Micranurida hunanensis, 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 : 118

Micranurida hunanensis sp. nov., Gao, Bu & Palacios-Vargas

Figures 1–9

Material examined. Holotype: female (slide No. HN-MS-2020234) ( SNHM), South China, Hunan Province, Chenzhou, Yizhang , Mangshan , 24°59.56' N 112°54.92' E, 821 m alt., soil samples from mixed forest, 25-VIII-2020, collected by Cheng-Wang Huang. Paratypes: 4 females (slide Nos. HN-MS-2020233, HN-MS-2020234), same data as holotype ; 2 females (slide No. HN-MS-2020235), South China, Hunan Province, Chenzhou, Yizhang , Mangshan , 24°55.26' N 112°58.72' E, 1628 m alt., soil samples from bamboo forest, 26-VIII-2020, collected by Cheng-Wang Huang ; 2 females (slide No. HN-NS-2020239), South China, Hunan Province, Shaoyang, Chengbu , Nanshan , 26°18.48' N 110°29.56' E, 1313 m alt., soil samples from bamboo forest, 8-IX-2020, collected by Cheng-Wang Huang. All specimens are deposited in Shanghai Natural History Museum ( SNHM) .

Diagnosis. Tiny, white species characterized by the presence of 2 + 2 relatively dark ocelli; five spherical antennal sensilla on Ant. IV; PAO with 6 vesicles; dorsal chaetotaxy with p2 present on terga Th. II and Th. III but absent on Abd. I to Abd. V; thickened cylindrical lateral sensilla on Th. II and dorsal ones on Abd. IV; legs with 17–17–16 tibiotarsl setae.

Description. Body length 0.30–0.42 mm, holotype 0.38 mm, slender and elongated ( Fig. 1 ). Body white in ethanol. Tegumental granulation fine and uniform, slightly tuberculated on dorsal side.

Antennae slightly shorter than head, Ant. III–IV fused dorsally. Ant. IV with simple apical vesicle; external ms, subapical or, seta i and five spherical sensilla present ( Figs 2–3 ).Ant. organ Ant. III typical, inner sensilla small, both sgv and sgd curved, sgv extremely long and curved, ventral m’ present. Ant. I–II with 7 and 11 setae, respectively.

Head with 2 + 2 relatively dark ocelli, clearly visible on ocular fields among surrounding secondary granules ( Fig. 1 ). PAO rounded or slightly elliptic, with 6 vesicles ( Fig. 1 ); ratio of its longer axis to nearby ocellus as 2.2–2.5:1. Buccal cone not especially long. Maxilla styliform, with two lamellae, with inner one hook-shaped ( Fig. 4 ). Mandible delicate, with three apical teeth ( Fig. 5 ). Labrum with 4/3, 4, 2 setae ( Fig. 6 ). Labium with 11 pairs of setae ( Fig. 7 ). Head ventrally with 2 + 2 postlabial setae ( Fig.7 ).

Dorsal chaetotaxy symmetrical ( Fig. 1 ). Ordinary setae thin and acuminate, lateral sensilla on Th. II and dorsal ones on Abd. IV clearly thickened; other dorsal sensilla slender, thin and longer than ordinary setae, total number of tergal sensilla as usual: 22/11111; lateral ms present only on Th. II. Head with unpaired seta d0 and 3 setae on ocular field ( Fig. 1 ). Th. I with 2+2 setae. Terga of Th. II and Th. III with setae p2 present and set anteriorly to other setae of p-row. Setae p2 absent from Abd. I to Abd V. Abd. V with 2+2 axial setae ( Fig. 1 ).

Thoracic sterna without setae. Ventral tube with 4+4 setae ( Fig. 8 ). Unpaired axial seta present on sternum of Abd. II and Abd. III ( Fig. 8 ). Furcal remnant without distinct cuticular swelling with 1+1 larger setae and few tiny setae (4–6) ( Fig. 8 ). Anal valves with 13+13 normal setae ( Fig. 8 ).

Legs I–III with 1, 2, 2 setae on subcoxae, 7, 7, 7 setae on coxae, 7, 7, 7 on trochanters, and 11–12, 12, 12 setae on femora. Tibiotarsi with 17–17–16 setae, setae T1 and M absent on all legs, seta B7 also absent on leg III ( Fig. 9 ). Unguis toothless, unguiculus absent.

Etymology. The species is named after Hunan Province where the type specimens were collected.

Remarks. Micranurida hunanensis sp. nov. is similar to M. pygmaea in the shape of PAO and antennal sensilla, both having 2+2 ocelli on head and 2+2 setae on Th. I. They can be easily distinguished because the shape of tergal sensilla (lateral sensilla on lateral Th. II and dorsal ones on side Abd. IV distinctly thickened in M. hunanensis sp. nov. vs slender in M. pygmaea ), and the chaetotaxy on tibiotarsi (17–17–16 setae in M. hunanensis sp. nov., vs 18–18– 17 in M. pygmaea ).

Figures

FIGURES 1–9. Micranurida hunanensis sp. nov. 1, dorsal body chaetotaxy; 2, Ant. III and IV, ventral view; 3. Ant. III and IV, dorsal view; 4, Maxilla, two positions; 5, Mandible; 6, labrum chaetotaxy; 7, labium chaetotaxy and postlabial setae; 8, Abd. I–VI of a female, ventral view; 9, tibiotarsus 1.