Ischnothyreus falcatus, Tong & Li, 2008

Tong, Yanfeng & Li, Shuqiang, 2008, The Oonopid Spiders (Araneae: Oonopidae) From Hainan Island, China, Raffles Bulletin of Zoology 56 (1), pp. 55-66 : 56-59

Ischnothyreus falcatus , new species

( Fig. 2A–K )

Holotype. – Male ( IZCAS), Bawangling National Natural Reserve (19 ° 04'N 109 ° 08'E), Changjiang County, Hainan Island, China, coll. Y. Song, X. Han and Y. Tong, 22 Mar.2005.

Paratypes. – 1 female ( IZCAS), same data as holotype ; 1 male ( IZCAS), Xianren Cave (19 ° 57'N 110 ° 12'E), Shishan Town, Haikou City, Hainan Island, China, coll. Y. Song, X. Han, G. Deng and Y. Tong, 16 Mar.2005 .

Diagnosis. – The male of this new species can be easily recognized by the sickle-shaped process on laterodorsal surface of chelicerae, a similar structure can also be found in I. flagellichelis Xu, 1989 ( Xu, 1989) , but in I. flagellichelis the process is flagelliform, with two segments and a claw on the tip; the female of this new species is characterized by the trapezoid-shaped atrium.

Description. – Male. Body length 1.28; carapace 0.72 length, 0.56 width; abdomen 0.67 length, 0.40 width. Carapace deep orange, chelicerae, sternum, legs, dorsal and ventral scutum light yellow. Carapace with pair of dark-brown, egg-shaped patches behind eyes; with three rows of short hairs. Eyes six in two rows, large, nearly equally sized, compactly arranged; ALE slightly separated; posterior eyes in a straight row, touching each other. Chelicerae with a sickle-shaped process on median of laterodorsal surface, which straight upwards, slowly curved mesially, then abruptly turned outwards; retromargin of fang furrow with a small tooth, promargin with some tiny indistinct teeth; base of cheliceral fang modified. Labium wider than long, endites with pointed tip. Leg I: femur with 2 prolateral and 1 small retrolateral spine, patella spineless, tibia with 4 pairs, metatarsus with 2 pairs of very long ventral spines. Leg II is similar to leg I except femur with only one prolateral spine. Legs III and IV spineless. Measurements of legs: I 1.72 (0.53, 0.21, 0.44, 0.35, 0.19); II 1.70 (0.52, 0.22, 0.41, 0.36, 0.19); III 1.43 (0.44, 0.19, 0.29, 0.33, 0.18); IV 2.12 (0.63, 0.28, 0.48, 0.49, 0.24). Leg formula: 4> 1 = 2> 3. Abdomen with small dorsal scutum, about two-seconds abdominal length. Bulbus of palp elongated, gradually tapering apically, obtusely bent before apex. Embolic part not divided into distinct lobes, bearing some membranous outgrowths.

Female. Similar to male, but chelicerae without sickle-shaped process, base of cheliceral fang unmodified, tip of endites truncated. Body length 1.21; carapace 0.67 length, 0.59 width; abdomen 0.68 length, 0.42 width. Measurements of legs: I 1.80 (0.56, 0.22, 0.48, 0.35, 0.19); II 1.79 (0.53, 0.23, 0.46, 0.38, 0.19); III 1.57 (0.47, 0.22, 0.29, 0.36, 0.23); IV 2.22 (0.63, 0.34, 0.50, 0.51, 0.24). Postepigastric scutum rectangular, with straight posterior margin. A strongly winding tube visible through cuticle, originated from near the middle of epigastric sulcus and running posteriorly into the trapezoid-shaped atrium.

THE RAFFLES BULLETIN OF ZOOLOGY 2008

THE RAFFLES BULLETIN OF ZOOLOGY 2008

Etymology. – Specific name comes from the Latin “ falcatus = sickle-shaped”, and refers to the sickle-shaped process on laterodorsal surface of male chelicerae.

Figures

Fig. 2. Ischnothyreus falcatus, new species: A, male, dorsal view; B, carapace of female, dorsal view; C, carapace of male, lateral view; D, carapace of female, lateral view; E, right male chelicera, frontal view; F, ventral scutum of female, ventral view; G, genital area of female, dorsal view; H, I, J, left male palp in dorsal, prolateral and retrolateral view; K, distal part of male chelicera, posterior view. Scales: A-D = 0.2 mm, E, F, K = 0.1 mm, G-J = 0.05 mm.