Spelaeobates (Spelaeobates) coriniensis nonveilleri Curcic , Vesovic , Vrbica & Rađa, 2023

Curcic, Srecko, Vesovic, Nikola, Vrbica, Maja, Popovic, Slađana, Radovanovic, Zeljko, Curcic, Nina B., Yamashkin, Anatoliy A., Radovic, Dejan, Yamashkin, Stanislav A., Vranic, Sofija & Rađa, Tonci, 2023, The surprising discovery of two new subterranean Leptodirini of the genus Spelaeobates Mueller, 1901 (Coleoptera, Leiodidae, Cholevinae) from Croatia after more than a century, Subterranean Biology 46, pp. 21-46 : 21

Spelaeobates (Spelaeobates) coriniensis nonveilleri Curcic, Vesovic, Vrbica & Rađa ssp. nov.

Figs 4 , 5 , 6

Type material.

Holotype: male (SSM) labeled as follows: "CROATIA, NORTHERN DALMATIA: city of Šibenik, island of Murter, settlement of Tisno, village of Jezera, Jezeranka Pit, 42 m a.s.l., 43°47'16.1"N, 15°37'25.3"E, 2.VI.2019, TR" (white label, printed) / "Holotypus Spelaeobates (Spelaeobates) coriniensis nonveilleri ssp. nov. Ćurčić, Vesović, Vrbica & Rađa det. 2022" (red label, printed).

Paratypes (10 specimens). The same data as for HT [three males and five females, IZFB]; two males (IZFB) labeled as follows: "CROATIA, NORTHERN DALMATIA: city of Šibenik, village of Banjevci, Šušnjevača Pit, 149 m a.s.l., 43°53'29.9"N, 15°38'20.8"E, 5.XI.2019, TR". All paratypes are labeled with white, printed locality labels and with red printed labels "Paratypus Spelaeobates (Spelaeobates) coriniensis nonveilleri ssp. nov. Ćurčić, Vesović, Vrbica & Rađa det. 2022" (Fig. 4 ).

Etymology.

Spelaeobates (Spelaeobates) coriniensis nonveilleri ssp. nov. is named after late Prof. Dr Guido Nonveiller, a famous Serbian and Croatian biospeleologist and an excellent connoisseur of the subterranean beetle fauna of the Balkans.

Diagnosis.

The new subspecies is morphologically closest to the nominotypic subspecies S. (S.) coriniensis coriniensis ssp. nov., with which we compared it.

Spelaeobates (S.) coriniensis nonveilleri ssp. nov. differs from S. (S.) coriniensis coriniensis ssp. nov. with respect to head shape (more elongate and narrower vs. shorter and wider), A6L/A3L (R 0.81-0.88 vs. R 0.88-1.00), shape of certain antennomeres (antennomeres I-V and IX-XI more elongate in first subpecies, whereas antennomeres VI-VIII more elongate in second subspecies), shape of pronotum (more elongate, widest before level of first third, lateral margins strongly convex anteriorly, with right hind angles vs. less elongate, widest at level of first third, lateral margins rounded anteriorly, with obtuse hind angles), PL/PW (R 1.24-1.38 vs. R 1.21-1.28), shape of process between mesocoxae on mesoventrite (sub-parallel vs. gradually narrowing apically), shape of elytra (more narrowed apically vs. less narrowed apically), shape of basal bulb in dorsal view (broadened distally vs. narrow, sub-parallel), and shape of spermatheca (less constricted medially vs. more constricted medially) (Table 1 , Figs 2 - 6 ).

Description.

Small-sized leptodirine. TL M 2.46 mm (2.42 mm in males, 2.52 mm in females), R 2.34-2.59 mm (2.34-2.52 mm in males, 2.47-2.59 mm in females).

Habitus: Body shape leptodiroid (Fig. 4A, B ), colour yellowish.

Integument: Shiny, microsculptured both dorsally and ventrally (Fig. 4C, D, F-L ). Sparsely distributed deep punctures present on head, while densely distributed, fine and separated on both pronotum and elytra (Fig. 4C, D, F, G, K, L ). Entire body dorsally covered with yellow pubescence of short length (erect on head, while recumbent on both pronotum and elytra) (Fig. 4A, B ).

