Yuukianura judithae, Deharveng & Palacios-Vargas & Bedos, 2017

Deharveng, Louis, Palacios-Vargas, José G. & Bedos, Anne, 2017, A list of Yuukianura Yosii, 1955 species of the world (Collembola: Neanuridae: Neanurinae: Lobellini), with description of a new species of unusual ecology from Santo Island (Vanuatu), Zoosystema 39 (1), pp. 55-67 : 58-64

Yuukianura judithae n. sp.

( Figs 1-6 ; Table 1)

TYPE MATERIAL. — Holotype. ♀ on slide: Vanuatu: Sanma: Santo Island: Sara, Gouffre de Rotal , 9.IX.2006, cave, on bat guano, by hand, Josiane Lips leg. (167.0584667E, 15.2528S; alt. 250 m) (SK06-09-13).

Paratypes. Same data as holotype, by hand, 12 specimens on slides (3 ♂, 8♀, 1 juveniles) and about 400 in alcohol (SK06-09-11, SK06- 09-12 and SK06-09-13) ; same data as holotype, Berlese extraction of guano, one specimen on slide and about 600 in alcohol, (SK06-09- 06, SK06-09-08, SK06-09-09 and SK06-09-10). — 21.VIII.2005, cave, guano, by hand, Josiane Lips leg. Four specimens on slides and about 16 in alcohol (SK05-Lips44) .

MATERIAL DEPOSIT. — Five paratypes on slides and 20 paratypes in alcohol in the Laboratory of Ecología y Sistemática de Microartrópodos , Faculty of Sciences, Universidad Nacional Autónoma de México ; 20 paratypes in alcohol in the Department of Invertebrate Biology , Evolution and Conservation , Institute of Environmental Biology, University of Wrocław ( Poland) ; holotype and remaining paratypes in the Muséum national d’Histoire naturelle, Paris ( France) .

OTHER MATERIAL. — Vanuatu. Sanma: Aoré island, 4.IX.2006, forest, litter, Berlese extraction, Josiane Lips and Vincent Prié leg. five specimens (SK06-04-02 and SK06-04-08, 167.1611E, 15.55651667S; alt. 15 m). — Santo Island . Boutmas, Grotte Fapon (166.9648833E, 15.33101667S; alt. 380 m), on guano in the cave, 28.X.2005, by hand, Franck Brehier leg., about 30 specimens (SK05- Brehier 06) ; same data, 5.IX.2006 and 12.IX.2006, by hand, Josiane Lips leg, about 40 specimens (SK06-05-03 and SK06-12-02) ; same data, 8.IX.2006, by hand, Louis Deharveng and Cahyo Rahmadi leg., 2 specimens (SK06-08-09) ; same data, 5.IX.2006, Berlese extraction, Louis Deharveng and Anne Bedos leg., 4 specimens (SK06- 05-07 and SK06-05-08). — Boutmas, dolines of the Grotte Fapon system, 5.IX.2006, litter, Berlese extraction, Louis Deharveng and Anne Bedos leg., 2 specimens (SK06-05-10) ; same data, 8.IX.2006, litter, Berlese extraction after sifting, Louis Deharveng and Cahyo Rahmadi leg., 2 specimens (SK06-08-17). — Boutmas, near Mérié pond, 27.IX.2006, forest, litter, Berlese extraction, Louis Deharveng and Anne Bedos leg., 14 specimens (SK06-27-13). — Boutmas, Wanror (166.9541167E, 15.39305S; alt. 370 m), 12.IX.2006, forest, litter and rotten wood, Berlese extraction, Josiane Lips leg., 13 specimens (SK06-12-08, SK06-12-10 and SK06-12-12). — Funafus, Gouffre Tarius (167.0201167E, 15.53066667S; alt. 250 m), 14.IX.2006, cave, by hand and Berlese extraction of guano, Josiane Lips leg., 16 specimens (SK06-14-09 and SK06-14-13). — Loru (167.145204E, 15.141810S), 24.IX.2006, forest, litter, Berlese extraction and sifting, Louis Deharveng and Anne Bedos leg., 18 specimens (SK06-24-14 and SK06-24-18). — Matantas (166.924E, 15.177S; alt. 45 m), 14.IX.2006, forest, litter, Berlese extraction, Louis Deharveng and Anne Bedos leg., 83 specimens (SK06-14-24, SK06- 14-26, SK06-14-27, SK06-14-31 and SK06-14-33). — Nambel, near Grotte d’Amarur (167.0610833E, 15.45783333S; alt. 229 m), 6.IX.2006, forest, litter, Berlese extraction, Cahyo Rahmadi leg., 11 specimens (SK06-06-06, SK06-06-08, SK06-06-10 and SK06- 06-11). — Natawa, small blue hole near the Nanda Blue Hole (167.169E, 15.31283333S; alt. 13 m), 13.IX.2006, forest, soil, Berlese extraction and washing, Louis Deharveng and Anne Bedos leg., 6 specimens (SK06-13-17 and SK06-13-20). — Natawa, on the hill (167.183167E, 15.2962S), 21.IX.2006, forest, litter and soil, Berlese extraction, Louis Deharveng and Anne Bedos leg., 45 specimens (SK06-21-14, SK06-21-16, SK06-21-17, SK06-21-19, SK06-21-20, SK06-21-22, SK06-21-26, SK06-21-28 and SK06- 21-29). — Surunda, CTRAV (167.2070E, 15.4502S; alt. 30 m), 2.IX.2006, garden, litter, Berlese extraction, Louis Deharveng and Anne Bedos leg., 2 specimens (SK06-02-17b). — Penaoru, 11-13. XI.2006, forest, pitfall trap, 2 specimens (VAN06-P157) .

