New species of Crossodonthina from Mangshan National Nature Reserve (Nanling National Forest Park), China (Collembola: Neanuridae) Author Jiang, Ji-Gang 0000-0002-4484-3312 College of Life and Environmental Science, Hunan University of Arts and Science. Changde 415000, Hunan, China. & College of Life Science and Technology, Central South University of Forestry and Technology, Changsha 410004, Hunan, China. Corresponding author. jjgangnanjing @ 163. com; https: // orcid. org / 0000 - 0002 - 4484 - 3312 Author Wang, Qing-Yun College of Arts, Hunan University of Arts and Science. Changde 415000, Hunan, China. text Zootaxa 2021 2021-11-25 5071 4 587 599 journal article 3298 10.11646/zootaxa.5071.4.7 07103a61-bc26-4fcc-8d1f-4e8bdcc5dbfa 1175-5326 5726552 EA11BDAF-C8EA-4699-9F9D-8FED3CF0B66A Crossodonthina acuminata sp. nov. Figures 2 , 11–17 , Tables 4–6 Type material. Holotype : Female , China , Hunan , Yizhang County , Mangshan National Nature Reserve . Coordinates: 24.967959N , 112.957361E , alt. 1070m , on the highway side at Tiantaishan, in forest of bamboo, leg. Ji- Gang Jiang, Yu-Yao Zhao, Fang-Jun Chen, 8.iv.2018 (J2018040806) . Paratypes : 4 females , Hunan , Yizhang County , on the road sides near the waterfall at Jiangjunzhai, leg. Ji-Gang Jiang , Yu-Yao Zhao , Fang-Jun Chen , 7.iv.2018 (J2018040711) ( 24.954720N , 112.923782E , alt. 1121m ) ; one female , ibid, Mangshan National Nature Reserve , near the entrance of Jiangjunzhai , in decayed leaves, leg. Ji-Gang Jiang , Yu-Yao Zhao , Fang-Jun Chen , 6.iv.2018 (J2018040602) ( 24.956291N , 112.955372E , alt. 1230m ) ; one female , ibid, Mangshan National Nature Reserve , in a pit on the sides of highway near the hydropower station, in decayed leaves, leg. Ji-Gang Jiang , Yu-Yao Zhao , Fang- Jun Chen , 7.iv.2018 (J2018040704) ( 24.977702N , 112.939269E , alt. 930m ) . Type materials are housed in the Key Laboratory of Zoology , Hunan University of Arts and Science ( HUAS ), Changde , Hunan Province , China . Etymology. The name of the species derives from its acuminate body macrochaetae. Diagnosis. Three black eyes per side on head; all cephalic tubercles independent; chaeta O on tubercle Fr present; cephalic tubercle Di, De on posterior area of head with 2 chaetae each, arranged as intermediate between cross and non-cross type ; mandible with 3 teeth and 8 rami; tubercle De of Th. I with 3 chaetae; furcular remnant without any chaeta. Description. Body length: holotype , female, 2.6mm ; paratypes , females, 2.6–3.8mm . Body color: red while living and white in alcohol ( Fig. 2 ). Chaetal morphology. Body dorsal side with four types of ordinary chaetae: long macrochaetae (Ml), short macrochaetae (Mc), very short macrochaetae (Mcc) and mesochaetae (me). All chaetae thin, smooth and pointed. S-chaetae (s) on terga smooth, thinner than ordinary chaetae, and equal to Ml in length. Head (Table 4, Fig. 11 ). Eyes 3+3, black. Antenna 4-segmented. Ant. I with 10 chaetae. Ant. II with 11 chaetae. Two guard chaetae sgd and sgv present dorsally and ventrally on Ant. III respectively. Two short rods exposed in separate pits. Dorsally, 8 subequal, thickened and curved sensilla present on Ant. IV, apical bulb trilobed, organite (or) present ( Fig. 14 ). Ventral chaetotaxy of Ant. IV: ap with 7 bs and 2 miA, ca with 2 bs and 1 miA, cm with 4 bs and without miA, and cp with 7 miA ( Fig. 15 ). On ventral side of Ant. III, Vi, Vc, Ve respectively with 2, 4, 3 chaetae ( Fig. 15 ). TABLE 4. Cephalic tubercles and chaetotaxy of C. acuminata sp. nov .

Tubercle	Number and type of chaetae
Cl	2 Ml
2 Mc (orme)
An	1 Ml
1 Mc
2 me
Fr	2 Mc 1 me
Oc	1 Ml 2 me
Di	1 Ml
1me
De	1 Ml
1 me
Dl	1 Ml+3 me
L	1 Ml+1 me
So	1 Ml+7 me

Buccal cone developed, labrum truncated, labrum chaetae formula as 0/2, 2. Mandible with three basal teeth, five long rami and three short rami ( Fig. 16 ). Maxilla with three lamellae, the longest lamella bifurcated, with filaments on the edge of the big ramus; the middle lamella with two teeth; the shortest lamella with only one pointed tooth ( Fig. 17 ). Labium with 11 chaetae and no papillae x. Dorsal chaetotaxy of head as in Table 4 and Fig. 11 . Tubercles Cl, An, Fr and Oc on dorsal central area independent from each other. Dorsal posterior area with 4 separate tubercles: 2 Di and 2 De, its chaetotaxy arranged as intermediate between cross and non-cross type ( Deharveng 1983 ). Dorsal lateral area with 3 separated tubercles: Dl, L and So, each tubercle L with 2 chaetae. Ventral chaetotaxy of head. Group Vi with 6 chaetae, groups Vea, Vem and Vep with 4, 4 and 3 chaetae respectively. Thorax ( Table 5 & Fig. 12 ). Th. I with 3+3 tubercles: Di with 1 chaeta, De with 3 (or 2) chaetae, Dl with 2 chaetae. Th. II and Th. III respectively with 4+4 tubercles. Tubercle Dl of Th. II with 5 chaetae (including the microsensilla). Chaetotaxy of thorax and legs as in Table 5 . Unguis with a basal inner tooth, unguiculus absent. Chaeta M present on tibiotarsus. TABLE 5. Postcephalic tubercles and chaetotaxy of C. acuminata sp. nov.

