Crossodonthina langshanensis, Hu & Jiang & Jiang, 2019

Hu, Ya-Hui, Jiang, Cheng & Jiang, Ji-Gang, 2019, Two new species of Lobellini from Central-South China (Collembola Neanuridae), Zootaxa 4712 (1), pp. 77-89 : 78-82

Crossodonthina langshanensis sp. nov.

Figures 1, 3 , 5 , 7–9 , 15 , 17, 19 , Tables 1–3

Type material. Holotype: female, China, Hunan, Xinning county , Langshan National Geopark. Coordinates: 26.277054N, 110.730618E, alt. 520m, in forest, leg. Ji-Gang Jiang, Cheng Jiang, Li-Ping Duan, 30.iv.2018 (J2018043002) . Paratypes: 2 females, China, Hunan, Xinning county , Langshan National Geopark. Coordinates: 26.276580N, 110.729240E, alt. 470m, in forest, leg. Ji-Gang Jiang, Cheng Jiang, Li-Ping Duan, 30.iv.2018 (J2018043003) ; 3 juvenile, Guangxi, Ziyuan county , Langshan National Geopark , Coordinates : 26.276824N, 110.730528E, alt. 510m, nearby the entrance of the Park, leg. Ji-Gang Jiang, Cheng Jiang, Li-Ping Duan, 29.iv.2018 (J2018042901). Type materials are housed in the Key Laboratory of Zoology, Hunan University of Arts and Science ( HUAS), Changde, Hunan Province, China .

Othermaterial. 2females, China, Hunan, Xinningcounty,LangshanNationalGeopark. Coordinates : 26.276986N, 110.736902E, alt. 527m, in forest, leg. Ji-Gang Jiang, Ya-Hui Hu, Wei Hu, 25.vii.2019 (J2019072502).

Diagnosis. 2+2 black eyes on head; labral chaetotaxy as 2/4, 2; cephalic chaeta O present; tubercle Dl on Th. II with 3 chaetae (2+s); mandible with 2 prominent basal teeth and 2 fringed rami of quite different sizes; maxilla with marginal filaments on outer lamella; tubercle Di on Abd. V separated;

Description. Body length: holotype 2.4 mm, two paratypes 2.3–2.4 mm, three juveniles 1.0– 1.1mm.

Color. Red while living ( Fig. 1 ) and white in alcohol ( Fig. 3 ).

Chaetal morphology ( Fig. 5 ). Dorsal ordinary chaetae of five types: Ml ( Fig. 5 a–b), Mc ( Fig. 5c ), Mcc ( Fig. 5d ), me ( Fig. 5 e–f) and mi ( Fig. 5h ). S-chaetae on terga thin, smooth, shorter than Ml and longer than Mc ( Fig. 5g ).

Head. Eyes 2+2, black. Antenna 4-segmented ( Fig. 15 ). Ant. I with 9 chaetae. Ant. II with 11 chaetae. Ant. III and IV dorsally fused. Dorsal sensory guard chaeta (sgd) on Ant. III not migrated distally, two rods exposed in separate pit. Ant. IV dorsally with 8 slightly thickened and blunt sensilla, apical bulb trilobed. sensory organite (or) present. Ventral chaetotaxy of Ant. IV: ap with 8 bs and 3 miA, ca with 2 bs and 3 miA, cm with 3 bs and 1 miA, cp without miA. On ventral side of Ant. III, Vi, Vc, Ve with 3, 4, 4 chaetae respectively.

Buccal cone moderately developed. Labrum truncated, chaetal formula as 2/4, 2 (adult) or 4/4, 2 (juvenile). Labium with 11 chaetae and 2 x ( Fig. 17 ). Mandible complicated ( Fig. 8 ), consisting of 2 rami, 2 definite teeth and some spine-like chaetae. Small ramus consisting of one spine-like chaeta and 7–8 slender chaetae, large ramus developed, with 2 rows of marginal chaetae, 4 strong and spine-like chaetae, marginal chaetae on ramus simple, bifurcated or tri-furcated, about 9-12 spine-like chaetae present on the central area of basal part of the large ramus. The longer ramus about 10 times as long as the small one. Maxilla consisting of two lamellae, the inner lamella much shorter than the outer one, with two minute apical teeth, the outer one with marginal filaments on inner side ( Fig. 9 ). On ventral side of head, group Vi with 6+6 chaetae, groups Vea, Vem and Vep with 4, 3 and 2 chaetae respectively. Dorsal tubercles and chaetotaxy of head as in Tab. 1 . and Fig. 7 . Dorsal central area with 6 separate tubercles; one tubercle Cl, 2 An, one Fr and 2 Oc, chaeta O absent. Dorsal posterior area with 4 separate tubercles: 2 Di and 2 De. Line of chaetae Di2–De2 crosses line Di1– De1 on head (cross-type, Deharveng 1983). Dorsal lateral area with 1 fused tubercle (Dl+L+So).

Thorax ( Table 2 & Fig. 7 ). Th. I with 3+3 tubercles (Di, De, Dl). Th. II and Th. III with 4+4 tubercles respectively, ms on tubercle Dl of Th. II present (its form as in Fig. 5i ). Chaetotaxy of thorax and legs as in Table 2 . Unguis with a basal inner tooth, unguiculus absent. Chaeta M present on tibiotarsus.

