Ectonura snowdeni, Queiroz, Gabriel C. & Deharveng, Louis, 2015

Queiroz, Gabriel C. & Deharveng, Louis, 2015, New genus, new species and new record of Neanurinae (Collembola, Neanuridae) for the Neotropics, Zootaxa 4020 (1), pp. 134-152 : 136-140

Ectonura snowdeni sp.nov.

Figs 2–10 ; Tabs 1 , 2

Type material. Holotype: male (#2238 CM/ MNRJ), 25.xi.2011, Queiroz G.C. leg. Paratypes: 1 female and 1 juvenile, same data as holotype; 2 juveniles (#2351 CM/ MNRJ) 11.iv.2012, Queiroz G.C. leg. Material deposited at MNRJ in Brazil. Female (same data of holotype) and 1 juvenile (#2351 CM/ MNRJ, 11.iv.2012, Queiroz G.C. leg) deposited at MNHN in Paris, France. Type locality. Parque Nacional do Caparaó (ICMBio), Alto Caparaó municipality, Minas Gerais State, Brazil. 2500–2800 m a.s.l. Local coordinates: 20°26'7"S 41°47'54"W. Leaf litter and soil of "campos de altitude".

Description. Length 0.6–1.2mm (n=7). Colour white in ethanol. Eyes 2+2, unpigmented, their diameter twice the length of Ocm socket diameter. Habitus typical of the genus ( Fig. 2 ). Weak cryptopygy. Head and tergite tubercles weakly developed, differentiated in small bosses, with tertiary granulation. Dorso-internal tubercles of head and Th I–Abd IV not differentiated, without elementary tubercles. No reticulations. No plurichaetosis. No button-hole structures on tergites.

Dorsal chaetotaxy constituted of ordinary chaetae and S-chaetae. Ordinary chaetae differentiated in dorsal macrochaetae of similar length and morphology, rather small, with strong serrations in the distal 1/3-1/2 of their length, distally sheathed, rounded apically; lateral macrochaetae longer, less serrated and thinner apically (details of Fig. 2 ); 1+1 mesochaetae of CL and 4 mesochaetae of (L+So) on head, 3 mesochaetae of L on abd IV and 1 of L on Abd V smooth and acuminate; microchaetae present, thinner, shorter, bent, acuminate and smooth. S-chaetae thinner, slightly shorter than closest macrochaetae.

Antennae shorter than head, less than two times as long as wide at basis. Ant I with 7 chaetae, Ant II with 11 chaetae. Ant III with 18 ordinary chaetae and 5 S-chaetae of Ant III organ, guard chaetae Sgd and Sgv slightly longer and slender than S-chaetae of Ant IV. Ant IV organite as a very small rod, almost entirely burried in the integument; apical bulb slightly or undistinctly trilobed, fused to Ant IV tip. Eight subequal S-chaetae (S1–S8) on Ant IV, S4 slighlty stouter than others ( Fig. 3 ).

Buccal cone moderately elongated. Maxilla styliform, mandible thin and bidentate. Labrum rounded apically, elongated, labral formula?/?2,4. Labium with 4 basal, 3 distal and 3 lateral chaetae; 2 x-papillae visible ( Fig. 4 ).

Head chaetotaxy as in Table 1 , with 13 chaetal groups: CL, 2 An, 2 Oc, 2 Di, 2 De, 2 DL, 2 (L+So). Tubercles weakly developed, An adjacent to Oc from which it is only separated by a single row of secondary granules, and chaeta O absent; F, G and B on the edge of tubercles, D free). No tubercle Di. Detail of DL and (L+So) in Figure 4 , chaeta So5 not detected.

Tergite chaetotaxy illustrated on Fig. 2 . Tubercles Di not differentiated; De, DL and L weakly developed, visible from head to Abd VI. Chaetal group Di of Th II–III with 3 chaetae (Di1 as M and Di2-Di3 as mi). Tubercle De of Th III with 2 chaetae (De1 as M and De2 as mi) and 1 S-chaeta. Tubercles De and DL separate on Abd IV. Abd V with tubercles Di fused on the axis, separated from De; two chaetae VL(+?L) located ventrally, without tubercle. Tubercle Di of Abd V with Di1 as M, Di2 as mi and Di3 absent. Abd VI bilobed. S-chaetotaxic formula: 2+ms, 2/11111.

