Atmetochilus lehtineni, Zonstein & Marusik, 2016

Zonstein, Sergei L. & Marusik, Yuri M., 2016, A review of the Spider Genus Atmetochilus of Sumatra, Indonesia, with First Analysis of Male Characters and Description of Three New Species (Araneae, Nemesiidae), Zoological Studies 55 (10), pp. 1-17 : 7-11

Atmetochilus lehtineni sp. n.

( Figures 2 c-e, 3c,d, 4c,d, 5c,d, 6c,d,e, 7b,c, 8b,c, 9b,c, 10b,c, 11b,c, and 12c,d) urn:lsid:zoobank.org:act:25C136AF-09D7-4439-A771-2765277E43E5

Types: ò holotype (ZMUT) - INDONESIA: Sumatra, Sumalumgun, Pisarani (ca. 2°58'N 99°16'E, 100-200 m), roadside wall, 22.09.1978, P. Lehtinen. Paratypes: 2ñ, 1ñ subad., 2 juv. (ZMUT) - collected together with the holotype; 1ò (SMF 7674) - “ Sumatra ” (no other data).

Etymology: Named after our friend and senior colleague, a prominent Finnish arachnologist Pekka Lehtinen (Turku, Finland).

Diagnosis: The species differs from all other species of Atmetochilus by the following characters: AME is noticeably larger than other eyes (smaller in other species); posterior sternal sigilla smaller and broader spaced from each other vs. larger and confluent). Additionally, A. lehtineni sp. n. may be distinguished from A. fossor and A. atriceps by the presence of cuspules on the labium (vs. unarmed state) and from A. koponeni sp. n. and A. sumatranus sp. n. - by having 5 well developed tegular ridges (cf. Figures 8-11). Males of A. lehtineni sp. n. differ from those of A. bifidus by shorter, stouter and somewhat swollen metatarsus I (longer and uniformly slender in the latter species - cf. Figures 6c,d and Gravely 1935: fig. 1a).

Description: Male (holotype). Habitus as in figures 2c,d. Body length 25.50. Colour in alcohol: carapace and chelicerae uniformly very dark chestnut-brown; labium, sternum, maxillae, palps and legs intensive orange-brown; dorsal abdomen dark brown and densely spotted with numerous small light brown marks, ventral abdominal surface and spinnerets light greyish-brown.

Carapace ( Figure 3c) 9.69 long, 8.38 wide. Eye tubercle and clypeus as shown in figure 4c. Eye sizes and interdistances: AME 0.39 (0.53), ALE 0.33, PLE 0.26, PME 0.21; AME-AME 0.21 (0.11), ALE-AME 0.27 (0.20), ALE-PLE 0.18, PLE- PME 0.10, PME-PME 0.88. Rastellum consists of 10-11 robust and long cone spines. Cheliceral furrow with 8-9 promarginal teeth and ca. 20 mesobasal denticles each. Labium, sternum and maxillae as shown in Figure 5c. Labium 0.93 long, 1.74 wide, with 2 tiny cuspules. Sternum 5.43 long, 4.41 wide. Maxillae with about 15-20 tiny and almost indistinct cuspules each. Palp and leg measurements as shown in Table 3.

Spination: Femora I-III with few dorsal bristles (femur IV also with 4-5 thin basodorsal spines and few dorsoapical spinules), patellae III with few and IV with numerous pro- and retrolateral spinules; palp entirely, patellae I-II and tarsi I-II aspinose. Leg I: tibia p1a, pv0-0-2M, rv1-0-0; metatarsus v0- 1-1-1-2. Tibia and metatarsus I and tibial process carrying megaspines as shown in Figures 6 c-e. Leg II: tibia v1-1-1-0; metatarsus v0-1-2-1-2. Leg III: tibia p1-1, r1-1-1, v1-1-3; metatarsus d2-2-2, p1-1-2-1, r1-1-1, v2-1-2-1-3; tarsus p2, v2. Leg IV: tibia r1-1, v1-1-3; metatarsus d0-0-1-2, p0-1-1, r1- 0-0, v2-1-2-1-3; tarsus p2 v2.

