Ceratophysella gracilimucronata Jia, Zhao & Skarżyński, 2024

Jia, Junli, Zhao, Xuemeng, Skarżyński, Dariusz, Wu, Ruiwen, Cheng, Liping & An, Jianmei, 2024, Morphological description and DNA barcoding of Ceratophysella gracilimucronata sp. nov. (Collembola: Hypogastruridae) from China, with a key to species of the C. armata group of the Sino-Japanese Region, Zootaxa 5432 (4), pp. 555-566 : 556-561

Ceratophysella gracilimucronata Jia, Zhao & Skarżyński sp. nov.

Figs 1–15

Type material. Holotype: female on slide, humus layer in deciduous forest, Nanling Mountain Nature Reserve , Guangdong Province, CHINA (24.9032° E, 113.0479° N, 680 m a.s.l.), 1.viii.2022, leg. Xiping Wei, Jianfeng Jin, Xiuxian Shen, Guoqiang Zhang. Paratypes: 9 females on slides (24.9182° E, 113.0321° N, 490 m a.s.l.; 24.9065° E, 113.0620° N, 550 m a.s.l.; 24.9032° E, 113.0479° N, 680 m a.s.l.), 1.viii.2022. All specimens deposited in the College of life Science , Shanxi Normal University , China .

Description. Body length 0.8–1.2 mm. Body color brown or grey-black in alcohol, ventrally pale. Granulation relatively coarse and uniform, 8–10 granules between macrosetae p 1 on Abd. V ( Figs 8 , 14 ).

Arrangement of setae on head typical of the genus, spine-like setae absent ( Figs 10 , 12 ). Dorsal chaetotaxy of the B type sensu Babenko et al. (1994) ( Figs 9, 11 , 13 , 14 ). Differentiation of dorsal setae into micro- and macrosetae moderately distinct. Setae of medium length, pointed and smooth. Body sensilla (s) long, but shorter than macrosetae. Setae p 1 on Abd. IV developed as macrosetae, p 2 as microsetae, setae a 2 and p 3 present. Microsensilla (ms) on Th. II present ( Figs 11 , 13 ). Subcoxae I, II, III with 1, 2, 3 setae, respectively.

Ant. IV with simple apical vesicle (av), subapical organite (or), microsensillum (ms), 7 (2 lateral, 5 dorsal) cylidrical, subequal sensilla and 12–14 thin, slightly curved and blunt-tipped sensilla in ventral file. Ant. III organ with two long (lateral) and two short (internal), curved sensilla. Microsensillum on Ant. III present. Eversible sac between Ant. III and IV absent. Ant. I with 7 setae ( Figs 1, 2 ).

Eyes 8 + 8. Postantennal organ 1.8–2.2 times as large as single ocellus with four lobes of which the anterior pair larger than the posterior. Accessory boss present ( Figs 3 , 10 , 12 ).

Labrum with 5, 5, 4 setae, 4 prelabrals present ( Fig. 6 ). Head of maxilla of the C. armata type ( Fjellberg 1984: fig. 18). Maxillary outer lobe with 2 sublobal hairs. Labial palp with 5 papillae (A–E) and 6 proximal setae ( Fig.4 ).

Tibiotarsi I, II, III with 19, 19, 18 setae respectively, clavate tenent hairs absent. Claws with inner tooth and two lateral teeth. Empodial appendage with narrow basal lamella and apical filament reaching slightly below inner tooth ( Fig. 5 ). Ventral tube with 4 + 4 setae.

Furca well developed. Ratio dens + mucro/inner edge of claw III = 2–2.7. Dens with uniform granulation and seven dorsal setae (2 inner setae modified). Mucro short (ratio dens/mucro = 2.9–3.8) and slender with small outer lamella ( Figs 7 , 15 ). Retinaculum with 4 + 4 teeth.

Anal spines slightly curved, situated on basal papillae, more or less yellowish ( Fig. 9 ). Ratio: anal spines/claws III = 0.8–1.1.

Etymology. The specific name gracilimucronata comes from the Latin adjective gracilis (slender) and noun mucro (apical part of furca).

Remarks. Having the B type chaeotataxy (sensu Babenko et al. 1994) and short and slender mucro C. gracilimucronata sp. nov. resembles C. ainu ( Yosii, 1972) (Hokkaido, Japan), C. falcifer Cassagnau, 1959 (Pyrenees, France) and C. glancei Hammer, 1953 (Northwest Territories, Canada; Alaska, USA). This new species differs from them by the presence of setae a 2 and p 3 on Abd. IV. Besides, C. ainu can be easily distinguished from C. gracilimucronata sp. nov. by trilobed apical vesicle on Ant. IV (vs. simple), presence of eversible sac between Ant. III and IV (vs. absent) and 20–23 granules between macrosetae p 1 on Abd. V (vs. 8–10 granules) ( Yosii 1972). Also easy to separate are C. falcifer and C. glancei which posses shorter anal spines (ratio: anal spines/claws III: C. falcifer 0.35, C. glancei 0.5–0.66, C. gracilimucronata sp. nov. 0.8–1.1) ( Hammer 1953, Cassagnau 1959, Fjellberg 1985). Moreover, C. flectoseta Lin & Xia, 1983 from Guangdong Province, China seems to be similar to C. gracilimucronata sp. nov., but inaccurate original description ( Lin & Xia 1983) and lost types (letter information from the Institute of Zoology, Guangdong Academy of Sciences) make it impossible to compare them exactly. However, C. flectoseta is easily identified by 7 + 7 ocelli, strongly bent setae on Ant. IV, about 10 setae on dens and claws without inner tooth and lateral teeth. Differences between C. gracilimucronata sp. nov. and other species of the C. armata group (sensu Babenko et al. 1994) recorded from the Sino–Japanese Region are illustrated in the identification key below.

Figures

FIGURE 12. Chaetotaxy of head of C. gracilimucronata sp. nov.

FIGURE 13. Chaetotaxy of Th. I–III of C. gracilimucronata sp. nov.

FIGURE 14. Chaetotaxy of Abd. I–V of C. gracilimucronata sp. nov.

FIGURE 15. Furca of C. gracilimucronata sp. nov.

FIGURES 1–6. C. gracilimucronata sp. nov.: 1, chaetotaxy of Ant. I–IV, dorsal side; 2, chaetotaxy of Ant. III–IV, ventral side; 3, postantennal organ and ocelli; 4, labial palp; 5, claw I with empodial appendage; 6, labrum.

FIGURES 7–11. C. gracilimucronata sp. nov.: 7, furca; 8, chaetotaxy of Abd. V; 9, chaetotaxy of Abd. I–VI; 10, chaetotaxy of head; 11, chaetotaxy of Th. I–III.