakteristischen waffelartigen Falltür über eine Umrandung um den Eingang herum. Im selben Gebiet wurden zwei Populationen von N. uncinata Bacelar, 1933 gefunden. Neue Daten über die morphologische Variabilität dieser Art und die Struktur ihres Baus werden vorgelegt. Resumen. Se presenta la descripción de una nueva especie de araña trampera, Nemesia amicitia spec. nov., encontrada en el sur de Andalucía, España. Esta especie construye una madriguera bifurcada con una trampilla característica de tipo oblea sobre una pared circular alrededor de la entrada. En la misma área geográfica se han encontrado dos poblaciones de N. uncinata Bacelar, 1933; se proporcionan datos complementarios sobre su variabilidad morfológica y la estructura de sus madrigueras, comparándolas con las de la nueva especie.

. Both qualitative and quantitative characters were taken into account. In addition, the length and width of the embolus, the length of the tibia l spur and the width of the palpal tibia are provided. Studies of the epiandrous fusillae follow Zonstein (1987Zonstein ( , 2009. The ratios of the number of epiandrous fusillae/carapace length, length/width of palpal tibia in males and their means and standard deviations were also calculated. The ratio diameter of trapdoor (t) / diameter of entrance (e) of 100 burrows of the new species and the eight available ones of N. uncinata was calculated, as well as the mean and standard deviations of this parameter (Fig. 2a).
Spine formulae of palps and legs in the holotype are given as the number of spines on the left and the number of spines on the right for each one of the segments, both numbers sepa rated by a dot. Variations are given with the same formula, but between parentheses.
Abbreviations of body and legs parts: BL: Body, length; Ca: caput, length; Ch: Caput, height; CL: carapace, length; CW: carapace, width; Th: Thorax, height; Cly: Clypeus, length; AER: anterior eye row, length; PER: posterior eye row, length; ALE: anterior lateral eye, length; PLE: poste rior lateral eye, length; AME: anterior median eye, length; PME: posterior median eye, length; El: Eye length; POP: pattern of the deep black pigmentation on the ocular pro cess; Ml: maxillae, length; Mw: maxillae, width; Ll: labium, length; Lw: labium, width; Sl: sternum, length; Sw: sternum, width; Bu: bulb, length (Fig. 2b); Em: embolus, length (  cluded in a group of species which combines the Btype of males (characterized by enlarged, compact and ornamented bulbs) with the Etype of females (bagshaped spermathecae with one or two sections). Males of N. amicitia spec. nov. have compact and spherical bulbs, with a curved and nar row embolus (Fig. 3). The palpal tibia ratio is 1.89±0.08 and, when alive, males show a compact black pattern on the pro soma. Females present spermathecae that resemble two fun nels, with their tubes slightly curved (Fig. 3). Nemesia amicitia spec. nov. and N. uncinata seem to be closely related consid ering their morphology, trapdoor type and life cycle, which agrees with the DNA analysis that Miquel Arnedo (Univer sitat de Barcelona) made in 2019 (unpubl., pers. comm). Fe males of N. uncinata from the Cádiz population and N. amici tia spec. nov. are similar and can only be separated from the new species by their bagshaped or hillshaped spermathecae (Fig. 3). However, in males of N. uncinata, the colour pattern (both alive and preserved), the range of the palpal tibia ratio is 2.25±0.04 and, above all, the morphology of the bulbs al lows an easy differentiation (Fig. 3). Their burrows present a different structure, highlighting the presence of true branch ing in the gallery of N. amicitia (Fig. 4), suggesting that their behaviour is a phenotypic character that helps to distinguish species or species groups in Nemesia. The structure of sexual organs reveals some similarities with other Iberian species, mainly N. dorthesi (Thorell, 1875) and N. athiasi (Franganillo, 1920). Nemesia dorthesi is recorded in Andalusia by Zonstein (2019). According to the photographs provided in Zonstein (2019), the embolus of males is slightly narrowed, with a curve in the middle and present an arrowshaped tip in the end; females have sacshaped spermathecae. These characters contrast with the morphology of sexual organs in N. amicitia spec. nov. The copulatory organs of N. athiasi could resemble those of N. amicitia spec. nov. but, in males, the bulbs are less globous and more elongated, the morphology of the tip is simpler and the ventral denticles are smaller (Decae et al. 2007). In females, each spermatheca is narrow and straight on the distal half with a ring of glandular tissue (Decae et al. 2007). Finally, N. athiasi builds a branched burrow with two similar trapdoors. By contrast, the burrow of N. amicitia spec. nov. has only one trapdoor.

