Sinella abietis, Ding, Yin-Huan & Zhang, Feng, 2015

Ding, Yin-Huan & Zhang, Feng, 2015, Contribution to the eyed Sinella from China: two new species and additional reports on nine known species (Collembola: Entomobryidae), Zootaxa 3973 (3), pp. 474-490 : 475-483

Sinella abietis sp. nov.

Figs 1, 11– 27, Table 1

Types. Holotype: male on slide, China: Zhejiang Province: Qingyuan County: Baishanzu Natural Reserve, alt. 1149 m, 27.739 °N, 119.179 °E, 22.v. 2011, Feng Zhang and Daoyuan YU leg. (# C 9662). Paratypes: three females on slides, same data as holotype.

Description. Body length up to 1.33 mm. Body light orange in alcohol ( Fig. 1).

Antenna 1.8 of cephalic diagonal length. Antennal segments ratio as I: II: III: IV = 1: 1.67–1.87: 1. 27–1.53: 2.67–2.93. Smooth spiny mic at base of antennae 3 dorsal, 3 ventral on Ant. I, 1 internal, 1 external and 1 ventral on Ant. II. Ant. II distally with 1 sens having basal part expanded ( Fig. 11). Two internal sens of Ant. III organ paddle-like; chaeta 8 dagger-like ( Fig. 12). Ant. IV with a knobbed subapical organ ( Fig. 13); 2 extero-dorsal short sens as those on Ant. II distally ( Fig. 11), 0.17 and 0.45 distance from the apex, respectively. Long smooth straight chaetae absent on antennae.

Eyes 1 + 1. Prelabral and labral chaetae 4 / 5, 5, 4, all smooth; the five chaetae of the first row subequal in length. Seven ciliate clypeal chaetae arranged in two rows ( Fig. 14). Dorsal cephalic chaetotaxy with 4 antennal, 3 median (M) and 5 sutural (S) mac; Gr. II with 3–4 mac ( Fig. 15). Subapical chaeta of maxillary outer lobe slightly thicker than apical one; 3 smooth sublobal hairs on maxillary outer lobe. Lateral process of labial palp as thick as normal chaetae, with tip not reaching apex of labial papilla ( Fig. 16). Labial chaetae as mrel 1 l 2, all smooth, r/m= 0.8; chaetae X, X 2, X 4, H 1, and H 4 ciliate. Chaetae along cephalic groove 6–7, the proximal one smooth and others ciliate ( Fig. 17).

Trochanteral organ with 12–16 smooth spiny chaetae; 10–13 in arms and 2–4 between them ( Fig. 18). Inner differentiated tibiotarsal chaetae ciliate with ciliations not closely appressed to axis. Tibiotarsi distally with 11 chaetae in a whorl. Unguis with 3 inner teeth; 2 paired teeth unequal, outer one large. Unguiculus outer edge smooth. Tenent hairs pointed ( Fig. 19). Abd. IV 3.2–5.1 of Abd. III dorsal midline length. Ventral tube anteriorly with 6 + 6 ciliate chaetae and 1 + 1 pseudopore; two of them much larger than others ( Fig. 20); posteriorly with 14 chaetae, 4 apical ones smooth and others weakly ciliate; each lateral flap with 7 smooth and 2 ciliate chaetae ( Fig. 21). Manubrium without smooth chaetae. Manubrial plaque with 3 + 3 pseudopores and 3 + 3 ciliate chaetae ( Fig. 22). Distal smooth part of dens 2.0 of mucro length. Mucro bidentate with two teeth subequal; basal spine reaching tip of the subapical tooth ( Fig. 23).

Th. II with 3 (m 1, m 2, m 2 i) medio-medial, 3 (m 4, m 4 i, m 4 p) medio-lateral, 24–25 posterior mac, 1 ms and 2 sens; ms inner to sens. Th. III with 25–26 mac and 2 lateral sens; a 6 i, p 6 and m 6 as mac ( Fig. 24). Abd. I with 6 (a 3, m 2–4, m 2 i, m 4 p) mac, 1 ms and 1 sens; sens inner to ms. Abd. II with 3 (m 3, m 3 e, m 3 ep) central, 1 (m 5) lateral mac and 2 sens. Abd. III with 1 (m 3) central, 2 (pm 6, p 6) lateral mac and 2 sens; ms absent ( Fig. 25). Abd. IV with 4 central (M, B 5, B 6, A 6) and 6 lateral mac (D 3, E 2–4, E 2 p, F 1) ( Fig. 26); two sens (as, ps) of normal length and others elongate. Abd. V with 3 sens ( Fig. 27).

