Thalassaphorura macrospinata, Sun, Xin & Wu, Dong-Hui, 2012

Sun, Xin & Wu, Dong-Hui, 2012, Two new species of tribe Thalassaphorurini Pomorski, 1998 (Collembola: Onychiuridae) from Northeast China, Zootaxa 3226, pp. 61-68 : 64-67

Thalassaphorura macrospinata sp. nov.

Figs 10–18 . Tab. 1

Type material. Holotype female, 6 female and 10 male paratypes. China: Jilin province: Changchun: Gaoxin: 30. IX.2011, litter and soil, Berlese extraction, Song Lihong and Sun Xin leg. All deposited in the Key laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun.

Description. Body color white in alcohol. Size 1.9–2.0 mm in females, 1.7–1.9 mm in males; holotype: 2.0 mm. Body cylindrical, body side parallel.

Pseudocellar formulae as 32/233/33343 dorsally, 11/000/01120 ventrally ( Figs 10, 15 & 17 ), subcoxa 1 of legs I–III with 2, 2 and 2 pso respectively. Parapseudocelli present on each side of ventral tube anteriorly to basal chaetae. Pseudopore formulae as 00/011/11110 dorsally, 00/111/000x0 ventrally ( Figs 10, 15 & 17 ).

S-chaetae cylindrical, well differentiated, formulae as 11/011/222120 dorsally, 11/000/000100 ventrally ( Figs 10, 15 & 17 ). Sp present on head. Microsensilla tiny and blunt, present on Th. II–III ( Fig. 10 ).

Head. Antennae short and distinctly segmented, as long as head or slightly longer. Length ratio of antennal segments I: II: III: IV = 1: 2: 2: 2.3. Ant. IV with indistinct S-chaetae, subapical organite with apex globular and basolateral ms at about 1/4 length from base. Ant. III sensory organ composed of 5 papillae, 5 guard chaetae, 2 small sensory rods and 2 smooth subequal clubs, and a lateral ms ( Fig. 13 ). Ant. II with 13 chaetae. Ant. I with 9 chaetae. Antennal base with distinct granulation. PAO composed 28–32 simple vesicles ( Fig. 12 ). Dorsal cephalic chaeta d0 present. 3+3 chaetae between posterior inner pso on head. Mandible with strong molar plate and 4 apical teeth. Maxilla bearing 3 teeth and 6 lamellae. Maxillary palp simple with 1 basal chaeta and 1 sublobal hairs. Labral chaetae formula 4/142. Labium with 6 proximal, 4 basomedian (E, F, G and f) and 6 basolateral chaetae (a, b, c, d, e, e’); labial papillae of AC type, papillae A–E respectively with 1, 4, 0, 3, and 2 guard chaetae ( Fig. 11 ). Postlabial chaetae 4+4 along ventral groove ( Fig. 15 ).

Body chaetotaxy. Ordinary chaetae differentiated in meso- and macrochaetae, ratio sp: m1: p1 on Abd. V = 1: 0.4: 1.7 ( Fig. 10 ). Th. I tergum with 7+7 chaetae dorsally. Th. II–Abd. III terga respectively with 3+3 chaetae on both side of axial line, without dorsal axial chaetae. Abd. IV tergum with m0 axial chaeta, Abd. V with a0 axial chaeta, Abd. VI with only m0 axial chaeta ( Fig. 7 ). Th. I, II and III sterna with 1+1, 1+1, 1+1 chaetae respectively.

Subcoxa 1 of legs I–III with 5, 4 and 4 chaetae, subcoxa 2 with 1, 4 and 4 chaetae respectively. Tibiotarsi of legs I, II and III each with 18 (1, 8, 9) chaetae. Unguis with lateral teeth. Unguiculus slender and pointed, 0.9 times as long as inner edge of unguis, without inner basal lamella ( Fig. 14 ). Ventral tube with 1+1 anterior chaetae, 6+6 distal chaetae, 2+2 basal chaetae ( Fig. 16 ). Furca reduced to a field of fine granulation with 4 small dental chaetae arranged in 2 rows posteriorly; only one manubrial row of chaetae present posteriorly to dental chaetae ( Fig.17 ).

Genital plate with 12–14 chaetae in females, 25–30 chaetae in males ( Figs 17–18 ). Male organ present, 5+5 inflated distal chaetae with thorns on ventral tube ( Fig. 16 ). Anal valves with numerous acuminate chaetae; each lateral valve with a0 and 2a1; upper valves with chaetae a0, 2b1, 2b2, c0, 2c1, 2c2 ( Fig. 17 ). Anal spines set on distinct papillae, 1.1 times as long as inner edge of hind unguis ( Fig. 10 ).

