Drassodex Murphy 2007
Creators: name: Hervé, Christophe
name: Roberts, Michael J.
name: Murphy, John A.
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Gnaphosidae
Drassodex

description: Drassodex Murphy, 2007
Type species: Drassus hypocrita Simon, 1878, by original designation.
Drassodes Simon, 1893: 359 (in part, hispanus -group); Simon, 1914: 120 (in part, hypocrita -group). Drassodex Murphy, 2007: x, 11; Platnick, 2008.
Remark. The illustration of the male bulb of “ Drassodes gr. hypocrita ” by Barrientos (1986: fig. 2) clearly shows that the specimen doesn’t belong to the genus Drassodex but to the genus Clubiona Latreille.
Diagnosis. Members of the genus Drassodex can be easily distinguished from all other Palaearctic gnaphosids by the combination of the following characters (those in parentheses are characters observed in Drassodes sensu stricto): metatarsal preening combs on legs III and IV absent, replaced by preening brushes, dorsal male scutum absent, plain-coloured abdomen, dorsal spines on tibiae III and IV absent (present), trochanters slightly notched (deeply notched), retromarginal teeth as large as distal promarginal teeth (small or minute retromarginal teeth), and presence of some singular and well defined genitalic characters, as bifid RTA, highly coiled or twisted embolus, very deep epigynal atrium, bordered with slightly sclerotized lateral and hood-like anterior margins, and strongly corkscrew-shaped internal membranous coils.
Included species. D. hispanus (L. Koch, 1866), D. heeri (Pavesi, 1873), D. hypocrita (Simon, 1878), D. cervinus (Simon, 1914), D. fritillifer (Simon, 1914), D. validior (Simon, 1914), D. lesserti (Schenkel, 1936), D. simoni sp. nov. D. drescoi sp. nov., D. granja sp. nov.
Description. Total length: 8.09–17.57. Carapace (Murphy 2007: figs p. 232, 234) oval in dorsal view, widest between coxae II and III, with ocular area narrowed, light brown posteriorly, darker anteriorly, without darkened lateral edge; cephalic area not elevated; thoracic groove long, well developed, longitudinal. From front, anterior eye row slightly recurved, almost straight, posterior row recurved; from above, anterior row slightly recurved, posterior row straight; AME circular, dark; PME irregularly circular, light; lateral eyes oval, light; eyes almost subequal; AME separated by their diameter or more, by slightly less to slightly more than their diameter from ALE; PME separated by slightly more their diameter, and by at least twice their diameter from PLE; lateral eyes of each side separated by their diameter or more; MOQ slightly longer than wide, roughly rectangular, often shallowly narrowed anteriorly; clypeal height equal or greater than AME diameter. Chelicerae (Murphy 2007: figs p. 232, 234) convex anteriorly near the base, with small lateral condyle, partly hidden under the carapace; three discrete promarginal teeth, apical and medium large, subequal or apical very slightly smaller, basal mostly weaker, sometimes minute, situated just near medium tooth; two discrete and large retromarginal teeth, separated much as the apical and medium promarginal teeth; in males, chelicerae often more elongated, laterally slightly more convex in the middle, fang longer, teeth smaller, especially apical of each margin; chilum triangular, partly divided. Endites slightly depressed in females, more in males, straight, parallel, with long internal distal scopula and weak external distal serrula; labium roughly square or slightly longer than wide; sternum shield-shaped, with dark setae covering entire surface, weakly rebordered, with short extensions to and between coxae; trochanters only shallowly notched. Leg formula 4123 in female, 1423 in male. Typical leg spination pattern (only surfaces bearing spines listed): femora: I, II d1-0-0; I p0-0-1; II p0-1-1; III, IV d1-1-0; III p0-1-1, r0-0(1)-1; IV r0-0-1; tibiae: I v1 p-2-0; II v0-1p-0; III, IV p1-1, r1-1; III v1 p-1p-2; IV v2-2 -2; metatarsi: I, II v2 -0-0; III, IV p1-2-2; III v2 -0-2, r0(1)-2-2; IV v1 r-1p-2, r1-2-2. Metatarsal preening comb lacking, but presence of a distal preening brush under metatarsi of both posterior legs. Metatarsi I and II and all the tarsi thickly scopulate, tibiae I and II weakly scopulate, often only the prolateral side, between the median spine(s) and the tip. Tarsi with two weakly pectinate claws and with claw tufts. Tarsi and metatarsi of the first pair of male legs ventrally