ETYMOLOGY. — The new species is named in honour of Judith Najt, for her important contribution to the knowledge of Neanuridae Collembola.

DISTRIBUTION AND ECOLOGY. — The genus Yuukianura includes several forms linked to wet habitats along streams or seashore of Asian and Pacific regions, with a single species recorded from caves until now: Y. hawaiiensis n. comb. from Hawaii ( Christiansen & Bellinger 1992). The new species described here, Yuukianura judithae n. sp., is very frequent in forest soil and litter at least on the karstic part of Santo island. But it can cope as well with cave environment where it is found foraging in very large number on fresh guano of bats or swiftlets ( Deharveng et al. 2011a, b; fig. 1A), an ecology unknown so far in other Neanuridae of the world. The species was found in six different caves of the island, often in very large populations. Conversely, the new species was not collected from seashore habitats of the same island ( Thibaud 2009), nor from the mangroves sampled by the first author, which are the most usual habitats for species of genus (Deharveng & Bedos 2011). The gut of the specimens from the type locality contained diverse figured material, including often many scales that probably come from Tineidae moths, frequently present as larvae in the guano, and as adults on the guano. The assumed adaptive shift from seashore or wet habitats to forest litter and moreover to guano, an extreme habitat in many respects ( Mulec et al. 2016), implies considerable ecophysiological changes, and is noticed here for the first time among Collembola.

DESCRIPTION

General

Length (antennae excluded): 2003 (1800-2250) µm measured in ethanol (n = 12). Holotype: 2.2 mm measured in ethanol, 2.8 mm measured on slide. Colour whitish alive and in alcohol, body elongate, narrow, parallel-sided and flattened ( Fig. 1 ). Eyes absent.

Cuticular ornementation ( Fig. 3 )

Granulation and tubercles. Body cuticle with fine and regular secondary granules, smaller than chaetal sockets. Tubercles inconspicuous or indicated by weak integument swellings associated to slight modification of the granulation (secondary granules slightly larger or less regularly arranged, and more prominent in tubercles). No tertiary granulation, no reticulations. Tubercles Oc well developed on head, De and (L + So) faint but distinct. On the tergites, tubercles faint or absent on Th. I; from Th. II to Abd. IV, tubercles Di not differentiated, De poorly differentiated and small, DL more distinct, L poorly differentiated. On Abd. I-V, tubercles De shifted towards DL.

Buttonhole structures distinct on head, Abd. I and Abd. IV, indicated by a fuzzy group of enlarged granules between Oc and De tubercles on head, and an additional small boss postero-external to De and DL tubercles on tergites.

