Coelotes atropos (Walckenaer)

WANG, XIN-PING, 2002, A Generic-Level Revision Of The Spider Subfamily Coelotinae (Araneae, Amaurobiidae), Bulletin of the American Museum of Natural History 2002 (269), pp. 1-150 : 6-19

Coelotes atropos (Walckenaer)

No coelotine has ever been described in detail. A representative species, Coelotes atropos , which is a relatively common European species and the type species of the genus Coelotes , was chosen here for detailed description.

Body form (fig. 5): Ecribellate spiders. Total length about 9.00–12.0 (female) and 8.00–9.50 (male). Carapace elongate, reddish brown, moderately narrowed in ocular area, sparsely covered with short, long black setae; few strong setae on clypeus, ocular area, and middle carapace; longitudinal fovea moder­ ately depressed. Legs moderately long, strong. Abdomen dark brown, with dark maculation, heavily covered with short setae. Spinnerets moderately elongated.

Eyes (fig. 6): From front, anterior eye row slightly procurved, posterior row procurved; eye sizes and arrangements: AME smaller than ALE, ALE slightly larger than PLE, PME subequal to PLE, slightly larger than AME; AME may be separated by their diameter or slightly less than their diameter, AME­ALE slightly shorter than AME­AME, PME separated by their diameter, PME­PLE widely separated by 1.5–2.0 PLE diameter, lateral eyes close together; AME­PME separated by PME diameter.

Clypeus (fig. 6): Height two times AME diameter, covered with long, strong setae; chilum divided, hairless.

Chelicerae (figs. 6–8, 12–19): Three promarginal teeth, with middle one largest, and three retromarginal teeth, subequal in size (fig. 8); condyle large (figs. 7, 8); cheliceral glands open distally near base of fang on both dorsal and ventral sides, gland openings situated inside striated grooves (figs. 13, 14); dorsal chelicerae covered with long setae, with strongly elevated base (figs. 6, 7); chelicerae ventrally flat, with proximal short setae and inner long, fine setae (figs. 8, 12, 15, 16); fangs moderately long (figs. 8, 18, 19); venom gland large, reaching middle of thorax; anterior face of chelicerae covered with dense, long, strong setae (figs. 8, 17).

Endites (fig. 9): Rectangular, with anterior scopula and linear serrula.

Labium (fig. 9): Rectangular, slightly longer than wide, slightly notched distally.

Sternum (fig. 11): Shield­shaped, sparsely covered with long dark setae (setae not in figure), heavily sclerotized.

Legs (figs. 20–30): Legs medium to long. I, IV longest, almost subequal, leg III shortest; length of 1st leg patella+tibia shorter than carapace length; trochanters not notched or with very weak notch; tibiae with about four rows of trichobothria; metatarsi and tarsi with one row of trichobothria, their length gradually increasing distally; trichobothria with large hoods transversely striated, small hoods smooth. Tarsal organ situated close to distal end of tarsus, slightly anterior of most distal trichobothrium. Tarsi with three claws, superior tarsal claws with 10–12 teeth, inferior tarsal claws usually with 2–3 teeth; scopulae absent; leg spination often varies among individuals, typical leg spination pattern: femur: I p0–0–2, d1–1–1(0); II p0–0–1, r0–0– 2, d1–1–1(0); III p0–1–2, r0–0–1, d1–1–0; IV p0–0–1, d1–1–0; patella: p1(0), r1(0), d1(0); tibia: I p0–0–0(1), r0–0–2, v2–2–2; II p1–1–0, v2–2–2; III, IV p1–1–0, r1–1–0, v2– 2–2; metatarsus: I p0–0–0(1), v2–2–2; II p0– 1–2, v2–2–2; III p1–2–2, r1–2–2, v2–2–2; IV p1(2)­2–2, r1(2)­2–2, v2–2–2; tarsus: III, IV p1–1–0, r1–1–0.

Trachea (fig. 31): Simple, limited to abdomen; median spiracle situated close to spinnerets and connected to relatively narrow atrium from which two lateral and two median tubes arise.

