Sensiphorura anichkini, Shveenkova, 2017

Shveenkova, Yulia B., 2017, New Collembolan species of the genera Sensiphorura Rusek, 1976 (Pachytullbergiidae) and Cephalachorutes Bedos & Deharveng, 1991 (Neanuridae) from Southern Vietnam, Zoosystema 39 (1), pp. 75-85 : 79-82

Sensiphorura anichkini n. sp.

( Fig. 3 ; Tables 2-4)

TYPE MATERIAL. — Holotype. ♀ juv., Southern Vietnam, Province Dong Nai, Cat Tien National Park , 18.XI.2005, forest of Dipterocarpus alatus on a basalt ridge, soil, c. 149 m a.s.l., Yu. Shveenkova leg., deposited in MSPU.

Paratypes. 3 ♀, same data as holotype.

Other material. 1 juv., same data as holotype, but forest of Tetrameles nudiflora R.Brown , 2.XI.2005 ; deposited in MNHN.

DIAGNOSIS. — Apical vesicle small and globular. Ventral AIIIO consisting of one large sensory club, one sensory rod, 3 long papillae and 3 protecting chaetae. Sensilla s and lateral microsensilla ms present on both Th. II-III. Abd. I without a2 chaetae. M3 chaetae present on Abd. IV (only adult specimens) and a2 chaetae on Abd. II-III (last character variable among juveniles and adult specimen too). Sensilla on body: p3 on Th. II-III and Abd. I differentiating as slightly thickened sensilla; lanceolate sensilla present on abdomen dorsally (p3 – Abd. II-V, p5 – Abd. II-V, a0 – Abd. VI); and 1 + 1 on Abd. V ventrally. Lower subcoxa I-III with 0, 1 + 1s, 2 + 1s (juveniles with 0, 1 + 1s, 1 + 1s) chaetae.

E TYMOLOGY. — The species is named in honor of Alexander Anichkin, who investigated soil invertebrates (macrofauna) in Cat Tien National Park and kindly collected some studied material of the new collembolan species.

DESCRIPTION

General

Holotype length 505 µm, color white, without pigmentation. Body shape cylindrical, granulation of integument very fine and uniform. Pseudocelli not visible. PAO usually consisting of 10 vesicles (varies from 8 to 12) lying in two parallel rows, with 4 chaetae behind them ( Fig. 3A ). Anal spines short, set on small papillae.

Antennae

Antennae about as long or slightly shorter than head ( Fig. 3A ). Antennal segments III and IV almost fused, ventro-medial division more or less distinct. Apical part of antennae with 14 blunt sensilla: 2 short and thick on dorsal side, and 12 long and slim (five lateral and seven medial ones). Apical vesicle small and globular. Two microsensilla and small subapical organite present on apical part of antennae. Dorso-lateral antennal organ III as in Onychiuridae , with one large sensory club, one sensory rod, 4 (5) long cuticular papillae (one of papillae often strongly bifurcate making expression of additional papilla, although only 4 papilla basements always observed) and 3 protecting chaetae. Similar structure (ventral AIIIO, consisting of one large sensory club, one sensory rod, 3 long papillae and 3 protecting chaetae) present ventrally. Ventral part of antennae with hillock formation of cuticle (tubercles) with 1-3 chaetae, which form a semicircle near ventral antennal organ. Ant. I and Ant. II with 7 and 11 chaetae, respectively. Antennae as in S. tiunovi n. sp.

PAO usually consisting of 10 vesicles (varies from 8 to 12) lying in two parallel rows, with 4 chaetae behind them ( Fig. 3A ). Head with chaetae a0 and c0, without d0.

Mouthparts

Mouthparts well-developed. Labium generally as in S. marshalli ( Fjellberg 1999: fig. 41) with 4 papilla (A-D), 2 long guard chaetae (b3, b4), 3 short guard chaetae (a1, b1, b2 – very small and reduced), 3 small hypostomal and 3 proximal chaetae present. Basomedian and basolateral fields with 4 and 5 chaetae, respectively. Mandibles and maxilla as in S. marshalli .

Chaetotaxy

Head with chaetae a0 and c0, without d0. Dorsal chaetotaxy with frequent asymmetries ( Fig. 3A ); incomplete in juveniles: dorsal chaetae p1 on Abd. I-IV, m2 on Th. II-III, a2 on Abd. II-III and some other chaetae usually absent ( Table 4). Full composition of chaetae (chaetom pattern) more commonly found in adult specimens (see Table 2). Sensilla s and lateral microsensilla ms present on both Th. II-III. Chaetotaxy of Abd. VI as on fig. 3A. A0 is sensilla, it is as long as a1 and a2 chaetae. Ventral chaetotaxy as on Fig. 3B, C . Abd. IV with 4 rows of chaetae. VT with 4 + 4 proximal chaetae and 1+ 1 on the basis. 1+ 1 sensilla present on Abd. V ventrally.

Legs

Upper subcoxa I-III with 1, 2, 2 chaetae respectively. Lower subcoxa I-III with 0, 1 +1s, 2+ 1s chaetae (juveniles with 0, 1+ 1s, 1+ 1s chaetae). Ti with 11, 11, 10 chaetae on leg I, II, III, respectively, without empodial appendage, claw without teeth.

REMARKS

Sensiphorura anichkini n. sp. is very close to previous species Sensiphorura tiunovi n. sp. ( Table 3). They clearly differ by lateral microsensilla ms on Th. III (absent in S. tiunovi n. sp. and present in S. anichkini n. sp.). Less important differences are: chaetae on lower subcoxa of the second legs (1 + 1s in S. anichkini n. sp. versus 2 +1s in S. tiunovi n. sp. only in adult specimens); p5 on Abd. I (lanceolate in S.tiunovi n. sp. or normal in the second species) ( Table 4). Last difference needs to be verified with more specimens.

Sensiphorura anichkini n. sp. differs also from S. marshalli by small apical sensory club, absence of a2 chaetae on Abd. I, details of dorsal sensory chaetom (differentiation of p3, p5 as normal chaeta versus sensilla), structure of ventral AIIIO. Contrary to S. oligoseta , new species have m3 chaetae on Abd. IV and a2 chaetae on Abd. II-III (last character variable), also only one chaetae on lower subcoxa of the second leg (1 + 1s in S. anichkini n. sp. ore 2 + 1s in S. oligoseta ).

Superfamily NEANUROIDEA Massoud, 1967

Figures

FIG. 3.— Sensiphorura anichkini n. sp.: A, dorsal chaetotaxy (lateral and subcoxal chaetae separated by a dotted line; marked in circle: p5 on Abd. I, a2 on Abd. II-III, m3 on Abd. IV); B, ventral chaetotaxy of head; C, ventral chaetotaxy of abdomen (lateral chaetae by a dotted line). Abbreviations: see Material and methods. Scale bars: 0.05 mm.