Sensiphorura oligoseta, Bu, Yun, Potapov, Mikhail B. & Gao, Yan, 2013

Bu, Yun, Potapov, Mikhail B. & Gao, Yan, 2013, A new species and new records of Pachytullbergiidae and Tullbergiidae (Collembola: Onychiuroidea) from littoral of China, with notes on the variations of postantennal organ, Zootaxa 3669 (2), pp. 139-146 : 140-142

Sensiphorura oligoseta sp. nov.

Figs 1–9 , Tab. 1–2

Materials examined. Holotype: female, South China, Hainan Province (western coast), Changjiang County, vicinity of Changhua town, Qizi Bay, 19°21' N 108°40'E, sand beach, flotation of sand samples (No. 54). 7.iv.2011, C. W. Huang, M.B. Potapov, N. A. Kuznetsova, and Y. Bu, leg. Paratype: 1 female (No. 56), same as holotype. 1 female, South China, Hainan Province, Ledong county, Mt. Jianfeng, 18°43' N 108°54'E, alt. 220 m, soil of semideciduous seasonal rainforest, 14.i.2004, Y. Xiong leg. Holotype and 1 paratype are deposited in Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, CAS ( China), 1 paratype is deposited at Moscow State Pedagogical University.

The material of S. marshalli : seven specimens from Canada, Vancouver Island, from thick spongy hemlock litter on top of plateau, 31.v.1983, A. Fjellberg leg.

Description. Holotype length 480 μm, width 120 μm. White in alcohol, without pigmentation, no eyes. Pseudocelli not visible in light microscope. Secondary granulation present, primary granulation fine. Body setae short, few of them on the ventral side longer than others ( Figs 2, 3 ).

Antennae shorter than head (1: 1.6). Antennal segment III and IV fused. Ant. I and II with 7 and 11 setae respectively. Antennal organ of III well developed ( Figs 8, 9 ), with two separate parts. Dorsal part composed of one large bent sensory club, one small sensory rod covered by club, five or six subequal, slim protecting papillae, and four protecting setae. Some papilla fused together at base ( Fig. 8 ). Ventral part consists of one large bent sensory club, one small sensory rod covered by club, three slim protecting papillae, and three protecting setae. Ventral protecting setae and several others with 1–2 cilia (more setae probably have cilia than shown on Figs 8 and 9 ). Ant. IV with 11 cylindrical sensilla, two bulb-shaped sensilla, and one small apical vesicle, subapical microsensillum not observed.

Postantennal organ hidden in groove formed by integumentary folds and composed by eight to nine simple vesicles lying side by side in two parallel rows, with 4 setae behind them ( Fig. 1 ).

Head with seta a0 and c1 ( Fig. 2 ). Mouthparts well-developed. Labium generally as in S. marshalli (Fig. 41 in Fjellberg, 1999) with 4 papilla, 2 long guards (short guards not seen), 3 proximal setae, 4 basomedian setae, and 5 basolateral setae. Mandibles and maxilla as in S. marshalli .

Dorsal chaetotaxy shown in Fig. 2 and Table 1 . Th. II–Abd. IV with 2+2 axial setae each. Number of lanceolate sensory chaetae s on dorsal side as 2, 2/2, 4, 4, 4, 5, 1 ( Fig. 5 ), microsensilla present on Th. II-III. Seta a2 absent on tergites of Abd. I-III. Subcoxa with 0, 2+1s, 2+1s setae, coxa with 3, 6, 6 setae, trochanter with 5, 5, 4 setae, femur with 10, 10, 9 setae, and tibiotarsus with 11, 11, 11 setae on leg I, II and III, respectively; without tenent hairs ( Fig. 7 ). Without empodial appendage. Thorax without ventral setae.

1 seta a2 absent; 2 seta m5 present; 3 10 anterior setae, 5 setae on genital plate and 2 posterior sensory chaetae s

Chaetotaxy of ventral side of abdomen shown in Fig. 3 and Table 1 . Ventral tube with 5+5 setae (4+ 4 in distal and 1+ 1 in basal position, Fig. 6 ). Abd. IV with 4 longitudinal rows of ventral setae. Without furca and retinaculum. Female genital plate with 5 setae in front of it and one proximal lateral sensory chaeta. Anal spines small, four times shorter than claw III.

Males unknown.

Remarks. Sensiphorura oligoseta is the second member of the genus. It differs from the type species S. marshalli by characters shown in Table 2 . The most important characters are small vesicle on Ant. IV (vs. large), differentiation of sensory chaetae s on body ( Figs 4, 5 ), and absence (vs. presence) of a2 seta on Abd. I–III.

Etymology The new species has fewer setae on abdominal tergites.

Distribution and ecology. The species is known only from two localities of Hainan (SE China), from the dunes of the beach and tropical forest. Type species of the genus, S. marshalli , was found in the litter of old coast western hemlock forest. Habitat of the holotype was shown in Potapov et al. (2011, Fig. 9 ).

Remarks. The records of Pachytullbergiidae (Pachytullbergiinae in the past) in the world are scanty and its systematic position remains unclear and controversial (Stach 1954; Salmon 1959; Cassagnau & Rapoport 1962; Rusek 1976). Deharveng (2004) transferred Pachytullbergiinae to Hypogastruroidea and ranked it as a family ( Pachytullbergiidae ). Many taxonomists, however, still incline to place it into superfamily Onychiuroidea like it is accepted in Bellinger et al. 1996–2012. We deem Pachytullbergiidae as a member of superfamily family Onychiuroidea in the present paper, because the similarity of postantennal organ as well as the sensilla on antenna between them. We suppose that at least one of the genera of the family, Sensiphorura , is rather common in Asia but it is likely overlooked in the materials because of small body size.

Figures

FIGURES 1 – 7. Sensiphorura oligoseta sp. nov. (1 – 3, 5 – 7) and S. marshalli (4): 1, PAO; 2, dorsal chaetotaxy of body; 3), ventral chaetotaxy of abdomen; 4 – 5, dorsal sensory chaetae patterns, 6, ventral tube; 7, leg III; s –– sensory chaeta.

FIGURES 8 – 9. Sensiphorura oligoseta sp. nov., antennal segments III and IV: 8, dorsal view; 9, ventral view; av –apical vesicle.

Tables

TABLE 1. Body chaetotaxy of Sensiphorura oligoseta sp. nov.

		Thorax		Abdomen
Segments		I II	III	I II	III	IV V
Dorsal	a	- 6	6	8 1 8 1	8 1	8 8
	m	8 6	6	2 2 2 2	2 2	2 2 -
	p	- 8	8	10 10	10	8 7
	pl	1 2	2	1 3	3	6 1
Ventral		0 0	0	10 14	14	28(26) 10+5+2s3

TABLE 2. Comparison of characters between Sensiphorura oligoseta sp. nov. and S. marshalli.

Species	S. oligoseta sp. nov.	S. marshalli
Distribution	South China	West Canada
papilla of Ant.III ventral organ	all subequally long	two long and one short
apical vesicle of Ant. IV	small	large
p3 of Th. II-III	slightly thickened	lanceolate
a2 of Abd. I-III	absent	present
m3 of Abd. IV	absent	present
lanceolate sensory chaeta s of Abd. I	p5	p3
lanceolate sensory chaeta s of Abd. III	p3, 5	p3