Entomobrya virginiae Arbea, 2021

Arbea 1, Javier I., Lopez 2, Virginia Garcia, Soria 2, Francisco Javier & Abellan 2, Pedro, 2021, Collembola from Hundidero-Gato Cave in Southern Spain, with the description of a new species of Entomobrya Rondani, 1861 (Collembola, Entomobryidae), Subterranean Biology 38, pp. 77-90 : 77

Entomobrya virginiae Arbea sp. nov. Figs 3 , 4-7 , 8-15 , Tables 1, 2

Type locality.

Sistema Hundidero-Gato, Benaoján-Montejaque, Málaga (Sierra de Grazalema Natural Park, Spain), 36°43'39"N, 5°14'19"W, 558 m a.s.l.

Type material.

Holotype female on slide, Sistema Hundidero-Gato, Benaoján-Montejaque, Málaga (Spain), dark zone, 23-VIII-2018, leg. Virginia García López; 80 paratypes, same data as holotype: 12 females, 4 males and 4 juveniles on slide (11 from twilight and 9 from dark zone) and 60 ex. in a tube with ethyl alcohol (20 from twilight and 40 from dark zone). Deposited in MNCN (holotype and paratypes in slides) and MZUN (paratypes in alcohol).

Etymology.

The name is dedicated to Virginia García López, who captured the specimens.

Description.

Body length 1.80 mm, excluding antennae (mean 16 ex., Table 1 ). Without dimorphism in colour; ground colour white or very light blue, with blue pigment on lateral body (all segments), dorsolateral segments Th II to Abd V, as two not complete stripes wider on posterior tergites, a central patch on Abd III with a truncated cone shape, other central patches on Abd I-II, and transversal bands on posterior tergites Th II-Abd III in many specimens; head with pigment on posterior lateral eyes and a dorsal V-shaped patch; on legs, pigment on distal femur and lateral tibiotarsus; antennae with pigment on Ant I tip and whole Ant II-IV (Fig. 3 ). Simplified Mc formula ( Jordana and Baquero 2005) H1-H2-H3-H4-H5/T1-T2/A1-A2/A3-A4-A5/A6-A7-A8-A9-A10 in adult females: 3-2-0-3-2/2-4/2-3/1-2-1/0-4-3-2-2.

Head. Eight eyes, GH smaller than EF. Antennae length 1.08 mm, 3.13 times the length of the head (n = 16, Table 1 ); Ant IV with apical vesicle simple (Fig. 10 ) (slightly bilobed in some specimens); relative length of Ant I/II/III/IV = 1/2.38/2.42/2.43 (Table 1 ). Labrum with 4/5,5,4 chaetae; prelabral chaetae ciliated, and labral chaetae smooth. The labium has MR*ELL ciliated Mc; R* half as long as M; the remaining labial Mc are smooth. The maxillary palp has three sublobal chaetae. The papilla E has a lateral process reaching the end of the papilla (Fig. 9 ). In the dorsal head chaetotaxy (Fig. 4 ), the H1 area has three Mc: An2, An3e1 and An3, and the H2 area with two Mc: A5 and A6 (sometimes absent or asmc in male and juvenile specimens); Mc series M with M1-M4; the H3 area without Mc S’ 0; the H4 area with S1, S3 and S4 Mc, and the H5 area with Ps2 and Ps5 Mc. There are four chaetae on the ocular well: p, q, r and s.

Thorax (Fig. 5 ). Th II has two Mc: m1 and m2i, on the T1 area; the T2 area has four Mc: m4, m4i, a5 and a5' (sometimes absent or asmc in male of juvenile specimens). Th III has complete basal chaetotaxy: a1-a7, p1-p6, m6-m7.