Pseudopora of large size, oval to triangular, finely porous, present on head, subcoxae 2, tergites and sternites according to a fix pattern: one ventrally on head near each antennal basis; one basally on subcoxa 2, often difficult to detect; 011/1111 by half-tergite from Th. II to Abd. IV; 1 + 1, 1+ 1, 1+ 1/0, 1, 0, 1+ 1, 1 by sternite from Th. I to Abd. V (uneven on Abd. II and V).

Chaetal morphology

Ordinary chaetae well differentiated in macrochaetae and usually short mesochaetae, similar on body and appendages. Macrochaetae long, straight, smooth or extremely feebly scaled, acuminate (lateral ones) to finely sheathed and blunt (dorsal to dorso-lateral ones, Fig. 3B ). Mesochaetae smooth or minutely scaled (appearing smooth at optical resolution), relatively long, acuminate, some straight (like Di2 on tergites) and some bent (like De2, De3 on Th. II-III). S-chaetae of tergites subequal, thinner and more hyaline than ordinary chaetae, distinctly shorter than closest macrochaetae ( Fig. 2 ), 2 +ms, 2/1,1,1,2,1 by half tergite from Th. II to Abd. V. Antennal S-chaetae of various morphology, described below.

Antennae ( Fig. 4A, B )

Ant. I with 7 smooth mesochaetae. Ant. II with 11 subequal mesochaetae. Ant. III with 18 ordinary chaetae and the five S-chaetae of the Ant. III organ (2 minute, swollen and curved S-chaetae in a poorly marked cuticular fold, two subequal guard S-chaetae shorter than S1-8 of Ant. IV, the dorsal one shifted distally into Ant. IV, and one ventral mic). Ant. IV with flat, often ill-differentiated apical trilobed bulb and 8 thickened S-chaetae, S3-8 subequal, S1-2 longer and thinner; subapical organ minute. Ventrally, chaetae arrangement similar to the one illustrated by Smolis (2008) for Endonura Cassagnau, 1979 , but with an additional chaeta cp, one of the basal cp larger and similar to chaetae brs, and distal hyaline-triangular chaetae stronger.

Mouthparts ( Fig. 4 C-F)

Mandible head strong with 7 teeth, the basal one bigger but less sclerotized than others, the three distal ones in a parallel plan, the right mandible mirror of the left one. Maxilla head with 3 thick teeth and one lamella with about 20-30 cilia arranged on one side in several rows. Buccal cone short. Labrum truncated, its apical edge sinuous; labral formula 0/2,2. Labium truncated, with 4 basal, 3 distal, 4 lateral chaetae and 2 x-papilla. The distal chaetae A and C are thicker than others. Head chaetotaxy and tubercles ( Figs 2 , 5 ; Table 1)

Only 3 + 3 distinct tubercles: Oc rather large, without chaeta Ocp; De, small and bearing only the macrochaeta De1, and (L + So) as a small tubercle with 4 chaetae ( Table 1). Buttonhole present posteriorly to tubercle Oc. Chaetal group DL reduced to 3 short mes, without tubercles, that cannot be homologized. Chaeta D shifted close to chaeta F. Ventral head chaetotaxy not examined in detail.

Body chaetotaxy and tubercles ( Figs 2 , 3 , 6A ; Table 1)

Di with 2 chaetae on Th. I, 3 chaetae on Th. II-III with Di2 and Di3 short, subequal, equally distant from Di1. Abd. I-IV with 2 chaetae Di, macrochaeta De1 absent, S-chaeta of the De group on a separate micro-tubercle adjacent to DL. Abd. IV with an additional S-chaetae lo- cated among the L group of chaetae. On Abd. V tubercles Di shift laterally and fused to (De + DL + L), resulting in 1 + 1 large tubercles on the tergite. Tubercles De and DL very close on Abd. I-IV. Female with 3 + 3 antegenital, 9-14 circumgenital and 1+ 1 genital chaetae. Male with 3+ 3 antegenital, 16-17 circumgenital and 4 + 4 genital chaetae. No ventral modified chaetae on abdomen in the male. Abd. VI tergites with 6 + 6 chaetae arranged on 1 + 1 large, prominent, square and slightly divergent tubercles; each anal valve with 3 mic An, the internal one close to anal orifice often difficult to detect.

