Atmetochilus Simon, 1887

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 : 2-3

Atmetochilus Simon, 1887

Simon 1887: 109, type species Atmetochilus fossor Simon, 1887 , by monotypy; 1892: 109; Raven, 1985: 91.

Diagnosis: Closely related to Damarchus and Spiroctenus by possessing subcentral posterior sternal sigilla, proventral to prolateral mating spur and one S-shaped teeth row on paired tarsal claws in males, all considered apomorphic ( Raven 1985). It differs from these taxa by posterior sternal sigilla more or less confluent (vs. broader spaced) and by distinctly flattened male metatarsus I covered with numerous ventral spinules (vs. unmodified state), and by having ventral ridges on the bulb looking like saw in lateral view.

Description: Medium-sized to large nemesiids with carapace 7-12 mm long. Carapace slightly hirsute. Fovea short U-shaped. Eight eyes, AME or ALE largest, eye tubercle well developed. Chelicerae with rastellum. Maxillae broad rectangular with few to numerous cuspules. Serrula not evident. Labium wider than long with few or without cuspules. Sternal sigillae confluent in central part of sternum. Leg formula 4123. Metatarsal preening combs present on metatarsi III and IV. Tarsi III and IV with or without spines.

Males: maxillary cuspules considerably smaller than in females; intercheliceral tumescence not evident; palpal tibia short, swollen, and aspinose; cymbium short and massive, without spines, tegulum with 1-5 ventral ridges; tibia I long cylindrical with usually two (sometimes one) megaspines on the raised prodistal process; metatarsus I straight to slightly curved, flattened laterally, ventrally covered with dense short spinules.

Females: spermathecae entire, not branched, without distinct heads, upper halves diverging. Four spinnerets: PMS large well-developed, apical segment of PLS triangle to digitiform.

Composition: Six species: A. atriceps Pocock, 1900 (ñ, Myanmar), A. bifidus ( Gravely, 1935) (ò, India), A. fossor Simon, 1887 (ñ, Myanmar), A. koponeni sp. n. (ò ñ, Indonesia), A. lehtineni sp. n. (ò ñ, Indonesia) and A. sumatranus sp. n (ò, Indonesia).

Distribution: Southeastern Asia from Assam ( India) to Sumatra ( Indonesia) as shown in figure 1. The undescribed congeners were also reported by Schwendinger (1996) from Thailand.