Bilobella mahunkai, Dányi, László, 2010

Dányi, László, 2010, Review of the genus Bilobella Caroli, 1912 in the Balkan Peninsula with description of a new species (Collembola: Neanuridae), Zootaxa 2605, pp. 27-44 : 29-36

publication ID	https://doi.org/ 10.5281/zenodo.197682
DOI	https://doi.org/10.5281/zenodo.5615425
persistent identifier	https://treatment.plazi.org/id/03E8878C-3C0D-7359-D89D-F8D9FD17FDCD
treatment provided by	Plazi
scientific name	Bilobella mahunkai
status	sp. nov.

Treatment

Bilobella mahunkai sp. nov.

Figs 1–37 View FIGURE 1 View FIGURE 2 View FIGURES 3 – 6 View FIGURES 7 – 15 View FIGURES 16 – 19 View FIGURES 20 – 27 View FIGURES 28 – 33 View FIGURES 34 – 38 , Tab. 1–2 View TABLE 1

Diagnosis. Dorsal tubercles extremely developed. Colour sulphureous yellow. Buccal cone elongated. Labral chaetotaxy 4/2, 4. Maxilla without apical tooth. Ant. I with 9, ant. II with 11 chaetae. Absence of chaetae D and O on head. Tubercle (Di+De) of head with 4 chaetae. Tubercle De of th. I with 3 chaetae, tubercle De of th. II–III with 4 chaetae. Integumental granulation arranged into separated fields on papillae. Tubercle L of abd. IV with 8 chaetae. Tubercle (Di+De+Dl) of abd. V with 10 chaetae. Claws without teeth.

Type material. Holotype: adult female in alcohol (vial Nr.: coll–619): Montenegro 2008/19, Lovćen Mts, 2 km from the Lovćen peak towards Njeguši, 1377 m [beech forest] – N42°23.994' E18°49.882' leg. L. Dányi, Z. Fehér, J. Kontschán & D. Murányi, 8.x.2008. Paratypes: 1 male in alcohol (vial Nr.: coll–651) and on a slide (collpr–488 (left antenna): the same data as holotype; 1 female on slides (Nr.: collpr–401 (body), collpr– 439 (labial cone), collpr–440 (head), collpr–449 (left legs)): same data as holotype.

Other material. 1 female in alcohol (vial Nr.: coll–652; coated with gold–palladium for scanning microscopy): same data as holotype.

Etymology. The new species is named in honour of the renowned acarologist Professor Sándor Mahunka (Systematic Zoology Research Group of the Hungarian Academy of Sciences (HAS), and Department of Zoology, HNHM), colleague and friend, who initiated my work on springtails.

Description. Habitus similar to Bilobella digitata with dorsal tubercles well developed, prolonged and of finger-shape ( Figs 2–3 View FIGURE 2 View FIGURES 3 – 6 ).

Body length (without antennae) 2.75–5.2 mm (holotype 5.2 mm). Tertiary granulation well developed, with reticular pattern formed by the grouping’s of granules into separated fields on papillae ( Figs 28–35 View FIGURES 28 – 33 View FIGURES 34 – 38 ). Reticulation on ventral side of body present.

Colour of the body sulphureous yellow in living specimens ( Fig. 2 View FIGURE 2 ), but fading to white in alcohol. 2+2 medium, unpigmented eyes ( Figs 3 View FIGURES 3 – 6 , 28 View FIGURES 28 – 33 ).

Dorsal ordinary chaetae: macrochaetae Ml thickened, narrowly sheathed, apically arc-like ( Figs 3 View FIGURES 3 – 6 , 29–35 View FIGURES 28 – 33 View FIGURES 34 – 38 ) and distinctly serrated ( Figs 36–37 View FIGURES 34 – 38 ); macrochaetae Mc with similar morphology, mesochaetae thin and pointed.

