Thalassaphorura xihuensis Sun & Li, 2015, sp. nov.
Creators: name: Sun, Xin
name: Li, Yu
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Entognatha
Collembola
Onychiuridae
Thalassaphorura
Thalassaphorura xihuensis

description: Thalassaphorura xihuensis sp. nov.
Figs 12–24
Type material. Holotype female, China, Zhejiang Province, Hangzhou City, Xihu Park (30˚15’44” N, 120˚08’41” E), 0 6 December 2014, litter and soil in the broadleaved forest, Berlese extraction, Sun Xin leg. Paratypes 11 females and 3 males, same data as holotype.
Description. Body white in alcohol. Length of body 0.80–1.05 mm in females, 0.72–0.75 mm in males; holotype 0.9 mm. Shape of body: cylindrical with anal spines on papillae. Anal spines 0.7 times as long as inner edge of hind unguis.
Pso formulae 32/233/33343 dorsally and 11/000/01120 ventrally (Figs 12, 18, 22). Subcoxae 1 of legs I–III with 2 pso each. Psx formulae 00/000/110000 ventrally (Figs 12, 18, 22). Subcoxae 1 of legs I–III without psx. Psp formulae 00/011/ 111100 dorsally and 00/111/0001m0 0 ventrally (Figs 12, 18, 22).
Head. Antennae as long as head. Length ratio of Ant. I: II: III: IV as about 1: 1.5: 1.5: 2.0 (Fig. 15). Subapical organite on Ant. IV with globular apex; basolateral ms at about 1/4 length from the base, above the first proximal row of chaetae (Fig. 15). Ant. III sensory organ consists of 4 papillae, 5 guard chaetae, 2 small rods, and 2 smooth sensory clubs; lateral ms just behind sensory organ (Figs 14, 15). Ant. II with 13 chaetae. Ant. I with 8 chaetae. Antennal base not clearly marked. PAO with 20–24 simple vesicles arranged in two rows along axis of organ (Fig. 17). Dorsal cephalic chaeta d0 present. On head 3+3 medial p-chaetae present between posterior pso, p1 and p3 anterior to p2 (Fig. 21). Mandible with strong molar plate and 4 apical teeth. Maxilla bearing 3 teeth and 6 lamellae. Maxillary palp simple with 1 basal chaeta, with 2 sublobal hairs. Labral chaetae 4/142. Labium with 6 proximal, 4 basomedian (E, F, G, and f) and 6 basolateral (a, b, c, d, e, e’) chaetae (Fig. 13); labial type AC, papillae A–E with 1, 4, 0, 3 and 2 guard chaetae respectively (Fig. 13). Postlabial chaetae 4+4 along ventral groove (Fig. 22).
Body chaetotaxy. S-chaetae well differentiated, formulae as 11/011/222120 dorsally, 11/000/000100 ventrally (Figs 12, 22). Tiny and blunt ms present on both Th. II and III (Figs 12, 19). Th. I tergum with 6+6 chaetae. Th. II–Abd. III terga with 3+3 chaetae along axial line, without unpaired axial chaetae (Fig. 12). Abd. IV tergum with one axial chaeta m0, Abd. V tergum often with one axial chaeta a0, Abd. VI tergum with two axial chaetae a0 & m0 (Figs 12, 20). Th. I–III sterna with 1+1, 1+1, 1+1 chaetae respectively.
Appendages. Subcoxae 1 of legs I–III with 4 chaetae each, subcoxae 2 with 1, 4 and 4 chaetae respectively. All tibiotarsi with 18 (1, 8, 9) chaetae (Fig. 16). Unguis without teeth. Unguiculus 0.7 times as long as inner edge of unguis, without inner basal lamella (Fig. 16). Ventral tube with 1+1 anterior chaetae, 6+6 distal chaetae and 2+2 basal chaetae. Furca reduced to finely granulated area, with 4 small dental chaetae arranged in two rows posteriorly and one manubrial row of chaetae (Figs 18, 23).
Genital plate with 12–15 chaetae in females, 28–30 in males. Male ventral organ absent. Anal valves with numerous acuminate chaetae; each lateral valve with chaetae a0, 2a1 and 2a2; upper valve with chaetae a0, 2b1, 2b2, c0, 2c1 and 2c2 (Fig. 24).
Ecology. In broadleaved litter and soil, in an urban recreational park.
Derivatio nominis. Named after the type locality.
Discussion. T. xihuensis sp. nov. belongs to the small group of congeners characterized by the presence of only 4 papillae in AIIIO. Up to now, four such species are known: T. butrosi (Christiansen, 1956), T. franzi (Stach, 1946), T. cryptopyga (Denis, 1931), and T. tovtrensis (Kaprus’ & Weiner, 1994). T. xihuensis sp. nov. can be separated from T. butrosi and T. franzi by the dorsal pso formula (32/233/ 33343 in the new species, 32/122/ 22(1)3(2)3(2)2 T. butrosi). T. xihuensis sp. nov. differs from T. cryptopyga by the ventral pso formula (11/000/ 0 1120 in the new species, 11/000/01000 in T. cryptopyga), anterior chaetae on the ventral tube (1+ 1 in the new species, absent in T. cryptopyga), and the presence of AS (absent in T. cryptopyga). T. tovtrensis is most similar to the new species having the same pso formulae (32/233/33343 dorsally and 11/000/01120 ventrally), 2 pso on subcoxae 1 of all legs, 1+1 chaetae on each thoracic sternum, ventral tube with 1+1/6+6/2+2 chaetae and 9 distal chaetae on tibiotarsi. Nevertheless the new species can be easily distinguished due to longer AS (two spiniformed chaetae present in T. tovtrensis instead of true AS, more vesicles in PAO (20–24 versus 10–13 in T. tovtrensis), and 5 guard chaetae in AIIIO (versus 4 in T. tovtrensis).
description: Published as part of Sun, Xin & Li, Yu, 2015, New Chinese species of the genus Thalassaphorura Bagnall, 1949 (Collembola: Onychiuridae), pp. 261-271 in Zootaxa 3931 (2) on pages 265-268, DOI: 10.11646/zootaxa.3931.2.5, http://zenodo.org/record/239478