Atmetochilus fossor Simon 1887
Creators: name: Kunsete, Chawakorn
name: Sivayyapram, Varat
name: Traiyasut, Prapun
name: Thanoosing, Chawatat
name: Khamwan, Kitiwat
name: Warrit, Natapot
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Nemesiidae
Atmetochilus
Atmetochilus fossor

description: Atmetochilus fossor Simon, 1887
(Figs 1C, 6, 9 G–I, 10C–D, 11A, Table 3)
Atmetochilus fossor Simon, 1887: 109; 1892: 109, 65 (fig. 73).
Type. Holotype, female from “Tavoy, Burma”, = Dawei, Myanmar; putatively in Zoological Collection of the Indian Museum, unavailable, presumed lost. We also confirm this information from the e-mail of Mrs Shelley Achaya, the curator in ZSI who said, “The other one (= A. fossor) is not available in the NZC of Arachnida section, ZSI”.
♀ Neotype. [(ARA-2018-132) 4/5/2018]— Tavoy, 14°6.279’ N; 98°18.007’ E, altitude: - 1 m Warrit N., Kunsete C., Sivayyapram V., Nawanetiwong W., CUMZ.
Material examined. Myanmar: Tavoy, 14°6.279’ N; 98°18.007’ E, Altitude: - 1 m Warrit N., Kunsete C., Sivayyapram V., Nawanetiwong W., ♀ [(ARA-2018-125) 4/5/2018], ♀ [(ARA-2018-127) 4/5/2018], ♀ [(ARA-2018128) 4/5/2018], ♀ [(ARA-2018-129) 4/5/2018], CUMZ.
Diagnosis. Females are large spiders that differ from other species by the reddish carapace. Females further differ from those of A. atriceps by the scopula on metatarsus I extending for the full length, but the scopula on metatarsus II only for the distal half and by the spines on the prolateral patella and femur of palp, and of legs I and II (for scopula and spine character comparison; see Figs 9 D–L and 10A–F). They differ from those of A. koponeni, A. lehtineni and A. sumatranus by the medial pair of sigilla being fused with the posterior pair. and the spermathecae has a spherical head (without such a head in A. koponeni, A. lehtineni) and not dome-shaped as in A. songsangchotei sp. nov.
Description. Female (Neotype, ARA-2018-132, CUMZ): Body (Fig. 6A), length 25.
Color in nature: Carapace red. Chelicerae and all legs dark brown. Upper abdomen grey with pale white spots and ventral abdomen white.
Color in alcohol: Carapace red. Chelicerae and legs dark brown. Upper abdomen grey with pale spots and similar on ventral abdomen.
Carapace (Fig. 6B): 10.60 long, 8.75 wide. Chelicerae 4.38 long. Eyes (Fig. 6C): tubercle with 2 rows on low mound, 4 eyes in each row. Anterior row procurved, posterior row slightly recurved. Eye sizes and interdistances: AME 1.30, AME-AME 0.50, ALE 1.60, ALE-ALE 4.40, PME 1.00, PME-PME 2.90, PLE 2.90, PLE-PLE 4.70, AME-ALE 1.00, AME-PME 0.30, AME-PLE 1.00, ALE-PME 1.00, ALE-PLE 1.80, PME-PLE 0 (contiguous). Eye to fovea 6.88. Fovea (Fig. 6B): strongly procurved to U-shaped, medially straight. 3 rows of setae in fovea. “Rastellum” of about 15 robust down-curved setae on anterior margin of chelicerae. Cheliceral furrow with 7 promarginal teeth and mesobasal denticles present. Fang ventrally smooth without teeth. Stridulating strikers absent. Labium (Fig. 6D): labium 1.50 long, 1.20 wide without cuspules. Maxillae (Fig. 6D) 4.25 long, 2.00 wide with 42 tiny cuspules each on proximal anterior lobe. Sternum (Fig. 1C): 5.16 long, 4.50 wide. Posterior and medial sternal sigilla centrally confluent, anterior sigilla small in upper margin.
Spination: Palp: tibia, v3, patella, p1, tibia, p1, tarsus scopula on venter, v2. Leg I: femur, p1, patella, p1, tibia, v2, metatarsus scopula cover entire but thin at base, tarsus scopula cover entire, without spines. Leg II: femur, p1, patella, p2, metatarsus scopula on its distal half, v2 p1, tarsus scopula cover entire. Leg III: patella with group of around 10 short hard setae on dorsal, tibia, v1 r2 p4 d1, metatarsus with 21 spines, v3 r4 p8 d6, palp without scopula and spine. leg IV: patella with many short hard setae on dorsal as same as femur, tibia, v3 p1, metatarsus has 15 spines, v3 r3 p9. Preening combs on distal ventral of metatarsi II–IV. Legs (Table 3), formula: 4123.
Scopula: entire on tarsus of palp and metatarsus I, relatively short, sparse cover on distal half on metatarsus II, absent on tarsi III and IV, metatarsi III and IV, tibiae and femora I–IV.
Trichobothria: one zigzag row of 8–14 on tarsi I–IV, one row of 6–16 on metatarsi I–IV and two rows, each of 5–8 on tibiae I, III.
Claw: 1 row of teeth on prolateral edge of palpal claw. 2 rows of teeth on both paired claws of legs I–IV but different number including 3 teeth on inner side, 5–7 teeth on outer side of leg I, 2 teeth on inner side, 5–6 teeth on outer side of leg II, 2 teeth on inner side, 3 teeth on outer side of leg III and one tooth on inner side, 3 teeth on outer side of leg IV.
Spermathecae (Fig. 11A): head of spermathecae spherical with cap darkly sclerotized, stalk 0.7 mm, base 1.1 mm stalk base wider than tip.
Spinnerets: PMS: 1.20 long, diameter 0.15. PLS: 2.52 long, 0.20 diameter, length of basal, medial and apical segments 1.20, 0.60, 0.72; apical segment digitiform.
Distribution. Known only from type locality Dawei (Tavoy), Myanmar.
Remarks. The neotype designation is made because the original description and figures are far too inadequate and imprecise to allow the correct species identification and the type is presumed lost.
From field collecting in Dawei, Myanmar, from 2–4 May 2018. We found 8 individuals of Atmetochilus including 3 females and 5 juveniles. They lived in burrows on the roadside bank (Fig. 2B) and their populations were aggregated with each other. We diagnosed it as A. fossor by carapace color, size and scopula characters. The stated type locality was Tavoy, Burma; this is now spelt Dawei.
description: Published as part of Kunsete, Chawakorn, Sivayyapram, Varat, Traiyasut, Prapun, Thanoosing, Chawatat, Khamwan, Kitiwat & Warrit, Natapot, 2020, Records and redescription of a mygalomorph spider genus ignored for over 100 years with a new species: the genus Atmetochilus Simon, 1887 (Araneae Nemesiidae) in Thailand, pp. 521-543 in Zootaxa 4819 (3) on pages 531-532, DOI: 10.11646/zootaxa.4819.3.5, http://zenodo.org/record/4397082