Spinnerets (figs. 32–37): Colulus absent; ALS cylindrical, apex of ALS with 2 major ampullate gland spigots (MAP) at mesal margins, 15–30 piriform gland spigots; PMS with spigots situated on distal half of segment, both sexes PMS with 1 or 2 minor ampullate gland spigots (mAP), 30–50 aciniform gland spigots (AC), female PMS with 2 cylindrical gland spigots (CY); PLS with second segment about same length as first segment, with 30–40 aciniform gland spigots in both sexes, and 2 cylindrical gland spigots in female.

Female genitalia (figs. 38–43): Epigynal teeth short, situated on lateral atrium; atrium reduced to atrial slits; copulatory ducts short; spermathecal heads short, broad, situated anteriorly; spermathecae longitudinally elongated with indistinct stalks and bases.

Male genitalia (figs. 44–54): Palpal femur long, with three strong spines dorsally, femoral apophysis absent; patella short, with long, strong dorsal spine; patellar apophysis broad; tibia short, almost same length as patella, with three conspicuous strong spines on prolateral side; retrolateral tibial apophysis (RTA) extended along tibia length, with distal end slightly extended beyond tibia; a small apophysis, called lateral tibial apophysis here, arises from tibia retrolaterally on dorsal side of RTA, and differs both in morphology and position with the dorsal tibial apophysis in other taxa, such as some phyxelidine species ( Griswold, 1990) and amaurobiid species (Leech, 1972); cymbium long, strongly extended anteriorly beyond alveolus, with many conspicuous, long spines on distal and prolateral surfaces; cymbial furrow short, less than half cymbial length, with dorsal edge slightly concave; a rectangular sclerotization of the distal tegular surface, called tegular sclerite here, is present and unique for coelotines; treated tegular sclerite as radix ( Bennett, 1987) was not appropriate because radix usually refers to the proximal segment connecting the embolus to the tegulum (Gering, 1953; Comstock, 1910); conductor short; an apophysis arises dorsally on the conductor, which has been described as terminal apophysis ( Bennett, 1987), is here called the conductor dorsal apophysis; terminal apophysis often related to embolus rather than to conductor ( Comstock, 1910; Sierwald, 1990); conductor dorsal apophysis broad, with rough surface; conductor lamella moderately developed; embolus moderately long, prolateral in origin; median apophysis spoonlike, short, rounded, with smooth distal end.

COELOTINAE GENERAL MORPHOLOGY

Within coelotines, both male and female somatic structures are relatively uniform; this condition offers few characters for identification and phylogenetic analysis of species and genera. However, a few characters vary within coelotines, as discussed here.

Eyes: Coelotines often have AME smaller than ALE. AME are much smaller than ALE (e.g., Bifidocoelotes , fig. 90) or slightly smaller (e.g., Himalcoelotes martensi , fig. 270). In Coras, AME are larger than ALE (fig. 147).

Cheliceral teeth: In most coelotines, the promargins of the chelicerae are relatively constant with three teeth, but in Leptocoelotes , Robusticoelotes , and Spiricoelotes , there are more than four teeth (figs. 301, 356, 365). The cheliceral retromargin varies from two (e.g., Ambanus and Wadotes , figs. 63, 418) to three (e.g., Coelotes and Paracoelotes , figs. 8, 329), four (e.g., Coronilla and Leptocoelotes , figs. 170, 301), or even more than five teeth (e.g., Robusticoelotes and Spiricoelotes , figs. 356, 365).

Trichobothria and tarsal organ: The distribution of trichobothria in coelotines is like that of C. atropos . The tarsal organ is usually situated close to the distal end of tarsus and anterior to the most distal trichobothrium (as in most coelotines, figs. 28, 172, 391). However, there are variations. In examined species of Draconarius , the tarsal organ is situated far from the distal end and close to the second most distal trichobothrium or even farther proximally (figs. 186, 202); in Femoracoelotes (figs. 234, 235), the tarsal organ is near the third most distal trichobothrium; in Leptocoelotes , it is near distalmost trichobothrium (figs. 305, 306). The tarsal organ was not seen in examined specimens of Platocoelotes (figs. 343, 345).

