Atmetochilus koponeni, 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 : 3-7

Atmetochilus koponeni sp. n.

( Figures 2a,b, 3a,b, 4a,b, 5a,b, 6a,b, 7a, 8a, 9a, 10a, 11a, and 12a,b) urn:lsid:zoobank.org:act:B7A634A7-BD83-4D3A-8FFA-2B0DF4C6D89D

Types: ò holotype (ZMUT) - INDONESIA: Sumatra, Mt. Mamas, 3°33'N, 97°39'E, 1600-1700 m, 28.07- 7.08.1983, H. Räisänen. Paratype: 1ñ (ZISP) - “ Sumatra, 1889” (no other data).

Etymology: Named after our colleague and friend, a famous Finnish arachnologist Seppo Koponen (Turku, Finland).

Diagnosis: The species can be distinguished from A. fossor and A. atriceps by presence of cuspules on the labium (vs. unarmed state) and from A. lehtineni sp. n. and A. sumatranus sp. n. - by the shallow tegular ridges (cf. Figures 8-11). Males of A. koponeni sp. n. differ from those of A. bifidus by less raised tibial process on leg I with confluent megaspines and by shorter, stouter and slightly curved metatarsus I (more raised with diverging megaspines and longer, slender and straight, respectively, in the latter species - cf. Figures 6a,b and Gravely 1935: figure 1a).

Description: Male (holotype). Habitus as in figure 2a. Body length 15.85. Colour in alcohol: carapace and chelicerae dark cherry-brown, labium, sternum, maxillae, palps and legs intensive reddish-brown; abdomen dorsally dark-brown uniformly and densely covered with light brownish spots, ventral abdominal surface and spinnerets pale yellowish grey.

Carapace ( Figure 3a) 6.94 long, 6.11 wide. Eye tubercle and clypeus as shown in figure 4a. Eye sizes and interdistances: AME 0.25 (0.33), ALE 0.37, PLE 0.35, PME: 0.32; AME-AME 0.17 (0.09), ALE-AME 0.19 (0.13), ALE-PLE 0.14, PLE- PME 0.02, PME-PME 0.63. Rastellum consists of 8-9 robust spines. Cheliceral furrow with 9-10 promarginal teeth and 15-17 mesobasal denticles. Labium, sternum and maxillae as shown in Figure 5a. Labium 0.82 long, 1.36 wide, with 2 tiny cuspules. Sternum 3.66 long, 3.24 wide. Maxillae with 15-20 tiny cuspules each. Palp and leg measurements as shown in Table 1.

Spination: Femora I-III with 1-2 (femur IV with 4-5) basodorsal spines and few stiff bristles (undeveloped spines) located medially and distally; femora III-IV also with few dorsodistal spinules, patellae III-IV with numerous pro- and retrolateral spinules; palp entirely, patellae I-II and tarsi I-IV aspinose. Leg I: tibia pv1-1-0, rv0- 0-2M; metatarsus v1-1-3. Tibia and metatarsus I and tibial process carrying megaspines as shown in Figures 6a,b. Leg II: tibia v0-1-2; metatarsus v1-1-3. Leg III: tibia d1-2-2, v0-0-2; metatarsus p0-1-0, r0-1-1, v1-0-2-3(2). Leg IV: tibia v0-0-2; metatarsus d1-1-0, v1-0-1-2-2.

Scopula : relatively short and sparse, distal on metatarsus I, entire on tarsi I and II, absent elsewhere. Paired claws on tarsi I-III with 5-6 teeth in one S-shaped row. Trichobothria: 2 rows of 6-8 per row on tibiae, 10-12 on metatarsi, 10-11 on tarsi, 7 on cymbium.

Palp: cymbium aspinose ( Figure 7a); bulb with low carina; tegulum with one low slanting ridge; embolus curved ( Figures 8a, 9a, 10a, 11a).

PMS: 0.72; diameter 0.34. PLS: maximum diameter 0.57; length of basal, medial and apical segments 1.22, 0.61, 0.87; total length 2.70; apical segment digitiform.

Female (paratype): Habitus as in Figure 2b. Body length 28.50. Colour in alcohol as in male, but carapace coloured only slighter darker than legs, medium chestnut-brown.

Carapace ( Figure 3b) 11.15 long, 8.88 wide. Eye tubercle and clypeus as shown in figure 4b. Eye sizes and interdistances: AME 0.38 (0.50), ALE 0.48, PLE 0.49, PME 0.46; AME-AME 0.23 (0.11), ALE-AME 0.32 (0.26), ALE-PLE 0.23, PLE- PME 0.03, PME-PME 0.92. Rastellum consists of 12-15 robust cone spines. Cheliceral furrow with 8-9 promarginal teeth and 20-25 mesobasal denticles. Labium, sternum and maxillae as shown in Figure 5b. Labium 1.53 long, 2.56 wide, with 3 cuspules. Sternum 6.47 long, 5.64 wide. Maxillae with 22-25 cuspules each. Palp and leg measurements as shown in Table 2.

Spination: Femora I-IV with few dorsal bristles (femora III-IV also with 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 p1-1, v1-2-3; tarsus v2(1). Leg I: tibia v1-1-0; metatarsus v1-1-1-1-2. Leg II: tibia v1-1-0; metatarsus v1-1-2-1-3. Leg III: tibia p1-1, r0-1, v2-2(1)-3; metatarsus d7, p8, r2, v8; tarsus p2, v1. Leg IV: tibia r1-1, v1-2(1)-1-3(2); metatarsus d0-1-1, p0-1-2, v6(5); tarsus p2 v1.

S c o p u l a: dense, distal and entire on metatarsus I-II; entire on palpal tarsus and tarsi I and II; absent on tarsi III-IV. Palpal claw with 4 promarginal tiny teeth. Paired claws on tarsi I-II with 0-1 tooth on inner and 4-5 teeth on outer margin; on tarsi III-IV - with basal outer cluster of 2-3 teeth, unpaired claw steeply curved. Trichobothria: 2 rows of 7-8 per row on tibiae, 10-12 on metatarsi, 11-12 on tarsi, 13 on palpal tarsus.

Spermathecae as in Figures 12a,b, gradually tapering without distinct heads, height about 1.5 longer than width near the base, heads separated by the height of spermatheca; apical half of spermatheca gently bent laterally.

Spinnerets: PMS 1.26 long; diameter 0.51. PLS: maximum diameter 0.98; length of basal, medial and apical segments 1.56, 1.07, 1.15; total length 3.78; apical segment short-digitiform.

Note: Although the holotype male and the paratype female were found preserved in different spider collections, a very similar shape of the eye group, sternal sigillae and spinnerets in both specimens indicates that they belong to the same species.

Distribution: The new species is known only from Sumatra.