with a series of long sensitive setae, retrolaterally directed. Palpal femur with 1 dorsomedial spine and 1 dorsodistal spine, often a second spine in prolateral position. Abdomen (Murphy 2007: figs p. 232, 234) usually pale to dark grey, sometimes with an inconspicuous darkened cardiac mark and dots, and with conspicuous anterior tuft of hairs; venter same colour or lighter, with two closely spaced longitudinal rows of dark spots, beginning behind the epigastric fold, and two short wider spaced rows, beginning in front of the anterior lateral spinnerets; males without dorsal scutum. Six spinnerets (Fig. 1; Murphy 2007: figs p. 232–235), ALS large, cylindrical, separated by slightly less than their diameter, apically with two major ampullate gland spigots and with eleven to sixteen piriform gland spigots, situated around the edge and middle of the spinneret tip; a pair of small sclerotized crescent, from which emerges a fringe of closely spaced and thin setae, is present on the ALS, on the prolateral and retrolateral sides of the tip of those spinnerets; PMS are the smallest, apically with minor ampullate gland spigots (two in female, one in male) and numerous aciniform gland spigots, and subapically, on the posterior side, with five cylindrical gland spigots, exclusively in female; PLS are smaller and narrow than the ALS, apically with one minor ampullate gland spigot, two cylindrical gland spigots, exclusively in female, and numerous aciniform gland spigots.
Male palp. RTA bifid (Figs 5, 9, 13, 23, 27, 31, 44, 48, 52), inferior prong lamellar, rounded, often blunt, sometimes absent (D. fritillifer only, Fig. 37); superior prong more sclerotized and sharp, regularly curved, cat-claw shaped (Figs 13, 23, 27, 37, 44, 48, 52) or sometimes almost straight (Figs 5, 9, 31), often longer than inferior prong. In ventral view, the embolus, arising mesally, is long and corkscrew-shaped, and is associated for almost its entire length with a haematodocha, together forming a huge coiled structure (Figs 4, 8, 12, 22, 26, 30, 43, 47, 51), which spirals upwards either along one axis (Figs 12, 22, 26, 30) or two axes (Figs 4, 8, 43, 47, 51); sometimes the embolar coil is very compact and twisted (D. fritillifer only, Fig. 36); terminal part of the coil is either simple or provided with an enveloping scoop-shaped embolar apophysis, projecting forward (Figs 4, 8, 47, 51). Median apophysis arising near the embolar coil, stout and hook-shaped, either pointing inwards or prolaterally (D. fritillifer only, Fig. 36).
Epigyne. Epigynal atrium often very deep, higher than wide to strongly wider than high (0.28–0.71 wide, 0.23–0.64 high, ratio 0.80–1.91) (see Table 1 for details), variously shaped; atrium bordered with slightly sclerotized and often very curved lateral margins, which are notched near the epigastric furrow, forming sockets (Figs 2, 10); lateral margins converging anteriorly to a variously shaped hood-like arch, simply convex or straight (Figs 16, 20, 24) or often provided with a tongue-shaped (Figs 2, 6, 10, 14, 18, 28, 32, 34, 39, 41) or tubercle-shaped projection (Figs 45, 49, 53, 55); lateral margins connected posteriorly by a thin and slightly chitinized ridge; copulatory openings situated anteriorly, separated by a thin to large septum, often partially hidden by the anterior arch or tongue when viewed from above, but easily visible from a posterior view (Fig. 2); membranous coils wide and very high, corkscrew-shaped much as the embolar coils of the male palps, associated with long and thin coiled ducts, which are connected posteriorly to flattened lanceolate structures and distally to very small bursae (Figs 3, 11); major part of the coiled ducts situated inside the membranous coils (axial, spiral-column shaped) (Figs 11, 15, 17, 19, 21, 25, 29, 33) or joined with the outer walls of these coils (external, peripheral) (Figs 3, 7, 35, 40, 42, 46, 50, 54, 56).
Remarks about the structures and the functions of the genitalia. The recent overview of the gnaphosid genera by Murphy (2007) shows the high diversity of genitalic structures occurring in the family. Among these genera, the genitalia of the genus Drassodex appear singular, atypical, the males having huge corkscrewshaped embolar structure which enter the equally corkscrew-shaped internal structure of the females; the illustrations of this paper clearly show, for each species, that the male coils closely match the female coils.