Spinnerets: The types of spigots are constant in coelotines, but the number varies among genera and species and between sexes: the number of piriform gland spigots on the ALS varies from about 15 to 110, and the number of aciniform gland spigots on the PMS and PLS also varies from 20 to 120; both the PMS and PLS usually have 2 cylindrical gland spigots, but Paracoelotes has 3 or 4 cylindrical gland spigots on PMS (fig. 334), and 3 cylindrical gland spigots were seen on Ambanus PLS (fig. 66).

COELOTINAE GENITALIC MORPHOLOGY

Female

In Platocoelotes , the sclerotized epigynum is strongly enlarged to occupy most of the front epigastric furrow (fig. 336). In Coronilla , the posterior margin of the epigynum is strongly expanded posteriorly (figs. 158, 159). The epigynum is characterized by the atrium, epigynal teeth, and epigynal hoods.

Atrium: The atrium here refers to the con­ cavity on the epigynum plate which leads to the copulatory ducts of the vulva. It may be large (e.g., Ambanus and Paracoelotes , figs. 57, 323) or merely an atrial slit (e.g., Wadotes and Asiacoelotes , figs. 410, 70). In most coelotines, the atrium is situated medially or more or less anteriorly on the epigynal plate, but in Coelotes rufulus ( Wang et al., 1990) , the atrium originates posteriorly on the tonguelike posterior extension of the epigynum. The anterior atrial margin may be strongly extended posteriorly, as in Tonsilla and Paracoelotes (figs. 384, 323). In Coronilla , the middle part of the atrium may form a transverse carina (figs. 158, 159). In most coelotines, the lateral atrial margins are more or less parallel and widely separated, whereas in Coras , the lateral atrial margins are more widely separated anteriorly than posteriorly and enclose a vase­shaped area (figs. 137, 139, 141, 142).

Epigynal teeth: These are present in most coelotines but absent in some (e.g., Coronilla and Longicoelotes , figs. 158, 310). There may be a single, medially situated epigynal tooth, as in Bifidocoelotes and Wadotes (figs. 86, 410), or teeth may be paired (most coelotines). If present, it or they may be extremely long (e.g., Himalcoelotes and Urocoras , figs. 265, 400), broad (e.g., Leptocoelotes and Tegecoelotes , figs. 296, 375), or slender. In Asiacoelotes , epigynal teeth occur anteriorly on epigynal plate (fig. 70), whereas in Tonsilla , epigynal teeth are located close together on the anterior atrial margin (fig. 384).

Epigynal hoods: These are a pair of small, sclerotized, hairless plates that are usually situated laterally on the epigynal plate (e.g., Ambanus , fig. 57). In Platocoelotes (fig. 336), however, the hoods are located posteriorly and close to the epigastric furrow. A pair of large muscles, which are attached inside the hoods, may be important in female genitalic movement during copulation. The hoods can be either strongly depressed, as in Spiricoelotes (figs. 360, 362), or only moderately depressed.

Fertilization ducts: These are very small in all coelotines and arise from the posterior end of the spermathecae.

Copulatory ducts: These are usually membranous and may be large and broad (e.g., Paracoelotes , fig. 324) or small (e.g., Tegecoelotes , fig. 376). The copulatory ducts may originate anteriorly, as in most coelotines, or posteriorly as in Draconarius (figs. 182, 193).