Description. Male (holotype)
Habitus. Black prosoma, crest zone grey and one grey stain on each cheek. Browngrey opisthosoma, poorly defined dark cardiac mark and multiple dots with three chevrons on the distal area in living specimens (Fig. 5a). Overall dark coloured in alcohol. Carapace with a medalshaped pattern of black pubescence, long hairs and some bristles on the posterior margin. White pubescence on light zones of prosoma (Fig.  5b). Prosoma. Clypeus light, flanked by two flecks, with a row of four bristles and a crest of white pubescence. POP black and broken between AME. Caput slightly elevated. Crest zone with a row of five setae, whitish or light grey in living specimens. Fovea shallow. Chelicerae black, with dorsal and retrolateral stripes without white pubescence. Cheliceral ras tellum of four-five strong spikes. Fang ridge with smooth keel. Cheliceral furrow teeth with six conical teeth on the promargin and a few small mesobasal denticles arranged in one row. Sternum lighter than other prosomal structures, the first pair of sigillas marginal and poorly visible; the second pair submarginal, the third pair ovoid and somewhat far from the margin. Maxillae along probasal heel with a few long bris tles instead of cuspules. Labium dark and similar in colour to coxae; its anterior margin lighter and covered by a row of black setae (Fig. 5c). Pedipalp and legs I-IV. Cymbium dorsal patch of 19 thin spines in the holotype; 8-13 spines in two other specimens. Bulb proximal spherical, robust, gradually narrowing embolus, distally curved and sharp pointed, with a deep furrow and thin denticle in the ventral zone ( Fig. 5e). Tibia of palp 1.89±0.08 times longer than wide, with an apical dorsal patch of 8-13 spines (Figs. 5d-e). Clasper hook curved inwards, placed on inner side of tibia in ventral view. Clasper field convex in its proximal zone, with a few tiny hairs and small coneshaped cuspules from the middle to the proximal zone metatarsus I straight ( Fig. 5f ). Femora slightly darker than the other arti cles. Scopulae on tarsi, metatarsi, tibiae and patellae on legs I and II sparser on proximal articles. On legs III and IV, scopu lae only present on tarsi. Trichobothria patterns like in other Nemesiidae (see Decae et al. 2007

Female (allotype)
General appearance. Colouration as in male holotype, but prosoma whiter and more grey than brown when alive (Fig.  6a), more reddishyellow when preserved in alcohol. Dark cardiac mark, five-six chevrons of dots on the posterior area of the opisthosoma and cream colour on its ventral side. Prosoma. Clypeus lightly pigmented, three marginal bristles and one spot on each side. POP black, with a clear line be tween AME; some specimens with ALE, PLE and PME in a black fleck and each AME isolated. Caput elevated. Crest zone lightly pigmented, crestrow with seven setae. Fovea shallow and with two rows of three bristles on its anterior margin (Fig. 6b). Chelicerae black, with white stripes on their dorsal and retrolateral sides. Cheliceral rastellum consisting of five-six spikes. Fang ridge smooth. Cheliceral furrow with six promarginal conical teeth and a few small mesobasal den ticles. Maxillae dark, similar in colour to coxae and a row of four coneshaped cuspules on each one. Labium and sternum as in the holotype (Fig. 6c were usually found on slopes and between roots of cork oaks, Quercus suber L., wild olive, Olea europaea var. sylvestris (Mill.) Lehr, palmetto, Chamaerops humilis L., or other bushes. Ne mesia amicitia spec. nov. builds a horizontal rigid wafertype trapdoor which leans on the internal edge of a curb of par ticles and silk surrounding the entrance. The mean ratio t/e is 2.16±0.37, which means that there is a space between the curb and the real entrance. There is a small sheet of silk at the entrance that the spider closes when disturbed. The burrow has a main gallery that runs vertically downwards. A deadend branch begins 3 cm from the entrance and is angled upwards, approaching the surface. The first part (about 3 cm) at the be ginning of the main gallery and the whole auxiliary gallery are  . 7: Nemesia amicitia spec. nov. a, b. closed and open trapdoor, respectively; c. closed entrance; d. hunting specimen waiting for prey; e. internal structure of a burrow; f. habitat where this species was found for the first time and mature males were collected covered by silk and are narrower than the rest of the burrow. The carcasses of prey items usually accumulate at the end of the principal gallery, at a depth of about 18-20 cm (Fig. 7). Adult males were collected in the last half of September, when their reproductive cycle starts. Females build their egg sacs in summer and deposit them close to the deeper end of the principal gallery. At the end of summer, females moult and some days later the spiderlings disperse from their mother's burrow. This happens about a month before adult males begin to emerge from their burrows (personal observation, CP). Bacelar, 1933 New information on N. uncinata (intraspecific variation and previous descriptions) are given based on specimens collected from two populations of N. uncinata found in Cádiz province.

