Lepidocyrtus nigrosetosus Folsom, 1927

Katz, Aron D., Taylor, Steven J., Soto-Adames, Felipe N., Addison, Aaron, Hoese, Geoffrey B., Sutton, Michael R. & Toulkeridis, Theofilos, 2016, New records and new species of springtails (Collembola: Entomobryidae, Paronellidae) from lava tubes of the Galapagos Islands (Ecuador), Subterranean Biology 17, pp. 77-120 : 84-90

Taxon classification Animalia Collembola Entomobryidae

Lepidocyrtus nigrosetosus Folsom, 1927 Figs 7, 8, 9, 10, 11, 12

Lepidocyrtus leleupi Jacquemart, 1976: 145, syn. n.

Description.

Size. Up to 2.6 mm

Color pattern. Background color white or light orange, with dark purple pigment limited to Ant. III-IV, latero-posterior margin of Th. II, lateral margin of Th. III and meso- and metathoracic coxae. Some individuals have and additional irregular purple spot on the base of the furcula, others have no pigment at all, except for the antennae. The black or dark brown look of living specimens is produced by the thick covering of black or dark brown scales (Fig. 7A).

Appendicular scales distribution. Dorsally on Ant. I, femur on middle and hind legs and ventral face of furcula. Scales absent from Ant. II-IV, fore legs, ventral tube and dorsal face of manubrium.

Head. Apical bulb on Ant. IV absent. Dorsal chaetotaxy of the head as in Figures 7B,C: Row An with 7-12 Mc; anterior Mc A0 and A2 present, relatively small but with differentiated sockets, and inserted among a group of enlarged fusiform elements field normally including only Mc A0 (Fig. 7B; fig. 2 in Jacquemart 1976), all other anterior Mc absent; posterior Mc absent, element Ps5 enlarged and fusiform; postocular bothiotrix displaced laterally and inserted behind eyes E and F. Prelabral and all labral setae smooth. Basal seta of outer maxillary palp smooth, subequal to terminal appendage; sublobal plate with 3 seta-like appendages and 1 minute, spine-like appendage on dorsal edge. Lateral appendage on labial papilla E curved anteriorly and short, not reaching tip of papilla. Labial palp with 5 smooth proximal setae. Labial triangle formula as m1M2rEL1L2, A1-5: m1 sometimes coarsely ciliate and always shorter than M2; r short, smooth and conic, sensilla-like (Fig. 8A). Anterior row of post-labial setae smooth or minutely denticulate; setae on posterior rows coarsely ciliate (Fig. 8B, C); cephalic groove with 5-6 +5-6 setae, anterior most seta smooth, setae becoming more coarsely ciliate from anterior to posterior rows; postlabial group C with 1-4 setae; modified post-labial setae 2-3, short, conic and smooth, similar to labial seta r, inserted among lateral columns.

Dorsal body chaetotaxy. Dorsal macrosetae formula 00/0233+1+6. Dorsal S-seta 11/011n3; S-microseta 10/10100. Mesothoracic hood produced, anteriorly rounded, partially or completely shadowing head. Meso- and metathoracic chaetotaxy normal, with neither Th. II polychaetosis nor Th. III reductions. Chaetotaxy of Abd. I normal, with a6 present and 11 posterior setae. Abd. II (Fig. 9A, B) with all supplementary setae fan-shaped; a2 and a6 fusiform and finely ciliate in larger individuals, normal smooth setae in smaller individuals; a3 well anterior and not reaching sensillum as; as subequal to or shorter than a3; Mc m3 and m5 present; p4, m4, and p5 smooth; elements a2p, m3e, m4i and p5p absent. Abd. III (Fig. 9C) with all supplementary setae fan-shaped; a2, a6 and am6 fan-shaped; a3 well anterior and not reaching as; as shorter than a3 and m3; Mc pm6, p6 and p7 present; mc p3, m4, p5 and S-microseta d2 present; a7 smooth or very finely denticulate, displaced laterally, not reaching am6. Abd. IV (Fig. 10) with inner Mc B4, B5, B6 and C1; all supplementary setae of both riotrichal complex fan-shaped; mc s present (Fig. 11B); bothriotricha T2 and T4 well separated; mc T3 and D1p subequal, short, displaced anteriorly, closer to T2 than T4, and not reaching Pe or Pi; lateral Mc D3, E2, E3, F1, F2, F3 present (Fig. 11A); posterior setae 10-12.

Legs. Trochanteral organ with up to 41 setae. Tenent hair spatulate on all legs. Unguis with 3-4 inner teeth, distal unpaired tooth sometimes absent; all teeth small; proximal unpaired tooth well separated from basal paired teeth. Fore and middle unguiculi relatively short, strongly truncate, with well marked inner tooth and weakly serrate posterior edge; hind unguiculus usually lanceolate or weakly truncate, rarely strongly truncate, inner tooth absent or weakly delineated; hind unguiculus always clearly longer (surpassing inner proximal unpaired ungual tooth) than fore and middle unguiculi (barely reaching inner proximal unpaired tooth).