Terga	Legs
Di	De	Dl	L	Scx2 Cx	Tr	Fe	T
Th. I	Mc	Ml+2(1)me	Ml+me	–	0 3	6	13	19
Th. II	Ml+Mc+me	Ml+4me+s	Ml+2me+s+ms	Ml+3me	2 7	6	12	19
Th. III	Ml+Mc+me	Ml+3me+s	Ml+2me+s	Ml+2me	2 8	6	11	18
Terga	Sterna
Abd. I	Ml+Mc+me	Ml+2me+s	Ml+me	Ml+3-5me+s	VT: 4
Abd. II	Ml+Mc+me	Ml+2me+s	Ml+me	Ml+4-6me+s	Ve: 4 (Vel present)
Abd. III	Ml+Mc+me	Ml+2me+s	Ml+me	Ml+6-7me+s	Ve:4-5, Fu: 0, 0 mi
Abd. IV	Ml+me	Mc+me+s	Ml+Mc+me	2Ml+5-6me	Vei:2, Vec:3(4), Vel:4, Vl:6–8
Abd. V	1Mc+2me	s	Ml+2me+1mi	2Ml+2(1)me	Ag:3, Vl: 3
Abd. VI	-------------- 2Ml+1Mc+4me --------------			Ve: 16, An: 3 mi

Abdomen ( Table 5 & Fig. 12 ). Abd. I–IV respectively with 4+4 tubercles, tubercle L of Abd. I with 5–7 chaetae (4–6+s), tubercle L of Abd. II with 6–8 chaetae (5–7+s), tubercle L of Abd. III with 8–9 chaetae (7–8+s), tubercle L of Abd. IV with 8 chaetae, without sensory chaeta. Abd. V dorsally with 3+3 tubercles, two tubercles Di separate from each other, tubercle De separate from Dl, tubercle L with 3–4 chaetae. Abd. VI with 1 tubercle on each side. Ventral tube with 4+4 chaetae ( Fig. 13 ). Furcular remnant without chaeta. Ecology. The new species was found only in the litter of studied forests. FIGURES 11–13 . C. acuminata sp. nov. 11 Head dorsal tubercles and chaetotaxy, 12 Body dorsal tubercles and chaetotaxy (left side), 13 Ventral side of Abd. I – VI. Remarks. The new species can be differentiated from all known species of genus Crossodonthina by the following character combination: all cephalic tubercles independent, cephalic tubercle Di, De with 2 chaetae each, arranged as intermediate between cross and non-cross type chaetotaxy on posterior area of head, mandible with 3 teeth, five long rami and three short rami. Maxilla with 3 lamellae. Tubercle De and Dl of Th. I with 3(2) and 2 chaetae respectively, furcular remnant without chaeta, tubercle L of Abd. I–III with a sensory chaeta each. Crossodonthina acuminata sp. nov. is the eleventh species with 3+3 eyes in the genus Crossodonthina . The new species is similar to C. formosana Yosii, 1965 from Taiwan in macrochaetae on terga smooth and pointed, tubercle Di on Th. II–Abd. III present, maxilla with 3 lamellae, Ant. IV with trilobed apical bulb, ventral tube with 4+4 chaetae. However, the former can be differentiated from the latter by having separated tubercle Dl, L and So on head, 8 rami and 3 teeth on mandible, 3 (2) chaetae on tubercle De of Th. I and no chaeta on Fu, versus having fused tubercle Dl+L+So on head, 4 rami and 1 big tooth on mandible, 1 chaeta on tubercle De of Th. I and 3 chaetae on Fu. FIGURES 14–17 . C. acuminata sp. nov. 14 Ant. I – IV, dorsal view, 15 Ant. III – IV, ventral view, 16 mandible, 17 maxilla. C. acuminata sp. nov. also resembles C. nipponica Yosii, 1954 from Japan by the following characters: macrochaetae on terga smooth and pointed, cephalic tubercles Dl, L and So independent, mandible with 3 basal teeth and claw with an inner tooth. However, the former can be differentiated from the latter by having well defined tubercle Di on Th. II–Abd. IV, 8 rami on mandible, 2 chaetae on tubercle Dl of Th. I and no chaeta on Fu, versus having obscure tubercle Di on Th. II–Abd. IV, 2 rami on mandible, 1 chaeta on tubercle Dl of Th. I and 3 chaetae on Fu. In the genus Crossodonthina , C. altamontana Yoshii, 1981 has no chaetae on Fu, that is similar to C. acuminata sp. nov. However, the new species can be differentiated from the former by having 3 chaetae on tubercle Oc, separated tubercle Dl, L and So on cephalic lateral area, chaeta O present on tubercle Fr, versus 2 chaetae on tubercle Oc, fused tubercle Dl, L and So on cephalic lateral area, chaeta O absent on tubercle Fr. Furthermore, C. clavata sp. nov. and C. acuminata sp. nov. can be discriminated from each other and From known species with 3 eyes by the key provided below.