Deuteraphorura bizkaiensis Beruete, Jordana & Arbea, 2021

Beruete, Enrique, Arbea, Javier I., Baquero, Enrique & Jordana, Rafael, 2021, The family Onychiuridae (Collembola) from karst caves of the Basque biospeleologic district, with description of four new species, Zootaxa 5040 (2), pp. 151-194 : 161-165

Deuteraphorura bizkaiensis Beruete, Jordana & Arbea sp. nov.

Figs 8−17 , Tables 4 and 11

Type locality. Otxas cave , Igorre , Arratia-Nerbioi , Bizkaia / Vizcaya, 200 m asl, coordinates 43.18351509, - 2.74792462 .

Type material. Holotype female, slide MZNA714617, Otxas cave (Loc. 32), Igorre , Arratia-Nerbioi , Bizkaia / Vizcaya, 18.I.1980, C. Prieto leg. Paratypes (same informacion as holotype): 2 females (MZNA716388 and MZNA716389), 1 male (MZNA714619), and 1 juvenile (MZNA714618).

Etymology. The specific name derives from Bizkaia, the name of the territory of origin of this species.

Description. Body whitish. Length (without antennae) 0.88−1.06mm in females, 0.89 mm in males; holotype 1.06 mm. Cuticular granulation fine and uniform.

Pso formula 3,3/1,3,3/3,3,3,5,3 dorsally and 1,2/0,1,1/2 +1,1,1,1 ventrally; Abd I sternite with 1 +1 pso in anterior position, 1 + 1 pso at the base of the VT, and 1 + 1 lateral pso; Abd II–III only with the paired lateral pso; Abd IV only with the medial paired pso ( Figs 8, 9 ). Each subcoxa 1 of legs I–III with 2 pso. Neither psx nor psp could be distinguished.

Head. Antennae slightly shorter than the head; ratio length of the antenna/cephalic diagonal 0.70–0.80. Ant IV with subapical organite, and ms basolateral, relatively large, located above the first proximal row of chaetae. AIIIO composed of 5 papillae, 5 guard chaetae, 2 small internal sensilla, and 2 curved, smooth and ribbed sensory clubs; the lateral ms is located just behind the sensory organ ( Fig. 10 ). Ant I−III with 7, 14, and 16 ordinary chaetae, re- spectively. Poorly delimited antennal base, with finer granulation. PAO with 12–13 compound vesicles arranged in two rows ( Fig. 12 ). Dorsal cephalic chaeta d 0 present ( Fig. 8 ). Maxillary palp simple, with 1 basal and 2 sublobal chaetae. Labral formula 4/342 ( Fig. 11 ). Labium type AB, with 6 proximal, 4 basomedial (E, F, G, f) and 5 basolateral (b, c, d, e, e’) chaetae ( Fig. 13 ). 4 +4 postlabial chaetae along the ventral groove

Dorsal body chaetotaxy according to Table 4 and Figs 8 and 15 . Chaetae-s are well differentiated from ordinary ones, thicker, blunt, and hyaline in appearance. Th II–III with lateral ms. The axial chaetotaxy of Th II to AbdV tergites as 3,3/2–3,2–3,2–3,2,1 pairs of pointed microchaetae ( Fig. 8 ). Abd IV tergite with an axial unpaired chaeta (p 0); AbdV without axial unpaired chaetae; AbdVI with a blunt axial macrochaeta (a 0).

Ventral body chaetotaxy according to Fig. 9 . Th I–III sternites without chaetae. VT with 5 +5 distal chaetae, anterior and basal chaetae absent. Furcal vestige reduced to a finely granulated area, with 4 posterior dental microchaetae and two irregular rows of manubrial chaetae: mm row with 2 +2(1) and mp row with 2+2 chaetae, of which the outer ones are macrochaetae ( Fig. 17 ). Genital plate with 10–16 chaetae and 2 posterior microchaetae in females, and about 30 chaetae in males. Males with ventral organ formed by short and thick, sub-cylindrical chaetae: 2 on the Abd II sternite and 8 on the Abd III sternite ( Fig. 17 ). Anal valves with numerous acuminate chaetae; each lateral valve with chaetae a 0 and 2a 1; posterior valve with a 0, 2b 1, 2b 2, c 0, 2c 1 and 2c 2 ( Fig. 16 ).

Legs. Sub−coxae 1 of legs I–III with 3,4,4 chaetae, sub−coxae 2 with 0,3,3 chaetae, coxae with 2−3,8−10,11−13, trochanters with 9,9,9 and femurs with 14,14,14 chaetae, respectively. Tibiotarsi of the legs I–III with 18(9,8,1),18(9,8,1), and 17(9,7,1) chaetae, respectively ( Fig. 14 ). Claw without internal or lateral teeth. The empodial appendix reaches 60% of the inner edge of the claw, with a narrow basal lamella reaching 33% of its length ( Fig. 14 ).

Discussion. D. bizkaiensis sp. nov. share with three European cave species the presence of 3,3/1,3,3/3,3,3 pairs of pso from the head to the Abd III tergite ( D. arminiaria ( Gisin, 1961) ; D. closanica ( Gruia, 1965) ; and D. trisilvaria ( Gisin, 1962)) , whose main diagnostic differences are summarised in Table 11. The new species presents the same dorsal pso formula as D. closanica , but it differs from this species by the shape of the ventral organ of the males (four fine and long chaetae on Abd II sternite and 35–40 short, poorly differentiated chaetae, on Abd III sternite in D. closanica compared with two short thick chaetae on Abd II and eight short thick chaetae on Abd III in the new species), the shape of the empodium (with broad basal lamella in D. closanica compared with narrow in the new species), and by the number of pso in the abdominal sternites (Abd I−IV with 4,1(2),1(2),2 pairs of pso in D. closanica compared with 3,1, 1,1 in the new species). D. kosarovi ( Zonev, 1973) and D. jitkae ( Rusek, 1964) have also the same ventral pso formula on head and thorax (3/011), although for them, ventral pso on Th are unknown.

Figures

FIGURES 8−9. Deuteraphorura bizkaiensis sp. nov. 8, dorsal view; 9, ventral view. Scale: 0.2mm.

FIGURES 10−17. Deuteraphorura bizkaiensis sp. nov. 10, AntIII–IV dorsal view; 11, labrum; 12, PAO; 13, labium (labial papillae chaetae not represented); 14, tibiotarsus and claw of leg III; 15, AbdV−VI dorsal chaetotaxy; 16, AbdV−VI ventral chaetotaxy; 17, AbdII−IV sternite central chaetotaxy of a male. Scales: 0.03mm (10−14, 17), 0.1mm (15−16).