Thalassaphorura biquaternata, Sun & Li, 2015

Sun, Xin & Li, Yu, 2015, Thalassaphorurini (Collembola: Onychiuridae) in Shandong Province, China, with description of two new species, Florida Entomologist 98 (2), pp. 697-703 : 698

Thalassaphorura biquaternata sp. nov. ( Figs. 1–12 )

MATERIAL EXAMINED

HOLOTYPE female, CHINA, Shandong Province, Laiwu City, Fangxia Town, Wulongkou Village (36.2154°N, 117.4886°E), 1 Apr 2014, soil of the greenhouse planting with P.ostreatus, Xin Sun coll. (SDLW-140401) . PARATYPES 5 females, same data as holotype .

OTHER MATERIALS 2 females, CHINA, Shandong, Liaocheng City, Gaotang County, Liulisi Town (36.7142°N, 116.3403°E), 11 Apr 2014, soil of the greenhouse planting with P. ostreatus, Xin Sun coll. (SDGT-140411) .

DESCRIPTION

Body white in alcohol. Length of body 1.50–1.80 mm in females; holotype 1.75 mm. Shape of body cylindrical with anal spines on papillae. Anal spines 0.8 times as long as inner edge of hind unguis ( Fig. 1 ).

Pso formula 33/033/333(4)43 dorsally and pso absent ventrally ( Figs. 1, 2, 6 ). Subcoxae 1 of legs I–III without pso. Psx formula 01/000/ 110101 m ventrally and psx absent dorsally ( Figs. 1, 2, 6 ). Subcoxae 1 of legs I–III with 1 psx each. Psp formula 00/011/111100 dorsally and 00/111/001 m 1 m 00 ventrally ( Figs. 1, 2, 6 ).

Head. Antennae as long as head. Length ratio of Ant. I: II: III: IV about 1: 1.8: 1.8: 2.0. Subapical organite on Ant. IV with globular apex; basolateral ms above the 2nd proximal row of chaetae ( Fig. 7 ). Ant. III sensory organ consists of 4 papillae, 4 guard chaetae, 2 small rods, and 2 granulated sensory clubs; lateral ms just behind sensory organ ( Fig. 5 ). Ant. II with 14–15 chaetae. Ant. I with 9 chaetae. Antennal base well marked. PAO with 24–26 simple vesicles arranged in 2 rows along axis of organ ( Fig. 4 ). Dorsal cephalic chaeta d0 absent. Head with 4+4 p-chaetae present between 2 posterior pso, p 1 in line with others ( Fig. 1 ). Mandible with strong molar plate and 4 apical teeth. Maxilla bearing 3 teeth and 6 lamellae. Maxillary palp simple with 1 basal chaeta, without sublobal hair. Labral chaetae 4/142. Labium with 5 proximal, 4 basomedian (E, F, G, and f) and 5 basolateral (b, c, d, e, e’) chaetae ( Fig. 3 ); labial type A, papillae A–E with 1, 4, 0, 3, and 1 guard chaetae, respectively ( Fig. 3 ). Postlabial chaetae 4+4 along ventral groove ( Fig. 2 ).

Body chaetotaxy. S-chaeta not distinguishable from ordinary chaeta. Tiny and blunt ms present on Th. II and III ( Fig. 1 ). Th. I tergum with 7–9+7–9 chaetae. Th. II–Abd. II terga with 4+4 chaetae along axial line ( Fig. 1 ). Abd. III–IV terga with unpaired chaeta m0 each, Abd. V tergum with chaeta a0, Abd. VI tergum with chaeta m0 ( Fig. 10 ). Th. I, II, and III sterna with 0+0, 1+1, and 1+1 chaetae, respectively.