Tita without chaeta M and with B4–B5 not longer than other long chaetae of the Tita ( Fig. 6 ). Claw untoothed, not striated in its basal part, and devoid of secondary granulation.

Ventral chaetotaxy of Abd I–VI as in Fig. 7 . Furcal rest with 3 or 4 chaetae, devoid of mi but with a small posterior area of primary granulation ( Fig. 8 ). Female genital plate as in Fig. 9 . Male genital plate without modified chaetae ( Fig. 10 ). Postcephalic chaetotaxy summarized in Table 2 .

Etymology. Species named in honour of Edward Snowden.

Discussion. The new species Ectonura snowdeni sp. nov. is the first of the genus to be found in the Neotropical region, other described species being known from New Caledonia and South Africa, with a mention from Australia without described species ( Greenslade & Deharveng, 1990). It shares with three other species of the genus (E. koumac Deharveng & Bedos, 2002, E. monochaeta Janion, Bedos & Deharveng, 2011 and E. sylvatica Deharveng, Weiner & Najt, 1997), a reduction on the number of chaetae of the lateral tubercle of abdomen ( Table 3 ). All four species have one or two chaetae on tubercle L of Abd I–III. However, they differ by several characters listed in Table 3 . Axial tubercles Di on Th II–Abd V are developed in E. koumac and E. monochaeta, while they are only present on Abd V in E. snowdeni sp. nov.; Abd V tubercles are fused in E. koumac and E. snowdeni sp. nov., separate in E. monochaeta and E. sylvatica; from E. sylvatica, the new species differs mainly by the number of chaetae on Ant I (7 versus 8) and the labrum (rounded versus ogival) The overal combination of characters of E. snowdeni sp. nov. clearly separates it from its congeners, indicating stronger similarities with New Caledonian than South African species (see Table 3 ). Its disjunct distribution is however puzzling, and evolutionary convergence with austral Ectonura may not be completely ruled out.

*on joint tubercles Di.

Figures

FIGURES 2 – 5. Ectonura snowdeni sp. nov. 2. Dorsal chaetotaxy with detail of macrochaetae DL and L of Abd IV; 3. Dorsolateral chaetotaxy of Ant III – IV (S 8 hidden, not drawn); 4. Labium with detail of labrum; 5. Detail of right chaetal group DL and (L + So) of the head. Scale bars: 20 µm (Figs 3 – 5 and chaetae); 80 µm (Fig. 2). x—missing chaeta.

FIGURES 6 – 10. Ectonura snowdeni sp. nov. 6. Tita of leg II; 7. Ventral chaetotaxy of Abd I – VI; 8. Detail of Furcal rest; 9. Female genital plate; 10. Male genital plate. Scale bars: 20 µm (Figs 6, 8 – 10); 50 µm (Fig. 7).

Tables

TABLE 1. Dorsal Cephalic chaetotaxy of Ectonura snowdeni sp. nov.

Group of chaetae	Tubercle	Number of chaetae	Type of chaetae	Chaetae
CL	+	2+2	M* me	F G
An	+ –	1 1	M mi	B D
Oc	+	3	mi M* M	Oca Ocm Ocp
Di	–	1	M	Di1
De	+ –	1 2	M mi	De1 Di2, De2
DL	+	3	M mi	DL1, DL5 DL2
L+So	+ –	2 1 3	M* me me	So1, L4 L2, So3, So4, So6
*smooth

TABLE 2. Postcephalic chaetotaxy of Ectonura snowdeni sp. nov.

	Di	De	DL L	Scx2	Cx	Tr	Fe	Tita
Th I	1	2	1 –	0	3	6	13	18
Th II	3	2+S	2+S+ms 3	2	7	6	12	18
Th III	3	2+S	2+S 3	2	8	6	11	17