Ecology. In broadleaved litter and soil, in a recreational park in town.

Etymology. Named for its large anal spines.

Remarks. The new species is very particular as having male organ on ventral tube and only one sublobal hairs on maxillary palp.

T. macrospinata sp. nov. is similar to T. qixiaensis Yan, Shi & Chen, 2006 , but they can be distinguished by the S-chaetae (well differentiated in macrospinata sp. nov. and not differentiated in qixiaensis ), the proximal chaetae of labium (6 in macrospinata sp. nov. versus 7 in qixiaensis ), the number of chaetae on Th. I tergum (7+ 7 in macrospinata sp. nov. versus 6+ 6 in qixiaensis ), the dorsal axial chaetae on Abd.VI (m0 in macrospinata sp. nov. versus a0 & m0 in qixiaensis ), the number of chaetae on subcoxa 1 of legs I (5 in macrospinata sp. nov. versus 4 in qixiaensis ), the position of male organ (5+5 inflated distal chaetae on distal ventral tube in macrospinata sp. nov. versus 6–12 short, broad and thin with apex pointed chaetae on Abd. II and 7–10 on Abd. III in qixiaensis ), and the ratio of anal spines/inner edge of hind unguis (1.1 in macrospinata sp. nov. versus 0.8 in qixiaensis ).

T. macrospinata sp. nov. belongs to the group including T. encarpata ( Denis, 1931) , T. lifouensis ( Thibaud & Weiner, 1997) , T. petaloides ( Rusek, 1981) , T. qixiaensis Yan, Shi & Chen, 2006 , T. tenuis Babenko, 2007 , T. thaibinhensis ( Nguyen, 2001) , T. tiani Sun, Chen & Deharveng, 2010 , T. tibiotarsalis Sun, Chen & Deharveng, 2010 , T. zschokkei ( Handschin, 1919) , with pseudocellar formulae as 32/233/33343 dorsally and 11/000/01120 ventrally. The mainly combined characters to separated them are shown in Table 1 .

* T. petaloides : data from personal examination on the specimens of China (Guangxi: Fushui, Longzhou and Huangjiang) preserved in the Museum national d’Histoire naturelle (Paris, France). T. zschokkei : data from the description in Pomorski (1998).

Figures

FIGURES 10 – 15. Thalassaphorura macrospinata sp. nov.: 10, dorsal chaetotaxy; 11, labial palp; 12, PAO and anterior cephalic pso; 13, antenna; 14, distal part of leg III; 15, ventral side of head. Scales: 0.1 mm (10 & 13 – 15), 0.01 mm (11 – 12).

FIGURES 16 – 18. Thalassaphorura macrospinata sp. nov.: 16, ventral tube; 17, ventral side of Abd. II – VI; 18, male genital plate. Scales: 0.1 mm.

FIGURES 1 – 7. Sensillonychiurus changchunensis sp. nov.: 1, dorsal chaetotaxy; 2, antenna; 3, PAO and anterior cephalic pso; 4, labium; 5, ventral side of head; 6, distal part of leg III; 7, legIII. Scales: 0.1 mm (1 & 7), 0.01 mm (2 – 6).

Tables

TABLE 1. Comparison of species having the same pseudocellar formula (32 / 233 / 33343 dorsally and 11 / 000 / 01120 ventrally) in Thalassaphorura.

	Number of chaetae in distal whorl of tibiotarsi	Number of chae- tae between pos- terior inner pso on head	Ratio of AS/ unguis	Inner basal lamella on unguiculus	Number of vesi- cles in PAO	Dorsal S-chaetae formula	Labial type	Axial chaetae on Abd. VI
macrospinata sp. nov.	9	3+3	1.1	absent	28–32	11/011/222120	AC	m0
encarpata	9	3+3	0.8	absent	22–25	indistinct	A	a0, m0
lifouensis	9	4+4	0.5	present	17–23	10/011/222120	AC	a0, m0
petaloides	7*	3+3	1.0	present	18–21	10/011/221121	AC	a0, m0
qixiaensis	9	3+3	0.8	absent	21–30	indistinct	AC	a0, m0
tenuis	9	3+3	0.4	absent	11–13	11/011/111010	ABC	a0
thaibinhensis	?	3+3	0.9	absent	20	10/???/??????	?	a0, m0
tiani	9	3+3	1.0	present	24–26	11/011/222120	AC	a0, m0
tibiotarsalis	7	3+3	0.7	present	17–18	11/011/222120	ABC	a0
zschokkei	9	3+3	0.7	present	24–28	indistinct	AC	a0*