Spermathecae: These are the structures be­ tween copulatory ducts and fertilization ducts. The spermathecae can be either strongly elongated as in Asiacoelotes (fig. 71), strongly elongated and highly convolut­ ed as in many Coras species (figs. 138, 140), or short and simple as in Coelotes (fig. 39). Many coelotines possess more or less complex spermathecae of three distinct parts: spermathecal heads, stalks, and bases. Spermathecal heads are the apical, dilated parts of the spermathecae that connect to the spermathecal bases through the spermathecal stalks; they arise near the copulatory ducts and are usually situated anteriorly (figs. 324, 376); the size varies between species. Spermathecal stalks may be elongated, convolut­ ed, and distinct from their bases (e.g., Coras , fig. 138). However, in many coelotines, stalks may be short or indistinct from the ba­ ses (e.g., Paracoelotes , fig. 324), which themselves are highly sclerotized, slightly convoluted, and dilated relative to the stalks.

Male

Femur: The femur has, in most coelotines, three distinctive strong spines dorsally (figs. 47, 48). In Eurocoelotes gasperinii ( Simon, 1891) , 5 or 6 short strong spines arise only distally and 1 arises medially. Most coelotines have no femoral apophysis, but in Femoracoelotes a femoral apophysis arises distally (figs. 229, 230), and prolaterally there is cluster of numerous short, strong setae (fig. 231).

Patella: In Tegecoelotes , the patella is elongated to at least twice the tibial length (figs. 377–380). A long strong spine always arises distally on the dorsal patella, and most coelotines have a relatively short spine proximally (figs. 45, 403). A patellar apophysis may be absent (e.g., Ambanus , fig. 60) or may vary in number from one (as in most coelotines, figs. 146, 313), two (as in Coronilla , figs. 162, 165, 168), to three (as in Robusticoelotes , figs. 353, 354). The apophysis may be small (as in Paracoelotes , fig. 326) or broad (as in Coelotes , figs. 45, 49). In the Coelotes charitonovi species group, the patellar apophysis is large, broad, and strongly modified (fig. 118). In Spiricoelotes , the distal part of the apophysis is sharply bent dorsally (fig. 368). In the genus Longicoelotes , the apophysis is strongly elongated, longer than the tibia (fig. 313).

Tibia: The tibia is short, almost the same length or slightly longer than the patella. The retrolateral tibial apophysis (RTA) usually occupies most of the tibia. In Paracoelotes tianchiensis ( Wang et al., 1990) , the tibia is very long and the RTA occupies only onefourth to one­fifth of the tibial length. The tip of the RTA varies between species: it can be blunt, only slightly extended (fig. 368), or strongly extended anteriorly (fig. 378). Lateral tibial apophyses are present in most coelotines, with the size ranging from large (e.g., Tegecoelotes , fig. 378) to small (e.g., Leptocoelotes , fig. 304) or absent (e.g., Coronilla and Femoracoelotes , figs. 162, 168, 230). In Ambanus (fig. 60) and Wadotes (fig. 413), the lateral tibial apophysis is located distally on the tibia and is strongly modified into a small concavity. In Robusticoelotes (fig. 354) and some species of Coras (figs. 144, 146), the retrolateral tibial surface is also strongly modified. Three strong spines always occur on the prolateral tibial surface (figs. 46, 49, 412).

Cymbium: The retrolateral side of the cymbium is modified into a cymbial furrow in all coelotines. Similar furrows are also present in other spider families, such as Campostichomma Karsch, 1891 ( Miturgidae , see Griswold, 1993) and Mallinella Strand, 1906 ( Zodariidae , see Wang et al., 1999), but with quite different palpal structures and apparently not closely related. The coelotine cymbial furrow may be short and shallow (e.g., Ambanus , Coronilla , and Longicoelotes , figs. 60, 162, 314) or strongly elongated to more than half the cymbial length, with a strongly concave dorsal edge (e.g., Asiacoelotes and Bifidocoelotes , figs. 73, 89). In all coelotines, three to six strong spines occur on the ventral distal cymbium, and four to six strong spines occur on the prolateral cymbium (figs. 44, 49), although they are not always so strong as the distal spines. In Wadotes , the basal cymbium bears retrolateral and prolateral apophyses (figs. 412, 414, 415). Trichobothria are usually absent on the cymbium, but many Himalayan species of both the genus Himalcoelotes and Draconarius have a row of two to five trichobothria on the retrolateral side, just anterior to the cymbial furrow.