Head. Buccal cone distinctly elongated. Labrum with ventral sclerifications as in Fig. 7 View FIGURES 7 – 15 . Labrum chaetotaxy 4/2, 4 ( Fig. 7 View FIGURES 7 – 15 ), prelabral chaetae very tiny, two medial ones in a forward position. Chaetotaxy of labium as in Fig. 6 View FIGURES 3 – 6 and Tab. 1 View TABLE 1 . Maxilla styliform ( Fig. 8 View FIGURES 7 – 15 ) with two coherent lamellae. Mandible thin with 2 basal and one three-branched apical teeth ( Figs 8–9 View FIGURES 7 – 15 ). Ant. I and II with 9 and 11 chaetae respectively ( Figs 10–11 View FIGURES 7 – 15 ). Ant. III and IV fused dorsally. Dorsal and ventral chaetotaxy of ant. III–IV as in Figs 14–15 View FIGURES 7 – 15 , respectively. Apical vesicle distinct, trilobed. Ant. III or. as in Figs 13 and 15 View FIGURES 7 – 15 , subapical organite of antenna IV as in Fig. 14 View FIGURES 7 – 15 . Ant. IV with 8 moderately thickened S–chaetae, of which S3, S4, S7 and S8 distinctly longer than other sensilla ( Figs 14–15 View FIGURES 7 – 15 ). S1 and S2 weaker. Chaetotaxy of head as in Figs 3–4, 5 View FIGURES 3 – 6 and Tab. 1 View TABLE 1 . Chaetae D and O absent.

Thorax, abdomen, legs. Dorsal chaetotaxy of thorax and abdomen as in Figs 3 View FIGURES 3 – 6 , 16 View FIGURES 16 – 19 , 20 View FIGURES 20 – 27 , 29–35 View FIGURES 28 – 33 View FIGURES 34 – 38 and Tab. 2. Th. I: De with 2Mc, 1Ml; Dl with Ml. Th. II and III: Di with 1Mc, 1Ml; De with 2Mc, 1Ml, 1S; Dl th. II with 2Mc, 1Ml, 1S, 1ms; Dl th. III with 2Mc, 1Ml, 1S; L with 2Mc, 1Ml. Abd. I–III: Di with 1Mc, 1Ml; De with 1Mc, 1Ml, 1S; Dl with 1Mc, 1Ml; L abd. I with 2Mc, 1Ml; L abd. II with 3me, 1Mc, 1Ml; L abd. III with 4(3– 5, in holotype 3–4)me, 1Mc, 1Ml. Abd. IV: Di with 1Mc, 1Ml; (De+Dl) with 2Mc, 2Ml, 1S; L with 3me, 4Mc, 1Ml. Abd. V: (Di+De+Dl+L) with 6Mc, 3Ml, 1S. Abd. VI: (Di+De+Dl+L) with 4Mc, 3Ml.

Ventral chaetotaxy of thorax as in Fig. 20 View FIGURES 20 – 27 and Tab. 2, of abdomen as in Fig. 16 View FIGURES 16 – 19 and Tab. 2. VT with 4– 5+4–5 chaetae. Furca rudimentary, with 4–6 (in holotype 4) mesochaetae, without microchaetae ( Figs 16, 18 View FIGURES 16 – 19 ). Cryptopygy present ( Figs 3 View FIGURES 3 – 6 , 34 View FIGURES 34 – 38 ). Chaetotaxy of legs as in Figs 20–22, 24–27 View FIGURES 20 – 27 and Tab. 2. M chaeta present. Claw without tooth ( Figs 21–27 View FIGURES 20 – 27 ). Posterior surface of each trochanter with one modified chaeta as in Figs 22, 25 and 27 View FIGURES 20 – 27 . Anterior and posterior sides of femur I–III with one modified chaeta as in Figs 21–22, 24–27 View FIGURES 20 – 27 .

Mc C, E Number of other cephalic chaetae: Vi, 6; Ve, 9; labrum, 4/2, 4; labium, 10, 0x; ant. I, 9; ant. II, 11; ant. III, 13+5s; ant. IV, 8S+i+or+12mou.