Ventral tube. All faces covered by many finely ciliate setae; posterior face with 1+1 smooth setae on distal margin in addition to ciliate setae (Fig. 11C)

Furcula. Manubrium and dens without smooth setae. Basal tubercle of dens apically rounded, somewhat asymmetrical. Mucro with apical tooth slightly longer than basal tooth. Mucronal spine with minute basal denticles.

Remarks.

This species is characterized by the enlarged, rounded mesothoracic hood, absence of dorsal head Mc posterior to A2, smooth labial setae, absence of seta m3e on Abd. II, four inner Mc on Abd. IV, heteromorphic unguiculi (truncate on fore and middle legs, lanceolate or weakly truncate on hind leg), and a rounded but somewhat asymmetric tubercle on the dens.

As pointed out by Bernard et al. (2015) the large bodied members of the Lepidocyrtus nigrosetosus species group ( Lepidocyrtus nigrosetosus , Lepidocyrtus immaculatus Folsom, 1932, Lepidocyrtus leleupi Jacquemart, 1976 and Lepidocyrtus geayides Denis, 1931) are very similar and difficult to distinguish. Bernard et al. (2015) suggested that Lepidocyrtus leleupi , originally described from the island of Santa Cruz in the Galápagos, was likely to be a junior synonym of Lepidocyrtus nigrosetosus . Our collections of Lepidocyrtus from Santa Cruz fit the color pattern description of Lepidocyrtus leleupi and at first the specimens were identified as that species, but evaluation of other morphological characters showed the specimens to fit the range of variation reported for Lepidocyrtus nigrosetosus ( Mari Mutt 1986). To confirm these observations we studied the type series of Lepidocyrtus leleupi deposited in the Royal Belgian Institute of Natural Sciences in Brussels, Belgium.

The type series of Lepidocyrtus leleupi comprises the holotype, 11 paratypes and 4 additional specimens mounted on slides. The slide labeled holotype holds two individuals. Jacquemart (1976) did not specify which of the two individuals was the holotype, hence here we designate an individual as the holotype (arrow in Figure 12). The holotype and other members of the type series Lepidocyrtus leleupi lack mc m3e on Abd. II (Fig. 9B) and show the same range of morphological variation seen in specimens of Lepidocyrtus nigrosetosus from Puerto Rico. For this reason we consider Lepidocyrtus leleupi a junior synonym of Lepidocyrtus nigrosetosus . This makes Lepidocyrtus nigrosetosus the most geographically widespread member of the genus in the Neotropical region ( Soto-Adames and Anderson in press).

Distribution.

Galápagos (new record), Puerto Rico, Colombia, Jamaica ( Mari Mutt and Bellinger 1990), St. Thomas US Virgin Islands ( Soto-Adames 2002a, 2002b), Brazil ( Bellini and Zeppelini 2009), Nevis ( Soto-Adames and Anderson in press).

Material examined.

Ecuador, Galápagos, Santa Cruz Island: 1♀ on slide, Cueva Cascajo, wet breakdown with leaf litter on entrance floor, 9.iii.2014 (S. Taylor, J. Jacoby and M. Sutton), GLP-030, INHS Acc. 567,402; 1♀ on slide, Cueva Cañón, mossy breakdown near entrance, 15.iii.2014 (S. Taylor, J. Jacoby, S. Hagan and R. Toomey), GLP-032, INHS Acc. 567,403; 1 on slide, Cueva Aguirre, leaf litter, entrance, 10.iii.2014 (G. Hoese), GLP-046, INHS Acc. 567,404; 1♀ on slide, Cueva Chato 1, on wet soil near entrance, 8.iii.2014 (S. Taylor, J. Jacoby, S. Hagan and R. Toomey), GLP-075, INHS Acc. 567,405; 1 on slide, Cueva Chato 1, on wet soil near entrance, 8.iii.2014 (S. Taylor, J. Jacoby, S. Hagan and R. Toomey), GLP-075, CDRS; 1♂ on slide, Cueva Chato 2, leaf litter at entrance, 15.iii.2014 (S. Taylor, J. Jacoby, S. Hagan and R. Toomey), GLP-086, INHS Acc. 567,406; 1 on slide, Cueva Chato 2, leaf litter at entrance, 15.iii.2014 (S. Taylor, J. Jacoby, S. Hagan and R. Toomey), GLP-086, CDRS; 2 on slides, Cueva Chato 2, leaf litter at entrance, 15.iii.2014 (S. Taylor, J. Jacoby, S. Hagan and R. Toomey), GLP-086, INHS Acc. 567,407 & 567,408.

Lepidocyrtus leleupi Holotype, Galápagos, Santa Cruz, humus forêt humile, 200m, xi.1964; 11 paratypes with same collection information as holotype; 2 other slides with same collection locality, but 22.x.1964; 2 slides Galápagos, Santa Cruz, Station 92B, 17.ii.1974, I.G. 24.965, RBINS.