Scopula : dense, distal on metatarsus I; entire on tarsi I and II; vestigial to absent on tarsi III and IV. Paired claws on tarsi I-III with 5-6 teeth in one S-shaped row, on tarsus IV - with basal cluster of 3 teeth and one distant small subapical tooth; unpaired claw moderately small and steeply curved. Trichobothria: 2 rows of 8-10 per row on tibiae, 10-12 on metatarsi, 10-13 on tarsi, 8 on cymbium.

Palp: cymbium aspinose ( Figures 7b,c); bulb with low long carina; tegulum with 5 well developed ventral ridges; embolus curved ( Figures 8b,c, 9b,c, 10b,c, 11b,c).

Spinnerets: PMS: 1.16 long; diameter 0.43. PLS: maximum diameter 0.96; length of basal, medial and apical segments 1.79, 1.07, 1.06; total length 3.92; apical segment short-digitiform.

Female (paratype): Habitus as in Figure 2e. Body length 29.30. Colour in alcohol as in male, but carapace coloured only slighter darker than legs, medium chestnut-brown.

Carapace ( Figure 3d) 9.07 long, 7.32 wide. Eye tubercle and clypeus as shown in figure 4d,e. Eye diameters and interdistances: AME 0.36 (0.50), ALE 0.53, PLE 0.40, PME 0.29; AME-AME 0.16 (0.04), ALE-AME 0.30 (0.22), ALE-PLE 0.16, PLE- PME 0.06, PME-PME 0.85. Rastellum consists of 7-8 very robust and 4-5 more slender long cone spines. Cheliceral furrow with 8-9 promarginal teeth and 20-25 mesobasal denticles. Labium, sternum and maxillae as shown in Figure 5d. Labium 1.20 long, 1.51 wide, with 4 cuspules. Sternum 5.38 long, 4.58 wide. Maxillae with 22- 25 cuspules each. Palp and leg measurements as shown in Table 4.

Spination: Femora I-III with few dorsal bristles (femur IV also with 4-5 thin basodorsal spines and few dorsoapical spinules), patellae III with few and IV with numerous pro- and retrolateral spinules; patellae I-II and tarsi I-II aspinose. Palp: tibia p1-2, v1-1-2; tarsus p1, v2. Leg I: tibia v1-1- 0-0; metatarsus v1-1-1-1-3. Leg II: tibia v1-1-0-0; metatarsus v1-2-1-3. Leg III: tibia p4(3), r1-1, v1- 1-3; metatarsus d12(10), p8(5), r5, v ca. 15; tarsus p4, v1. Leg IV: tibia r1-1, v1-1-3; metatarsus d1-1- 2, p0-1-1, v10(9); tarsus p2 v2.

Scopula : dense, absent on metatarsus I-II and tarsi III-IV; entire on palpal tarsus and tarsi I and II. Palpal claw with 2 probasal tiny teeth. Paired claws on tarsi I-II with one tooth on inner and 4-5 teeth on outer margin; on tarsi III - with basal outer cluster of 3 teeth, on tarsus IV - with same cluster of 2 teeth, unpaired claw moderately small and steeply curved. Trichobothria: 2 rows of 8-9 per row on tibiae, 12-15 on metatarsi, 12-13 on tarsi, 15 on palpal tarsus.

Spermathecae as in figures 12c,d; apical half strongly bent (almost to right angle); height and width in the base almost subequal, stems separated by basal width of spermatheca, heads separated by about 1.5 basal width.

Spinnerets ( Figure 4e). PMS: length 1.08; diameter 0.51. PLS: maximum diameter 1.09; length of basal, medial and apical segments 1.60, 0.96, 0.95; total length 3.51; apical segment short-digitiform.

Distribution: The new species is known only from Sumatra.