The mechanism of the introduction of the male coil inside the female had been studied by M. J. Roberts, who artificially expanded a male palp of D. cervinus in hot lactic acid. It appeared that three haematodochae are implicated in this mechanism: a basal haematodocha, in the cymbium, which pushes out and rotates the palpal organs; a middle one, which pushes the median apophysis out to the side and the more distal organs further; and a distal one, which fills the entire length of the coil carrying the embolus. The embolus itself lies in the “upper” edge of the coil and emerges as a free structure near the tip. The distal haematodocha is found as a distensible membrane on the inner surface of the coil. When expanded, this latter pushes out, swells and partially uncoils the embolus. The median apophysis is a hook structure lying just below the coil and must probably engage in the postero-lateral sockets of the female epigyne, allowing a firm grip. To summarize, the whole coiled male embolus is inserted through the coil of the epigyne, mechanical stability being provided by the median apophysis hooking into the postero-lateral epigyne socket. Finally, if this inference is correct, the free embolus tip should reach somewhere near the apex of the female coil, where the sperm is hence discharged.
Concerning the female, two independent investigations were carried out by two of the authors to describe the structure of the vulva (i.e., the dorsal view of the epigyne). In entelegyne spiders, the vulva is typically constituted by a pair of seminal receptacles, commonly called spermathecae, associated with two pairs of ducts, one connecting the copulatory openings to the spermathecae, which permit to transfer the sperm by the introduction of the embolus, the insemination ducts, the other pair connecting the spermathecae to the oviduct, the fertilization ducts. Following, in part, the interpretation of Wiehle (1967: 13), one can think that the very small bursae attached near the distal part of the large coils of the epigyne are the spermathecae, and the highly visible, narrow, coiled ducts, running back from these spermathecae to the flattened lanceolate structures, are the fertilization ducts. The insemination ducts, connecting the apex of the large coils to these small spermathecae, had not been found with classical observation; we can thus hypothesize that they are probably minute or transparent, perhaps sometimes hidden by the dark secretions often observed in the inseminated females. Another interpretation can be proposed for the structures above-mentioned. Indeed, the small bursae can be seen as some glandular organs rather than some seminal receptacles. This hypothesis was proposed by Grimm (1985). Regarding this opinion, and considering that the sperm is discharged near the apical part of the large coils of the female (indicated by the presence of the dark secretions, presumably equivalent to a “plug”, Figs 34, 46, 56), the spermathecae could then be located in this latter area, but not clearly identified at this time. An hypothesis was then made that the spermathecae could correspond to the slight enlargements, sometimes observed of the apical part of the narrow coiled ducts (see vulva of D. hypocrita, Fig. 7), or maybe even correspond to the entire length of these ducts, implicating consequently that of the spermathecae is not globular but tubular receptacles! (Note that Grimm located the spermathecae only as the proximal part of this duct, near the epigastric furrow, see “R” in fig. 127). Complementary, the membranous large coils is hence considered as the copulatory openings (Grimm 1985) or the insemination ducts, the small bursae are some anterior glandular groups (Grimm 1985; Ledoux 1997) (a preliminary microscope examination seems reveal discrete gland ducts), the narrow coiled ducts is considered, in part or in totality, as the spermathecae, and the flattened lanceolate structures is considered as the fertilization ducts (Grimm 1985; Ledoux 1997).
Without investigation in the fine observation of the ultrastructure of the female genitalia, it was decided to name the different parts of the vulva without connotation about their functions, by the following terms: the copulatory openings, the membranous coils, the coiled ducts, the small bursae and the flattened lanceolate structures.
