Philotella subiasi, Gao & Palacios-Vargas & Arango & Bu, 2024

Gao, Yan, Palacios-Vargas, José G., Arango, Angela & Bu, Yun, 2024, First records of Micranurida and Philotella (Collembola, Neanuridae, Pseudachorutinae) from China with the description of three new species, Zootaxa 5555 (1), pp. 116-124 : 123

Philotella subiasi sp. nov., Palacios-Vargas, Bu & Gao

Figures 20–28 .

Material examined. Holotype: female (slide No. HB-C2016030) ( SNHM), North China, Hebei Province, Pingquan, Liaoheyuan , 41°19.21’ N 118°26.42’ E, 1230 m alt., soil samples from mixed forest, 13-VII-2016, collected by Yun Bu. Paratypes: 1 female (slide No. HB-C2016033), same data as holotype ; 1 female (slide No. HB-C2016013), North China, Hebei Province, Chengde, Mulanweichang , 41°54.62’ N 116°51.05’ E, 1458 m alt., soil samples from mixed forest, 11-VII-2016, collected by Yun Bu. All specimens are deposited in Shanghai Natural History Museum ( SNHM) .

Diagnosis. Tiny, unpigmented species with short body setae; ocelli absent; five subcylindrical antennal sensilla on Ant. IV; PAO with 9–10 vesicles; the presence of only two prelabral setae; almost complete dorsal chaetotaxy with seta p2 present on all terga from Th. II to Abd. IV; Th. I with 3+3 setae; thickened sensilla present on Th. II and Abd. IV.

Description. Body shape short and broad, with short dorsal setae ( Fig. 20 ), length 0.40–0.42 mm, holotype 0.40 mm. White in ethanol. Tegument granulation uniform.

Antennae slightly shorter than head, Ant. III–IV fused dorsally. Ant. IV with simple apical vesicle, external ms, subapical or, seta i, five banana-like sensilla present and one short and thine sensillum ( Fig. 21 ). Antennal organ of Ant. III typical, inner sensilla small, both sgv and sgd curved, sgv longer, ventral ms present ( Fig. 22 ). Ant. I–II with 6–7 and 11 setae, respectively.

Head without ocelli ( Fig. 20 ). PAO rounded, consisting of 9–10 round vesicles ( Fig. 20 ); Buccal cone relatively long. Mandible delicate, with three apical teeth ( Fig. 25 ). Maxilla styliform, with two hooks ( Fig. 26 ). Labrum with 0/2, 5, 2 setae ( Fig. 24 ). Labium with 11 setae and two sensorial elements on each side ( Fig. 23 ). Head ventrally with 2+2 postlabial setae ( Fig. 23 ).

Dorsal chaetotaxy symmetrical ( Fig. 20 ). Ordinary setae short and acuminate, lateral sensilla on Th. II and dorsal one on Abd. IV clearly thickened, banana-like; other dorsal sensilla slender, thin and longer than ordinary setae, total number of tergal sensilla as: 22/11111; lateral ms present only on Th. II. Head with unpaired seta d0 and 4 setae on ocular field ( Fig. 20 ). Th. I with 3+3 setae ( Fig. 20 ). Terga from Th. II to Abd IV with setae p2 present ( Fig. 20 ). Abd. V with 2+2 axial setae ( Fig. 20 ).

Thoracic sterna without setae. Ventral tube with 4+4 setae ( Fig. 27 ). Sternum of Abd. II without unpaired axial seta, sternum of Abd. III with one pair of middle setae ( Fig. 27 ). Abd. IV with 8–9 ventral setae on each side, without furcal remnant ( Fig. 27 ). Anal valves each with 11 normal setae and 3 hr tiny microsetae ( Fig. 27 ).

Legs I–III with 1, 2, 2 setae on subcoxae, 3, 6, 6–7 setae on coxae, 6, 6, 5–6 setae on trochanters, and 12, 12, 10–12 setae on femora. Tibiotarsi with 19-19-18 setae ( Fig. 28 ). Unguis toothless, unguiculus absent.

Etymology. The species is named after the late Dr. Luis S. Subías Esteban, Spanish acarologist, for his important contribution to the soil mites.

Remarks. Philotella subiasi sp. nov. is similar to P. glabrasterna sp. nov. and P. caeca because they lack eyes, they share the same head chaetotaxy. Di areas of Th. II and III have 3 setae in all these species, whereas abdominal areas Di in P. subiasi sp. nov. and P. caeca have 3 setae and in P. glabasterna sp. nov. only 2 setae. Abd. V of P. subiasi sp. nov. has two rows of setae while P. glabrasterna sp. nov. and P. caeca have only one row. Ventral chaetotaxy in both Chinese species is much different, Abd. II and IV have 2 + 2 and 8 + 8 microseta in P. glabrasterna sp. nov. and 4 + 4 and 9 + 9 such setae in P. subiasi sp. nov.

Figures

FIGURES 20–28. Philotella subiasi sp. nov. 20, dorsal body chaetotaxy; 21. Antenna, dorsal view; 22, Ant. III and IV, ventral view; 23, labium chaetotaxy and postlabial setae; 24, labrum chaetotaxy; 25, Mandible; 26, Maxilla; 27, Abd. I–VI of a female, ventral view; 28, Leg III.