Thalassaphorura brevisetosa Sun & Gao & Potapov 2013, sp. nov.
Creators: name: Sun, Xin
name: Gao, Yan
name: Potapov, Mikhail B.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Entognatha
Collembola
Onychiuridae
Thalassaphorura
Thalassaphorura brevisetosa

description: Thalassaphorura brevisetosa sp. nov.
(Figures 1 and 2)
Type material
Holotype: male, Yangma Island, 37°27 ′ N, 121°36 ′ E, sandy beach (No. 81), 22 April 2011. Paratypes: 11 females and 9 males, same as holotype; 19 females, 37°27 ′ N, 121°30 ′ E, sandy beach (No. 94–101), 23 April 2011. All from Shandong Province, northeast China, leg. M.B. Potapov, Y.X. Luan and C.W. Huang. Holotype and 20 paratypes (16 females and 4 males) are deposited in SIPPE, 9 paratypes (8 female and 1 male) in MSPU, and 10 paratypes (6 females and 4 males) in NEIGAE.
Description
Body white in alcohol. Size 750–870 µm in females, 650–800 µm in males; holotype: 750 µm. Body subcylindrical, body sides almost parallel.
Pseudocellar formula: 32/133/33343 dorsally, 11/000/00010 ventrally (Figures 1A, B, 2A, E), subcoxa 1 of legs I–III with 1, 1 and 1 pso, respectively. Parapseudocelli absent. Pseudopore formula: 00/011/11110 dorsally, 00/111/000x0 ventrally.
S-chaetae subcylindrical, well differentiated, formula: 11/011/221121 dorsally, 11/000/000100 ventrally (Figures 1A,B, 2A, E). Sp present on dorsal side of head. Tiny and blunt ms, present on Th. II–III.
Head. Antennae short and distinctly segmented, as long as head or slightly longer. Length ratio of Ant. I: II: III: IV as about 1: 1.8: 1.8: 2. Ant. IV with subapical organite with apex globular; basolateral ms at about one-third length from base. Ant. III sensory organ composed of five papillae, five guard chaetae, two small sensory rods and two smooth subequal clubs, and a lateral ms (Figure 1C, F). Ant. II with 12 chaetae. Ant. I with eight chaetae. Antennal base without distinct granulation. PAO composed 16–20 simple vesicles. Dorsal cephalic chaeta d0 present, 3 + 3 p-chaetae present between two inner posterior pso, p1 anterior to others (Figure 1A). Mandible with strong molar plate and four apical teeth. Maxilla bearing three teeth and six lamellae (Figure 2C). Maxillary outer lobe with a simple palp, one basal chaeta and two sublobal hairs. Labral chaetae formula 4/142. Labium with six proximal, four basomedian (E, F, G, F) and five basolateral (b, c, d, e, e’) chaetae; labial type A, papillae A–E respectively with 1, 4, 0, 3 and 2 guard chaetae (Figure 1D). Postlabial chaetae 3 + 3 along ventral groove (Figure 2A).
Body chaetotaxy (Figures 1A, B, and 2F). Ordinary chaetae short, weakly differentiated to mesochaetae and macrochaetae, ratio sp: m1: p1 on Abd. V tergum = 1: 0.6: 1.2. Th. I tergum with 5 + 5 dorsal chaetae. Th. II–III terga with 4 + 4 chaetae and Abd. I–III terga with 3 + 3 chaetae respectively on both sides of axial line, sometimes with asymmetric chaetae. Abd. IV tergum with asymmetric chaetae, Abd. V tergum without axial chaetae, Abd. VI tergum with one axial chaeta (a0) (Figure 1 B). Th. I, II and III sterna each with 1 + 1 chaetae.
Appendages. Subcoxa 1 of legs I–III with 3, 3 and 3(4) chaetae, subcoxa 2 with 1, 3 and 3 chaetae respectively (Figure 2E). Tibiotarsi of legs I, II and III with 18 (1, 8, 9) chaetae each. Unguis without teeth. Unguiculus reduced to small blunt process (Figure 1E). Pretarsus armed with transversal circular ridge with two pairs of warts anterior and lateral (Figures 1E and 2D). Ventral tube with 10 + 10 chaetae: 1 + 1 anterior, 7 + 7 distal chaetae, and 2 + 2 basal chaetae. Furca reduced to a field of fine granulation and with four small dental chaetae arranged in two rows below; with only one manubrial row of chaetae (Figure 2F).
Genital plate with 8–10 chaetae in females, 24–26 chaetae in males. Male organ absent. Anal valves with numerous acuminate chaetae; each lateral valve with a0 and 2a1; upper valves with chaetae a0, 2b1, 2b2, c0, 2c1, 2c2 (Figure 2B). Anal spines set on indistinct papillae, 0.7 times as long as inner edge of hind unguis.
Ecology
Highly abundant in one sample in sand dunes.
Etymology
Named after the short chaetae on the body.
Remarks
The new species is peculiar in its wart-like blunt unguiculus, which was not previously found in the genus. Otherwise, T. brevisetosa sp. nov. resembles two seaside European species namely T. debilis and T. thalassophila. The latter is considered to be a synonym of the former (Fjellberg 1998), however, the relationships between these two species and all other forms of T. debilis remain unresolved (Sun et al. 2010). Thalassaphorura brevisetosa sp. nov. and T. debilis / thalassophila share pso formula 32/133/33343, 1/1/1 pso on subcoxae, 1 + 1/1 + 1/1 + 1 ventral chaetae on Th. I–III, 1 + 1/7 + 7/2 + 2 chaetae on ventral tube, and middle-sized anal spines (ratio of AS / hind unguis about 0.7). The new species differs by body being half the size, the presence of a pair of ventral pso on the abdomen, almost totally reduced unguiculus and shorter chaetae on the body.
description: Published as part of Sun, Xin, Gao, Yan & Potapov, Mikhail B., 2013, Review of Chinese littoral Thalassaphorura (Collembola: Onychiuridae), with the description of two new species, pp. 575-589 in Journal of Natural History 48 (9 - 10) on pages 576-579, DOI: 10.1080/00222933.2013.839843, http://zenodo.org/record/4631587