Abdomen (Figs 6 , 7 ). The Abd II has two Mc on area A1: a2 and a3 (sometimes absent or asmc in male or juvenile specimens) and three Mc on area A2: m3, m3ep and m3e. Abd. III has 1, 2 and 1 Mc on areas A3, A4 and A5, respectively: a1, a2, a3 (sometimes absent or asmc in male or juvenile specimens) and m3. Abd. IV with 11+11 central Mc: A3-A6, B3-B6, C1 (sometimes absent), C2a and E1 (Fig. 7 ). The trichobothria on Abd IV at the levels T2 and T4. Length ratio of Abd IV/III = 3.78 (n = 16, Table 1 ). Length of manubrium and dens 0.35 and 0.43 mm, respectively (n = 16, Table 1 ). Manubrial plate with four chaetae and two pseudopores (Fig. 13 ). Mucro with teeth similar in size, mucronal spine reaching tip of subapical tooth (Fig. 12 ).

Legs. Trochanteral organ with 15-16 smooth chaetae in V-shaped and 7-8 lateral smooth chaetae (Fig. 14 ). Tibiotarsus not subsegmented, without smooth chaetae, except for smooth terminal chaeta on legs III. Claw with four inner teeth: paired at 53-58% (one of them larger and forward), first unpaired at 70% from basis, and the last one closer than 90%; dorsal teeth at the level of lateral teeth (Fig. 15 ). Empodium lanceolate, with serrated external lamella in leg III. Tenent hair clavate, longer than claw.

Remarks.

For the identification of the species of Entomobrya we must consider a combination of colour pattern and dorsal macrochaetotaxy. It has been shown that species with the same colour pattern can have a different chaetotaxy ( Jordana and Baquero 2005). On the other hand, species with differences in color pattern can correspond with species-level genetic divergence without any obvious differences in chaetotaxy ( Katz et al. 2015b).If the macrochaetotaxy of Th II/Abd II/Abd III is considered simultaneously, twelve species of the genus share a similar simplified formula for these tergites: 2-3/2-3/1-2-1 in E. atrocincta Schött, 1896, E. maroccana Baquero & Jordana, 2008, E. melitensis Stach, 1963, E. numidica Baquero, Hamra-Kroua & Jordana, 2009, E. vergarensis Baquero, Arbea & Jordana, 2010, E. fainae Baquero & Jordana, 2018 and E. benaventi Rueda & Jordana, 2020; 2-4/2-3/1-2-1 in five species described by Baquero and Jordana (2018) from the Canary Islands, E. grimanesae , E. achuteygai , E. cf. quinquelineata , E. guayarminae and E. gazmirae ; of these twelve species, only E. melitensis , E. vergarensis , E. fainae and the females of E. atrocincta sensu Katz et al., 2015a, and E. benaventi have a colour pattern similar to the new species; but the new species is the only one with Mc a5' on Th II in females. The colour pattern of the new species could also be considered similar to that of E. multifasciata , E. atteneri and females of E. nigrocincta , which have a different macrochaetotaxy formula for the Th II (Mc a5' present in females of the new species vs. absent in others) and Abd II tergites (2-2 in E. multifasciata , 2-4 in E. atteneri , 1-2 in E. nigrocincta vs. 2-3 in the new species). Table 2 shows the differences that separate these species from the E. virginiae sp. nov.

Figures

Figure 3. Entomobrya virginiae Arbea, sp. nov. Habitus.

Figures 4 - 7. Entomobrya virginiae Arbea, sp. nov. 4 head chaetotaxy 5 Th II chaetotaxy 6 Abd II-III chaetotaxy 7 Abd IV chaetotaxy. Symbols: open circle = Mc that could be absent in male and juvenile specimens but present in females; closed circle = Mc that are always present; black chaetae-like = sensilla; black circles with a cross line = pseudopores; long chaetae = bothriotricha.

Figures 8 - 15. Entomobrya virginiae Arbea, sp. nov. 8 labrum 9 labial papilla E 10 tip of Ant IV 11 labral papillae 12 tip of dens and mucro 13 manubrial plate (open circles = Mc; gray circles = pseudopores) 14 trochanteral organ 15 claw and empodium of leg III; Scale bars: 0.02 mm (8, 12 - 15), 0.01 mm (9 - 11).