Ecology. Leaves in decomposition along the roads.

Etymology. Named after the famous national key protected wild plants Abies beshanzuensis in natural reserve.

Remarks. S. abietis sp. nov. is characterized by 1 + 1 eyes, paddle-like sens of Ant. III organ, ciliate clypeal chaetae, ciliate chaetae X, X 2, X 4, H 1, and H 4 posterior to labium, 2 + 2 lateral mac on Abd. III, 4 + 4 central mac on Abd. IV, and smooth outer edge on unguiculus. It is most similar to S. affluens Chen & Christiansen, 1993 , but differs from it in having ciliate H 4, X, and X 4 posterior to labium, smooth outer edge on unguiculus, short mucronal spine, three pseudopores on manubrial plaque, 2 + 2 lateral mac on Abd. III, and chaetotaxy of Abd. IV. The new species differs from another 1 + 1 eyed species S. fuyanensis in having paddle-like sens of Ant. III organ, ciliate H 4, X, X 2, and X 4 posterior to labium, 3 + 3 chaetae and 3 + 3 pseudopores on manubrial plaque, longer smooth part of dens, p 5 as mic on Th. III, 2 + 2 lateral mac on Abd. III, and 4 + 4 central mac on Abd. IV ( Table 1).

Types. Holotype: female on slide, China: Shanxi Province: Mishui county: Zhongshan town: Lishan National Natural Reserve, alt. 1469 m, 35.42806 °N, 112.00194 °E, 11.ix. 2013, F. Zhang leg. (# 13 SXLS 2). Paratype: female on slide, alt. 1494 m, 35.43556 °N, 112.01194 °E, 12.ix. 2013 (# 13 SXLS 4), other data same as holotype.

Description. Body length up to 1.07 mm. Orange pigments weakly scattered on head and body ( Fig. 2).

Antenna 1.5–1.9 of cephalic diagonal length. Antennal segments ratio as I: II: III: IV = 1: 2.0: 1. 4: 3.7. Smooth spiny mic at base of antennae 3 dorsal, 3 ventral on Ant. I, 1 internal, 1 external and 1 ventral on Ant. II. Ant. II distally with 1 rod-like, unexpanded sens. Two internal sens of Ant. III organ rod-like; chaeta 8 posterior to chaeta 9 ( Fig. 28). Long smooth straight chaetae absent on antennae.

Eyes 1 + 1. Prelabral and labral chaetae 4 / 5, 5, 4, all smooth. Clypeal chaetae 8, all ciliate ( Fig. 29). Dorsal cephalic chaetotaxy with 4 antennal, 3 median (M) and 4 sutural (S) mac ( Fig. 30). Subapical chaeta of maxillary outer lobe thicker than apical one; 3 smooth sublobal hairs on maxillary outer lobe ( Fig. 31). Lateral process of labial palp as thick as normal chaetae, with tip beyond apex of labial papilla ( Fig. 32). Labial chaetae as mRel 1 l 2, all smooth except R, R/m= 0.7; chaetae G 1-3 smooth and others ciliate. Cephalic groove with 7 chaetae, 1 (G 1) of them smooth ( Fig. 33).

Trochanteral organ with 10–12 smooth spiny chaetae; 7–9 in arms and 3 between them. Inner differentiated tibiotarsal chaetae ciliate with ciliations not closely appressed to axis. Tibiotarsi distally with 10 ciliate chaetae in a whorl. Unguis with 3 inner teeth; 2 paired teeth unequal, outer one large. Unguiculus outer edge with a large tooth. All tenent hairs pointed ( Fig. 34). Abd. IV 2.4–2.6 of Abd. III dorsal midline length. Ventral tube anteriorly with 2 + 2 large and 4 + 4 small ciliate chaetae ( Fig. 35); posteriorly with 9 (3, 2, 4 in three rows) chaetae, the extero-apical two ciliate ( Fig. 36); each lateral flap with 7 chaetae, 3 of them ciliate ( Fig. 35). Manubrium without smooth chaetae. Manubrial plaque with 2 + 2 pseudopores and 2 + 2 ciliate chaetae. Distal smooth part of dens 2.3–2.7 of mucro length. Mucronal basal spine nearly reaching tip of the apical tooth ( Fig. 37).