Relationships of Drassodex. In a recent proposition for a new arrangement of the gnaphosid genera of the world, Murphy (2007) erected the genus Drassodex to receive the species of the Drassodes hypocrita -group of Simon (1914) (D. vinosus excluded). Indeed, although the species belonging to Drassodex possess some features also observable in Drassodes (presence of notched trochanters, similar cheliceral dentition and lack of a dorsal scutum on the male abdomen), a special feature of the ALS was employed to unite Drassodex with the genera Anagraphis Simon, 1893 and Talanites Simon, 1893, all three forming the informal Anagraphis - group (Murphy 2007). The feature of the ALS concerned is the presence of a sclerotized annular crescent, bearing thin setae, on both the prolateral and retrolateral sides of the spinneret tip, situated between the sclerotized edge of the basal segment and the area of the piriform gland spigots (Fig. 1; Murphy 2007: figs p. 233, 235). This character is unique among the family Gnaphosidae (Murphy 2007) and it presumably represents a remnant of the sclerotized distal segment of the ALS, which is present in the more plesiomorphic gnaphosoid families and their outgroups (Platnick 1990; Platnick & Baehr 2006). Two other remarkable features, also presumably plesiomorphic in gnaphosids (Platnick 1990), are observable in the Anagraphis - group: the presence of some piriform gland spigots in the middle, rather than exclusively around the edge, of the ALS tip (only observed in Drassodex and Talanites) and the general shape of these spigots, which differ from the typical form seen in most gnaphosid genera (Murphy 2007). Consequently, the Anagraphis -group seems to be united only by plesiomorphic features, and hence is potentially a non-natural (i.e., nonmonophyletic) group. However, as pointed out by Murphy (2007), these genera share some similar somatic and genitalic features, as the configuration of the male palp (coiled embolus in Drassodex and Anagraphis pallens Simon, 1878), the shape of the RTA (bifid), the eye pattern (in particular the subcircular PME) and the cheliceral dentition pattern (three discrete teeth on the promargin, two on the retromargin.). Until new considerations, the genus Drassodex is hence considered as closest to the genera Anagraphis and Talanites.
Relationships between the species. Examination of the genitalic characters of the members of Drassodex allowed us to associate some of them into two hypothetically monophyletic groups: one of these groups includes D. hypocrita, D. lesserti, D. validior and D. granja sp. nov. These species exhibit the same shape of male embolar coil, with the distal loop very much narrowed and shifted more retrolaterally than the basal loop, spiralling upwards along a different axis (Figs 4, 8, 43, 47, 51), the presence of a terminal embolar apophysis (in the first three species only, absent in D. granja), and the position of the coiled duct, joined with the outer walls of the membranous coil (Figs 3, 7, 42, 46, 50, 54, 56). The second group includes at least D. heeri, D. drescoi sp. nov. and D. simoni sp. nov., all these species having a regularly looped male embolar coil, the distal loop large and positioned in the same axis as the basal loop (Figs 12, 22, 26, 30), the tip of the embolar coil very simple, only attenuated or truncated, without terminal apophysis, and the position of the coiled duct, running freely inside the longitudinal axis of the membranous coil (Figs 11, 15, 17, 19, 21, 25, 29, 33). These three species occur only in and around the Alps. We can probably bring closer D. cervinus (Pyrenees and Spain) to these species, based on the great similarity in their genitalia (regular male embolar coil, Fig. 30, and female spiral-column coiled duct, Fig. 29); this latter species is hence presumably a vicariant of the former species. It is not easy to define the affinities of the two similar species D. hispanus and D. fritillifer with the others, but the coiled duct, which is apparently joined to the outer walls of the membranous coil (Figs 35, 40), seems to be much closer to the first group than that of the second one.
Distribution. Considering the great number of misidentifications encountered in the MNHN collection, we can suppose that similar mistakes occurred in other European collections, and subsequently in catalogues or faunistic studies. It could be particularly the case for the species described under Drassus (D. hispanus, D heeri, D. hypocrita). Nevertheless, representatives of Drassodex mainly occur in south-western Europe, especially in and around mountain systems, at medium to high elevations: D. cervinus is recorded from the Pyrenees and north-eastern Spain, D. fritillifer from the Pyrenees and eastern Spain, D. heeri, D. drescoi sp. nov. and D. simoni sp. nov. from the Alps, D. hispanus from central and eastern Spain, D. granja sp. nov. from central Spain, D. validior and D. lesserti from western Alps and South France. The most widely distributed species is apparently D. hypocrita, recorded from France to West part of Russia, at lower to medium elevations.
description: Published as part of Hervé, Christophe, Roberts, Michael J. & Murphy, John A., 2009, A taxonomic revision of the genus Drassodex Murphy, 2007 (Araneae: Gnaphosidae), pp. 1-28 in Zootaxa 2171 on pages 3-8, DOI: 10.5281/zenodo.189206