Legs ( Fig. 6B ; Table 1)

Legs with reduced chaetotaxy of tibiotarsi and femora ( Table 1). Tibiotarsus without differentiated tenent hairs, with ventral chaetae B4 and B5 subequal, acuminate, longer than inner edge of claw. Femur II-III with a very minute dorsal microchaeta. Unguis with ventro-basal granulation, no internal undulations and no inner tooth.

Variations ( Table 1)

Slight variations in chaetotaxy were observed on tibiotarsi, femora, lateral chaetae of Abd I-III, chaetae Ve of Abd. II-III and number of circumgenital chaetae. They are mentioned in Table 1.

REMARKS

Yuukianura judithae n. sp. can be separated from other species of the genus by the combination of lack of eyes, 2 chaetae on the ocular tubercle (Ocp absent), (5+5) chaetae on Th. I; (3 + S) chaetae in chaetal group DL of Th. II-III, 2 chaetae in chaetal group Di of Abd. I-IV (Di3 absent) and untoothed claw. The species exhibits also three remarkable features, rare in Neanurinae , but not documented in several other Yuukianura species : a strong reduction of tibiotarsal and to a lesser degree of femoral chaetotaxy; the absence of macrochaeta De on Abd. I-IV; and the presence of conspicuous buttonhole structures dorsally. Regarding the first character, only one species of Neanurinae , Paranura sexpunctata (Axelson, 1902) , from the tribe Paranurini , is known to present a reduction of tibiotarsal chaetae as strong as that of Y. judithae n. sp. ( Deharveng 1983a). The absence of macrochaeta De on Abd. I-IV is retrieved in Y. yasudai n. comb. and Y. tongana . Buttonhole structures have been reported in the same positions (head, Abd. I and Abd. IV) on the body of another Lobellini, Coecoloba plumleyi Deharveng, 1983 from Niugini, and of a few other Neanurinae of other tribes ( Deharveng 1983b).

Figures

FIG. 1. — Yuukianura judithae n. sp.: A, specimens on a dropping of fresh guano; B, a specimen in dorsal view, length: 2 mm.

FIG. 2. — Yuukianura judithae n. sp. in dorsal view with tubercles and chaetae figured. Pseudopores as red spots. Granules not at scale. Scale bar: 200 μm.

FIG. 3. — Yuukianura judithae n. sp.: A, tubercle L on Th. I constituted of slightly enlarged secondary granules; B, distal part of a narrowly sheathed macrochaeta (Di1 on head); C, De-DL area of Abd. I with its button-hole structure; D, De-DL area of Abd. II without button-hole structure; E, De-DL-L area of Abd. IV with its button-hole structure and 2 chaetae S; F, pseudopore on the ventral side of head near antennal basis; G, pseudopores on the sternite of Th. III. Abbreviations: see Material and methods. Scale bars: A, F, 25 μm, B, 10 μm, C-E, G, 50 μm.

FIG. 4. — Yuukianura judithae n. sp.: A, dorsal side of Ant. III-IV; B, ventral side of Ant. IV of another specimen (triangular-pointed ventral chaetae filled in black); C, mandible head; D, maxilla head; E, labrum distal edge; F, labium. Abbreviations: see Material and methods. Scale bars: 20 μm.

FIG. 5. — Yuukianura judithae n. sp.: A, chaetotaxy of lateral area on head; B, chaetotaxy of ventral side of head. Abbreviations: see Material and methods. Scale bars: 100 μm.

FIG. 6. — Yuukianura judithae n. sp.: A, ventral chaetotaxy of abdomen; areas devoid of secondary granulations (interpreted here as muscular insertions) as grey spots; pseudopores (psp) as red spots; B, chaetotaxy of tibiotarsus III. Abbreviations: gr, area with secondary granules; sm, smooth area devoid of secondary granules; other abbreviations: see Material and methods. Scale bars: 100 μm.