Th. II with 4 (m 1, m 2, m 2 i, m 2 i 2) medio-medial, 3 (m 4, m 4 i, m 4 p) medio-lateral, 18–20 posterior mac, 1 ms and 2 sens; ms internal to sens; mac p 2 ep 2 often absent. Th. III with 25 mac and 2 lateral sens; mac a 6 i and m 5 i absent ( Fig. 38). Abd. I with 6 (a 3, m 2–4, m 2 i, m 4 p) mac, 1 ms and 1 sens; ms inner to sens. Abd. II with 5 (a 2, a 3, m 3, m 3 e, m 3 ep) central, 1 (m 5) lateral mac and 2 sens. Abd. III with 2 (a 2, m 3) central, 1 (pm 6) lateral mac and 2 sens. Abd. IV with 4 central (M, B 5–6, A 4), 5 lateral mac (D 3, E 2–4, F 1) and at least 9 sens; two sens of normal length and others elongate ( Fig. 39). Abd. V with 3 sens ( Fig. 40).

Ecology. In rotten leaves of forest.

Etymology. Named after the 1 + 1 lateral mac on Abd. III.

Remarks. S. uniseta sp. nov. is the eighth species with 1 + 1 eyes from China ( Zhang, 2013). It is characterized by the reverse position of chaetae 8 and 9 on Ant. III, 4 sutural cephalic mac, 1 + 1 lateral mac on Abd. III, and unique 4 + 4 central and 5 + 5 lateral mac on Abd. IV. It is most similar to S. affluens Chen & Christiansen, 1993 in 1 + 1 eyes, long mucronal spine nearly reaching the tip of the apical tooth and claw structure, but differs from the latter in having ciliate chaetae posterior to G 1-3, Ant. III organ, absence of mac a 6 i on Th. III, 5 + 5 central mac on Abd. II, 2 + 2 central and 1 + 1 lateral mac on Abd. III, unique arrangement of central mac on Abd. IV, and pointed tenent hair.

Tables

TABLE 1. Comparison among the four 1 + 1 eyed species of Sinella (?, unknown; +, present; –, absent; lp, lateral process of labial palp;>, tip beyond apex of labial papilla; <, tip not reaching apex of labial papilla; s, smooth chaeta, - tae; c, ciliate chaeta, - tae).

Characters	S. abietis sp. nov. S. uniseta sp. nov. S. affluens	S. fuyanensis
Two sens of Ant. III organ	paddle-like rod-like paddle-like	rod-like
Clypeal chaetae	7c 8c 7c	?
Lp	<> =	>
Labial chaetae R R/M	s c s 0.8 0.7 0.66	s 0.13–0.17
Chaetae posterior to labium X X2 X4 G4 H1,4 H2,3 Chaetae on trochanteral organ	c c s, mic c c – c c s, mic s c s c c s s c s 12–16 10–12 13–14	s, mic s, mic s, mic s s s ≈23
Unguiculus outer edge	smooth a large tooth a large tooth	smooth
Differentiated tibiotarsal chaetae	c c c	“smooth”
Ventral tube One side of anterior face Posterior face Lateral flap	6c 6c 5–6c 14 7s2c 8–9s 7s2c 4s3c 6–7s	8c 10–19 6–8s
Manubrial plaque Pseudopores Ciliate chaetae	3 2 2(3) 3 2 3(2)	2(3) 4–7
Uncrenulate dens/mucro	2.0 2.3–2.7 2.0–2.5	≈1
Mucronal spine	short long long	short
Sutural mac on dorsal head	5 4 5	5
Gr. VI on Th. II	3 2 1	2
Mac a6i on Th. III	+ – +	+
Central mac on Abd. II	3 5 3	3
Central mac on Abd. III	1 2 1	1
Lateral mac on Abd. III	2 1 3	3
Central mac on Abd. IV	4 4 4	6
Lateral mac on Abd. IV	6 5 4	6
Sinella uniseta sp. nov. Figs 2, 28–40, Table 1