Male
General habitus. Bacelar (1933) and Decae et al. (2007) provided details based on conserved specimens. According to our observations on live specimens, these spiders are black, grey and brown on the prosoma, and pale yellow and brown on the opisthosoma when they are alive. The general colour turns to brownyellow and the dark areas of the prosoma be come more apparent when preserved in alcohol (Fig. 8ab). Opisthosoma as described by Bacelar (1933). Prosoma. The following variations and/or details were not commented on before in other studies. The clypeus is light with two black stains, with a row of five bristles and a crest of white thin hair. POP is black with light stripe between AME in specimens from the present study, while POP is compact and black in the description of Decae et al. (2007). The crest zone is light coloured and has seven to eleven setae. The cheli cerae have a rastellum formed by four-five strong spikes and each cheliceral furrow has six flattened teeth on the promar gin and a row of small mesobasal denticles. Coxae, labium and maxillae are dark coloured and the sternum is light coloured with small, from oval to elongate and submarginal sigilla (sometimes poorly visible) (Fig. 8c). Palp and legs I-IV. The cymbium is short and its dorsal patch bears 14-19 thin spines. Palpal tibia is 2.25±0,04 times longer than wide (Fig. 8d), with six-nine dorsal spines, which differs from Portuguese specimens described by Bacelar (1933), that bear a dorsal patch on the tibia of eleven spines and their tibia are almost two times longer than wide. The clasper hook is as in N. amicitia spec. nov. and the clasper field is convex, with a few tiny hairs and small cuspules (Fig. 8e). Metatarsus I is slightly curved (Fig. 8f ). The scopula extends from tarsus to patella on legs I-II, it is thinner on proximal articles. Legs III-IV only with tarsal scopula. One male from the sample collected in Cádiz has maculae on the prolateral side of fem ora I, II, III, IV and on the retrolateral side of I, II and III; in the other two specimens, maculae are visible on the prolateral side of femora I, II and retrolateral side of III and IV. By con trast, maculae are absent in the Portuguese males. The MTF4 ratio in the population of Cádiz is metatarsus > femur > tibia; meanwhile, in spiders described by Decae et al. (2007), this ratio is tibia > metatarsus, metatarsus = femur. Prolateral and retrolateral spination. The specimens from Cádiz vary in the number of spines on whole leg I, some dif ferences on retrolateral spines of legs II, and the retrolateral metatarsus of III and IV compared to specimens described by Bacelar (1933) Opisthosoma. The epiandric area is triangular (Fig. 8g) and has 37 epiandrous fusillae. Ratio carapace length/number of epiandrous fusillae 6.73±0.32. Measurements. Details of the variability of some metrics in the population of N. uncinata from Cádiz are given below. Com pared with specimens previously studied by Bacelar (1933) and Decae et al. (2007), Spanish specimens seem to be slightly smaller (body length up to 12.47 mm versus 15 mm in the Por tuguese specimens). Nevertheless, the length of the carapace of all populations is in the same size range. Bl: 9.35-12.47; dorsal area of prosoma: Ca: 3.13-3.32; Ch:

Ecology
The habitat from "La Cañada de los Ratones" (Alcalá de los Gazules) is a "dehesa" system with cork oak, Q. suber L, holm oak, Q. ilex L, wild olivetree, O. europaea var. sylvestris (Mill.) Lehr, and a grass layer covering the soil. The population from Torrecera ( Jerez de la Frontera) occurs in an open "dehesa" with predominance of mastic, Pistacia lentiscus L, wild olivetree, palmetto, C. humilis L, and poor or absent grass layer covering the soil. In both habitats, N. uncinata builds burrows with some with some details differing compared to those of to those of N. amicitia spec. nov.: its mean ratio t/e is 1.70±0.26 (i.e. there is less distance between the curb and the real entrance of bur row), its auxiliary branch is shorter (1.5-2.0 cm of length) than the branch that N. amicitia spec. nov. builds, and the depth of the principal gallery is lower, about 9.0-11.5 cm (Fig. 10). Nemesia uncinata uses the auxiliary branch to accumulate prey remains, meanwhile N. amicitia spec. nov. accumulates these re mains at the end of the principal branch. Males were collected during autumn and spiderlings were seen with their mother in September, suggesting that the reproductive biology and phe nology of this species is similar to that of N. amicitia spec. nov.