Appendages. Subcoxae 1 of legs I, II, and III with 5, 5, and 5 chaetae, subcoxae 2 with 1, 5, and 5 chaetae, respectively. Coxae of legs I, II, and III with 3, 9, and 12 chaetae, respectively, trochanters with 9 chaetae each, and femora with 15 chaetae each. Tibiotarsi of legs I, II, and III with 16 (1, 8, 7) chaetae each ( Figs. 8, 9 ). Unguis without teeth. Unguiculus as long as inner edge of unguis, without inner basal lamella ( Figs. 8, 9 ). Ventral tube with 5–6+5–6 distal chaetae and 2+2(1) basal chaetae, without anterior chaetae. Furca reduced to finely granulated area, with 4 small dental chaetae arranged in 2 rows posteriorly and 1 manubrial row of chaetae ( Figs. 6 , 11 ).

Female genital plate with 15–20 chaetae. Anal valves with numerous acuminate chaetae; each lateral valve with chaetae a0, 2a1, and 2a2; upper valve with chaetae a0, 2b1, 2b2, c0, 2c1, and 2c2 ( Fig. 12 ).

DERIVATIO NOMINIS

The species name refers to both the sets of 4 papillae and 4 guard chaetae on Ant. III sensory organ.

REMARKS

Thalassaphorura biquaternata sp. nov. is peculiar in the genus Thalassaphorura as having the following combined characters: posterior pso on head as 3+3, pso on Th. I tergum absent; 4 papillae and 4 guard chaetae on Ant. III sensory organ; chaeta d0 on head absent; maxillary palp without sublobal hair; 1 guard chaeta on labial papilla E, chaetae in distal row of tibiotarsi as 7. The new species shares the character “4 papillae on Ant. III sensory organ” with 4 known species: T. butrosi (Christiansen, 1956) , T. franzi (Stach, 1946) , T. cryptopyga (Denis,1931) , and T. tovtrensis (Kaprus’ & Weiner,1995). These species can be distinguished easily by the dorsal pso formulae (33/033/333(4) 43 in the new species, 32/122/ 22332 in T. butrosi , 32/133/ 33333 in T. franzi , and 32/233/ 33343 in T. cryptopyga and T. tovtrensis ). The new species is similar to the Chinese species T. problematica Sun, Deharveng & Wu, 2013 as having reduced number of chaetae in row A of the tibiotarsi (6 or 7) and none in row T, chaeta d0 on head absent, and 5 proximal chaetae in labial area. These 2 species can be distinguished by the pso formulae (33/033/333(4)43 dorsally and absent ventrally in the new species, 32/133/33343 dorsally and 11/000/00010 ventrally in T. problematica ), the ventral psx formulae (01/000/ 110101 m in the new species, 112001+ 1 m in T. problematica ), the number of papillae and guard chaetae on Ant. III sensory organ (4 and 4, respectively, in the new species, 5 and 5, respectively, in T. problematica ), the labial type (A in the new species, AB in T. problematica ), and the axial chaetae on Abd. IV–VI (m0, a0, and m0 in the new species, p0, p0, a0, and p0 in T. problematica ). The new species also shares the peculiar character “chaeta d0 on head absent” with the Indonesian species T. jailolonis (Yoshii & Suhardjono, 1992) , but it can be recognized easily by the pso formulae (32/133/33334 dorsally and 1/000/01120 ventrally in T. jailolonis ) and the absence of pso on subcoxae 1 of legs I–III (1,1,1 in T. jailolonis ).

Figures

Figs. 1–6. Thalassaphorura biquaternata sp. nov. 1. Dorsal chaetotaxy of body; 2. Ventral chaetotaxy of head; 3. Labium; 4. PAO; 5. Papillae, sensory rods, and sensory clubs of Ant. III sensory organ; 6. Chaetotaxy of Abd. II–VI sterna. Scale bars: 0.1 mm (Figs. 1, 2, 6), 0.01 mm (Figs. 3–5).

Figs. 7–12. Thalassaphorura biquaternata sp. nov. 7. Antenna; 8. Distal part of leg I; 9. Distal part of leg II; 10. Chaetotaxy of Abd. III–VI terga; 11. Chaetotaxy of Abd. IV–VI sterna; 12. Anal valves. Scale bars: 0.1 mm (Figs. 7, 10–11), 0.01 mm (Figs. 8–9, 12).