Atmetochilus sumatranus, 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 : 12-13

Atmetochilus sumatranus sp. n.

( Figures 2f, 3e, 4f, 5e, 6f,g, 7d, 8d, 9e, 10d, and 11d,e) urn:lsid:zoobank.org:act:088B7C5E-1640-4145-B8D9-ADBD1847F9E8

Types: ò holotype - INDONESIA: Sumatra, Pantai Permai, near sea coast, 3°39'N, 98°58'E, 19.02.1913, O. Zohn - 1ò (ZISP).

Etymology: Named after the distribution area: Sumatra Island.

Diagnosis: Atmetochilus sumatranus sp. n. can be distinguished from A. fossor and A. atriceps by presence of cuspules on the labium (vs. unarmed state) and from A. koponeni sp. n. and A. lehtineni sp. n. - by having two well developed tegular ridges (cf. Figures 8-11). Males of A. sumatranus sp. n. differ from those of two latter species as well as from males of A. bifidus by a narrower prodistal process on tibia I carrying one megaspine (vs. two megaspines in all other male congeners - cf. Figures 6b,e,g and Gravely, 1935: figure 1a).

Description: Male (holotype). Habitus as shown in figure 2f. Body length 19.87. Colour in alcohol: carapace including eye tubercle and chelicerae intensive reddish-orange; eyes circled with blackish markings; labium, sternum, maxillae, palps and legs light to medium yellowish-orange; abdomen and spinnerets light greyish brown, dorsal abdominal pattern uniformly medium brown.

Carapace ( Figure 3e) 7.70 long, 7.13 wide. Eye tubercle and clypeus as shown in figure 4f. Eye sizes and interdistances: AME 0.26 (0.50), ALE 0.47, PLE 0.36, PME: 0.24; AME-AME 0.33 (0.05), ALE-AME 0.24 (0.16), ALE-PLE 0.16, PLE- PME 0.04, PME-PME 0.81. Rastellum weak, composed of 4-5 thick setae in front of fang base. Cheliceral furrow with 7-8 promarginal teeth and 9-12 mesobasal denticles. Labium, sternum and maxillae as shown in Figure 5e. Labium 0.84 long, 1.36 wide, without cuspules. Sternum 4.43 long, 3.65 wide. Maxillae with 11-12 tiny cuspules confined to probasal edge. Palp and leg measurements as shown in Table 5.

Spination: Femora I-III with 1-2 (femur IV with 4-6) basodorsal spines and few stiff bristles (undeveloped spines) located medially and distally; femora III-IV also with few dirsodistal spinules, patellae III-IV with numerous pro- and retrolateral spinules; tibia III dorsally with about 15 stiff bristles; palp entirely, patellae I-II and tarsi I-II aspinose. Leg I: tibia pv0-0-M, rv1-0-0; metatarsus v1-1-3. Tibia and metatarsus I and tibial process carrying megaspines as shown in Figures 6f,g. Leg II: tibia v1-1-2; metatarsus v1-2-1-2-3. Leg III: tibia p1-1, r1-1, v1-1-3; metatarsus p1-1-1-1, r1-1-1, v2- 2-2-1-4(3); tarsus p5, v3. Leg IV: tibia r0-0-1-0, v1-1-3; metatarsus d1(0)-0-1-1, p0-1-1-1-2, r0-1-1, v0-1-1-1-4; tarsus p2 v3(2).

S c o p u l a: relatively dense, distal on metatarsus I; entire on tarsi I and II; vestigial to absent on tarsi III and IV. Paired tarsal claws with 4-5 teeth in S-shaped row, unpaired claw very small and gently curved. Trichobothria: 2 rows of 7-8 per row on tibiae, 9-12 on metatarsi, 9-11 on tarsi, 8 on cymbium.

Palp: cymbium aspinose ( Figure 7d); bulb with protruding carina; tegulum with 2 well developed ridges, ridges form coil in ventral view; embolus curved ( Figures 8d, 9d,e, 10d, 11d,e).

Spinnerets: PMS: 1.01 long; diameter 0.33. PLS: maximum diameter 0.85; length of basal, medial and apical segments 1.72, 0.84, 0.77; total length 3.33; apical segment short-digitiform.

Female unknown.

Distribution: The new species is known only from the type locality.