Basal hematodocha, subtegulum and me­ dian hematodocha: All coelotines possess a large basal hematodocha with a well­developed petiolus on the retrolateral side (figs. 49, 167). The subtegulum is sclerotized, funnel­shaped, and contains the fundus of the sperm duct and three to five anelli prolaterally (figs. 49, 166); distally it is highly sclerotized. A short and relatively indistinct median hematodocha connects the distal subtegulum to the tegulum (fig. 49).

Tegulum: The tegulum and its structures differ considerably among species and genera. The ringlike wall of tegulum is highly sclerotized. The distal inflatable surface of the tegulum is relatively membranous and houses some distinct structures, namely the tegular sclerite, conductor, embolus, and median apophysis.

Tegular sclerite: In most coelotines, the tegular sclerite is simple, but some speciesspecific structures do occur. In Asiacoelotes xinhuiensis , a small sharp apophysis arises from its retrolateral side (fig. 72). In some Coras species , the anterior tegular sclerite is prolaterally expanded and forms a broad apophysis (fig. 143). In Ambanus , the tegular sclerite is weakly sclerotized (fig. 59).

Conductor: This arises prolaterally on the anterior tegular sclerotized ring and is closely associated with the anterior part of the tegular sclerite. The conductor base is usually modified to form a membranous lamella and varies from small and moderately developed (e.g., Coelotes and Paracoelotes , figs. 44, 46, 325), to large and well developed (e.g., Asiacoelotes and Draconarius , figs. 72, 74, 183, 184). The conductor dorsal apophysis may be absent (e.g., Asiacoelotes and Paracoelotes , figs. 73, 326) or present (as in most coelotines, figs. 44, 213). In some Coras species , an apophysis, here called the paraconductor, arises between the conductor and the conductor dorsal apophysis (figs. 143, 144). The paraconductor is similar and parallel to the conductor. In Coelotes atropos , the conductor is very short, whereas the conductor dorsal apophysis is broad and strong (fig. 44). In Draconarius sinualis , both the conductor and its dorsal apophysis are slender and long (fig. 198). The conductor of Paracoelotes is extremely long, flat, spiral, and forms one or two loops, but it lacks a conductor dorsal apophysis (figs. 325, 326). In the genus Wadotes , the conductor dorsal apophysis is strongly modified into a long, toothed process (figs. 413, 414, 416). The conductor is the male palpal structure that varies both in size and shape between taxa.

Embolus: This arises from the posterior tegular ring and is closely associated with the posterior tegular sclerite. The ejaculatory duct of the sperm duct lies inside the embolus. In coelotines, the embolus is usually linear and slender, but it can also be broad and strong (e.g., Ambanus and Robusticoelotes , figs. 59, 351). In most coelotines, the embolus is moderately long (e.g., Coelotes , fig. 44), but it can be very long (e.g., Asiacoelotes , fig. 72). The apex of the embolus usually lies inside the longitudinal groove of the conductor. The embolus may be prolateral (e.g., Coelotes and Eurocoelotes , figs. 44, 213) or posterior in origin (e.g., Asiacoelotes and Spiricoelotes , figs. 72, 367).

Median apophysis: The median apophysis in coelotines is a sclerotized structure located in the retrolateral membranous tegular surface ( Bennett, 1987). In most coelotines, the median apophysis is spoonlike, but it can be either a very small apophysis (e.g., most Longicoelotes , fig. 313) or large but not spoonlike (as in Coronilla , fig. 162). In some species, the median apophysis is absent (e.g., Femoracoelotes ). The spoonlike median apophysis may be rounded with a smooth distal end as in Coelotes (fig. 44) or with a more or less extended distal end as in Paracoelotes (figs. 325, 326). In Himalcoelotes , the median apophysis is small, rounded, medially notched, and strongly extended (figs. 267, 268). In some species, a small tegular carina may be present between the median apophysis and tegular sclerite. In Coras , the tegular carina is well developed and extends either transversely or longitudinally (figs. 143, 144).