Terga Legs

Di De Dl L Scx2 Cx Tr Fe T th. I – 3 1 – 0 3(4) 6 13 19 th. II 2 3+s 3+s+ms 3 2 7 6 12 19 th. III 2 3+s 3+ s 3 2 8 6 11 18

Sterna

Abd. I 2 2+ s 2 3 VT: 4–5

Abd. II 2 2+ s 2 5 (4) Ve: 3–4 Ve1: 3–4

Abd. III 2 2+ s 2 6 (5–7) Ve: 5–8 Fu: 4–6, 0 mi Abd. IV 2 4+s 8 Ve: 5 + 1 Vl: 5 Abd. V 9 +s Ag: 4–5 Vl: 3–4 Abd. VI 7 Ve: 13–14 An: 2 mi Variability and aberrations. Ve of abd. II weakly reticulated in female paratype ( Fig. 16 View FIGURES 16 – 19 ), but missing in other specimens.

The following features observed in some of the specimens are considered as aberrations: Holotype Di tubercle on th. II. asymmetrically with one additional Mc on the right side, right coxa I with an extra (4th) chaeta asymmetrically. Female paratype with only one G chaeta in medial position on clypeal tubercle ( Fig. 4 View FIGURES 3 – 6 ). Male paratype with only 4 (instead of 5) chaetae on one side on L tubercles of abd. II. Tubercles L on abd. III with asymmetrical chaetal numbers in two specimens (5+ 6 in holotype, 6+ 7 in male paratype). Female paratype with an extra (5th) chaeta on VT asymmetrically.

Ecology. The specimens were collected in the thick layer of leaf litter in a beech forest on limestone, at 1377 m above sea level. All four specimens were aggregated in one group on the surface of only one leaf, while carefully searching an area of about 50 m 2 did not result in finding any further specimens.

Three of the four specimens were infected by Nematoda specimens ( Fig. 38 View FIGURES 34 – 38 ). There is one on the holotype’s (De+Dl) tubercle on abd. VI and one on lateral side of the head on both other females. The nematodes in question are larvae and probably belong to the order Rhabditida (István Andrássy pers. comm.). These larvae are merely phoretic, they do not parasite hosts otherwise but use them for changing places (István Andrássy pers. comm.). Nematode phoresis on springtails seems to be not a rare phenomenon (e.g. Frans Janssens in litt.), although there are only few cases documented ( Miles 1971, 1976, 1986).

Discussion. Bilobella mahunkai sp. nov. is unique in the genus Bilobella because of the presence of three chaetae on tubercle De of thoracal tergum I (in each other species: 2). Among the Bilobella species with 4 chaetae on tubercle De of thoracal terga II, there are only three other ones bearing finger-like elongated posterior tubercles: B. coiffaiti , B. digitata and B. zekoi . B. zekoi differs from the new species in colour (red in B. zekoi and yellow in B. mahunkai ) and in abdominal chaetotaxy ( B. zekoi with about twice the number of chaetae than B. mahunkai on L tubercle of abd. I–IV and on (Di+De+Dl) tubercle of abd. V–VI). The new species is similar to B. coiffaiti in the reticulation formed by the integumental granulation’s grouping that is missing in B. digitata and it is similar to B. digitata in simple cuticular papillae which are more complex (conifer cone-like) in B. coiffaiti ( Cassagnau 1968: Figs 7 View FIGURES 7 – 15 A, 7C). B. mahunkai sp. nov. differs from both B. coiffaiti and B. digitata in the chaetotaxy of the tubercle L on abd. IV (8 chaetae in B. mahunkai , 5 and 6 in B. coiffaiti and B. digitata respectively) and in the chaetotaxy of tubercle (Di+De+Dl) of abd. V (10 chaetae in B. mahunkai and 8 in B. coiffaiti and B. digitata ).