Abdomen ( Table 2 & Fig. 7 ). Abd. I–IV respectively with 4+4 tubercles. Abd. V dorsally with 2+2 tubercles, two tubercles Di close to each other, but not fused together, tubercle De fused to Dl, tubercle L present on ventral side. Abd. VI with 1 tubercle on each side, no cryptopygy. VT with 4+4 chaetae. Furcular remnant with 3-4 chaetae ( Fig. 19 ).

Etymology. The name of the species derives from the locality where it was collected.

Ecology. Among decayed leaves in forest.

Remarks. So far, 12 species of genus Crossodonthina were reported worldwide, 11 species were from Asia and only one from Oceania, seven species were reported from China (Jiang & Zhang, 2012). In genus Crossodonthina , three species have 2+2 eyes, they are C. bidentata , C. hainana and C. montana , the new species is the fourth one with 2+2 eyes. In general appearance, Crossodonthina langshanensis sp. nov. strongly resembles Chinese species C. bidentata ( Luo & Chen, 2009) in the number of mandible basal teeth, the arrangement of body tubercles, the presence of chaeta O of tubercle Fr, the number of chaetae on VT, and the presence of inner tooth on claw. However, these species can be distinguished by the following features: structure of mandible (in C. langshanensis with two fringed rami, in C. bidentata with three fringed rami), structure of maxilla (in C. langshanensis outer lamella fringed, in C. bidentate outer lamella not fringed), whether the tubercle Di fused on Abd. V or not (in C. langshanensis not fused, in C. bidentate fused), the labral chaeta formula (in C. langshanensis 2/4, 2, in C. bidentata 2/5, 2), number of chaetae (besides of ms) on tubercles Dl of Th. II (in C. langshanensis 3, in C. bidentata 4). The new species is also similar to the 2+2-eyed Chinese species C. montana ( Lee & Kim, 1990) and C. hainana ( Xiong et al., 2005) in the arrangement of body tubercles, the presence of chaeta O of tubercle Fr, the separate tubercle Di of Abd. V and the presence of 4+4 chaetae on VT. The new species can be separated from the above species by the characters listed in Table 3 .

Figures

FIGURE 7. Body dorsal tubercles and chaetotaxy of Crossodonthina langshanensis sp. nov.

FIGURES 8–9. Crossodonthina langshanensis sp. nov. 8 mandible, 9 maxilla.

FIGURES 1–4. Body color: 1 body color of Crossodonthina langshanensis sp. nov. while alive. 2 body color of Lobellina gladius sp. nov. when alive. 3 body color of Crossodonthina langshanensis sp. nov. in alcohol. 4 body color of Lobellina gladius sp. nov. in alcohol.

FIGURES 5–6. Chaetae type: 5 chaetae type of Crossodonthina langshanensis sp. nov. a–b: Ml, c: Mc, d: Mcc, e–f: me, g: schaeta, h: mi, i: ms. 6 chaetae type of Lobellina gladius sp. nov. j–l: Ml, m–n: Mc, o: Mcc, p–r: me, s: s-chaeta, t: me.

FIGURES 15–16. Ant. I–IV: 15 Crossodonthina langshanensis sp. nov., 16 Lobellina gladius sp. nov.

FIGURES 17–20. Labium and ventral chaetotaxy of Abd. III–IV: 17 Labium of Crossodonthina langshanensis sp. nov., 18 Labium of Lobellina gladius sp. nov., 19 Crossodonthina langshanensis sp. nov., ventral chaetotaxy of Abd. III–IV, 20 Lobellina gladius sp. nov., ventral chaetotaxy of Abd. III–IV.

Tables

TABLE 1. Cephalic tubercles and chaetotaxy of Crossodonthina langshanensis sp. nov.

Tubercle	Number and type of chaetae	Names of chaetae
Cl	2 Ml 2 Mcc	F G
An	1 Ml 1Mcc 2 me	B E C, D
Fr	2 Ml 1 mcc	A O
Oc	2 Ml 1 mi	Ocm, Ocp Oca
Di	1 Ml	Di1
De	1 Ml	De1
	2 mi	Di2, De2
Dl+L+So	3 Ml+ 7me +2mi or 3Ml+ 8me+1mi	Uncertain

TABLE 2. Postcephalic tubercles and chaetotaxy of Crossodonthina langshanensis sp. nov.

Terga					Legs
Th. I	Di Ml	De Ml+me	Dl Ml	L –	Scx2 Cx 0 3	Tr 6	Fe 13	T 19
Th. II Th. III Terga	Ml+Mc+mi Ml+Mc+me	Ml+Mc+mi+ s Ml+Mc+2me+s	Ml+me+s+ms Ml+ me+s	Ml+2Mcc Ml+2Mcc	2 7 2 8 Sterna	6 6	12 11	19 18
Abd. I Abd. II	Ml+Mc Ml+Mc	Ml+2me+s Ml+2me+s	Ml+ Mcc Ml+Mcc	Ml+Mcc+1me Ml+Mcc+1me	VT: 4 Ve: 4, V1: 0
Abd. III Abd. IV	Ml+Mc Ml+Mc	Ml+2me+s Ml+me+s	Ml+Mcc Ml+Mc+me	Ml+Mcc+1me 3Ml+3Mc	Ve: 4, Fu: 3–4, 0 mi Vei: 1, Vec: 4, Vel: 3, Vl: 4
Abd. V	Ml+2me	------- s+2Ml+2me -------		2Mcc+2me	Ag: 4, Vl: 2, L’: 0
Abd. VI	------------------- 4Ml+2Mc+1me ----------------------				Ve: 14, An: 3 mi