Discussion
The species studied in this work belong to the BE group es tablished by Decae (2012). This group includes N. caementaria (Latreille, 1799), N. carminans (Latreille, 1818), N. dorthesi, N. santeugenia (Decae, 2005), N. santeulalia (Decae, 2005), N. uncinata Bacelar, 1933 andN. valenciae (Kraus, 1955). Mora (2015) demonstrated with DNA analysis that species of this group belong to different, not related clades: N. cae mentaria and N. carminans were included in the same clade and the remaining species (N. santeulalia, N. uncinata, N. va lenciae and N. dorthesi) in another lineage, with a significant separation between both clades. Nemesia caementaria and N. carminans are similar considering their morphology, sexual organs and type of trapdoor (Latreille 1799, 1818, Moggridge 1873, 1874, agreeing with the results of DNA analysis car ried out by Mora (2015). The remaining species of the BE group share the type of sexual organs and some similarities between known females; the DNA analysis places N. unci nata at the base of this second lineage. The information about burrows presented in Decae (2005) and in the present work supports the idea that N. uncinata belongs to a different clade than N. santeulalia and N. dorthesi/valenciae. The trapdoor of the first species consists of a rigid wafertype trapdoor with a curb before the real entrance; in contrast, N. santeulalia builds a thin and flexible trapdoor (Decae 2005: fig. 73). Unfortu nately, the burrows of N. dorthesi and N. valenciae are still unknown. In terms of morphology, their sexual organs are the most outstanding differences. Females of N. santeugenia (the conspecific male is unknown) and N. santeulalia present potatoshaped receptacles but with different proportions, N. uncinata has bagshape spermathecae and the spermathe cae of N. amicitia spec. nov. resemble curved funnels. Males of N. santeulalia have the proximal zone of the embolus with a similar width than the bulb and progressively narrowed to the end with an arrowshaped tip (Zonstein 2017: figs. 21, 22), while N. uncinata has a widened and shorter embolus with ventral denticles on the distal zone. Also, the embolus of N. amicitia spec. nov. is thinner than in the other two species, with distal ventral denticles. The photographs of the bulbs of N. valenciae (Zonstein 2017: figs. 4041) andN. dorthesi (2019, figs. 109, 111113) are similar to the bulb of N. san teulalia, but in N. valenciae the bulb is more spherical and somewhat prominent and the middle of the embolus is angu lated in N. santeulalia and N. dorthesi. The bulb of N. dorthesi is more flattened and the angle on the middle of the embolus is more acute than N. santeulalia.
Some authors, like Latreille (1818), Moggridge (1873Moggridge ( , 1874, Decae (2005), Decae et al. (2007) and Decae & Hu ber (2017), recorded and described many species from Europe and the Mediterranean region and gave some descriptive in formation of their behaviour. Works like these reveal the high diversity of burrows these spiders build and the wide range of habitats where they can be found. The integration of these characteristics could be specific to species or species groups and of help in species determination (Mora 2015), and in ge neral the type of burrow might also be a valuable character in phylogenetic analyses. For example, it seems possible that species or group of species are associated with a certain type of burrow (Mora 2015).
Regarding the knowledge on the geographical distributi on of Nemesia species in Cádiz province (southern Spain), the models presented by Decae et al. (2007) show some species originally described from Portugal to be present in Cádiz: N. uncinata, N. athiasi and N. fagei (Frade & Bacelar 1931). However, only the first species has been detected until now in the studied area (personal observation, CP). The populations of N. amicitia spec. nov. and N. uncinata do not overlap in their distribution, but they cohabit with other unpublished species attributable to the Nemesia BE and CF group (sim ple pyriform bulbs and tubular shape spermathecae). In fact, N. amicitia spec. nov. usually shares its habitat with undeter mined species belonging to the group CF, except for the lo cation of "Pinar del Rey", San Roque, where another unpub lished species of the BE group with different morphology and type of trapdoor has been found. Mora (2015) proposed that the Baetic System Mountain range, that includes Cádiz province, represents the centre zone of diversification of Nemesia species and probably hou ses multiple unknown species, so the number of taxa officially recorded in Andalusia is still lower than one might expected. In general, the current knowledge of these spiders is poor due to their hidden lifestyle in a burrow, the ambiguity and im precision of old descriptions (some of them based only on one sex or a unique specimen), and the loss of type material. These shortcomings induce difficulties in the identification of species included in the genus, false records and, as a result, erroneous distribution limits, as well as further taxonomic problems on higher levels.