Head: More than one and a half times as long as wide (HL/HW M 1.57, R 1.53-1.61), with no differences in shape between males and females, anophthalmous, occipital carina in the shape of a curved concave line (Fig. 4A, C ). Head widest in first quarter or between first quarter and third. Frons roundly impressed between antennal insertions. Labrum transverse, with a few long setae. First maxillary palpomere of similar length and width, shorter than second maxillary palpomere. Maxillary palpomeres II and III of similar length (M3L/M2L M 0.97, R 0.85-1.09). Penultimate maxillary palpomere widened apically. Last maxillary palpomere short, thin, gradually narrowing apically. Antennae inserted in basal quarter of head, slender, narrow proximally (except for first two antennomeres, which are widened), slightly widened distally, longer in males, AL M 1.86 mm, R 1.77-1.94 mm (1.86-1.94 mm in males, 1.77-1.85 mm in females), reaching end of elytra in males (Fig. 4A, B, E ). Antennomeres I and II short and wide, second of which slightly longer and narrower. Following four antennomeres more slender and slightly longer than antennomere II. Antennomere III longer than adjacent antennomeres (A3L/A2L M 1.34, R 1.23-1.45; A3L/A4L M 1.21, R 1.07-1.31). Antennomeres VII, IX, and X quite dilated distally. Antennomere VIII relatively short and narrow, shorter and narrower than anatennomeres VII, IX, X, and XI. Ultimate antennomere thin, widened sub-distally, then narrowing apically, narrower than preceding (A11W/A10W M 0.84, R 0.67-1.00). Antennomere I shortest, while antennomeres IX and XI longest. Other ratios of length of certain antennomeres: A6L/A3L M 0.86, R 0.81-0.88; A8L/A3L M 0.75, R 0.65-0.81; A11L/A8L M 2.03, R 1.77-2.25.

Prothorax: Pronotum bell-shaped, elongate, longer than wide (PL/PW M 1.30, R 1.24-1.38; M 1.29, R 1.24-1.33 in males; M 1.31, R 1.28-1.38 in females), widest between first fourth and third, wider (HW/PW M 0.91, R 0.87-0.97) and shorter than head (PL/HL M 0.91, R 0.89-0.96) (Fig. 4A, F ). Lateral margins strongly convex anteriorly, then narrowing towards posterior end, markedly concave posteriorly. Pronotal base almost straight, slightly shorter than elytral base. PB/AM M 0.89, R 0.83-0.96. Anterior margin convex medially. Lateral margins and pronotal base rimmed. Fore pronotal angles weakly expressed, rounded, obtuse. Hind pronotal angles well-expressed, right, not protruding backwards. Pronotal disc moderately convex (Fig. 4B ).

Mesothorax: Mesoventral carina very low, barely noticeable, with a few setae (Fig. 4H ). No tooth, anterior and posterior margins observed. Mesoventrite with a long, sub-parallel process between mesocoxae (Fig. 4I ). Scutellum large, sub-triangular (Fig. 4K, J ).

Metathorax: Metaventrite with no carina.

Elytra: Broad, ovoid, almost of same width in males and females (EL/EW M 1.63, R 1.55-1.76 in males; M 1.66, R 1.55-1.73 in females), markedly wider than pronotum (EW/PW M 2.28, R 2.18-2.36) (Fig. 4A, K ). Maximum width a little before middle. Lateral margins arcuate. Marginal furrows not visible from above. Shoulders barely noticeable, obtuse, covered by hind pronotal angles. Elytral disc markedly convex, steeply declining basally and gently declining apically in lateral view (Fig. 4B ). Parasutural stria absent. Elytral apex slightly attenuated, rounded. Pygidium covered by elytra.

Legs: Elongate and thin (Fig. 4A, B ). Femora broadened basally, constricted in distal half. Tibiae slender, gently curved, gradually widening distally. Each protibia with a very fine comb over entire apical third of outer margin. Fore tarsi four-segmented in both sexes, only first protarsomere in males slightly dilated (P1W/P2W M 1.20, R 1.00-1.50). Tarsal claws thin, elongate, curved, pointed apically.

Male genitalia: Aedeagus elongate, thin, small, well chitinised, almost the same as in the nominotypic subspecies (Fig. 5A, B ). Median lobe in dorsal view straight, gradually narrowing apically, with a sharp apex, barely longer than parameres (Fig. 5A ). Median lobe in lateral view quite flattened, curved basally, almost straight proximally, narrowing apically (Fig. 5B ). Basal bulb small, broadened distally and bilobed in dorsal view (Fig. 5A ), elongate and broadened basally in lateral view (Fig. 5B ). Tegmen wide from above (Fig. 5A ), in the shape of a ring around basal bulb (Fig. 5B ). Parameres elongate, thin, arcuate, sub-apically curved exteriorly, each with a moderately broadened rounded apex in dorsal view (Fig. 5A ), while straight, sub-parallel in lateral view (Fig. 5B ). Each paramera carrying four apical close-set setae, three of which longer, while one shorter (Fig. 5A ). No copulatory piece observed within inner sac (Fig. 5A, B ).

Female genitalia: Spermatheca small, chitinised, curved, somewhat constricted medially, spherical both basally and apically (Fig. 6C ). Gonostyli short, straight, moderately broadened, gradually narrowing distally, pointed apically. Each gonostylus with one long apical seta.

Male abdominal sternite IX (urite): Small, narrowing apically, sub-triangular (Fig. 6D ).

Female abdominal ventrite VIII: Small, transverse, with no anterior process, hairy, especially posteriorly (Fig. 6E ).

Intrasubspecific variability.

Some degree of intrasubspecific variability was noted in the new subspecies. It refers to the differences between the two known populations (one from the Jezeranka Pit, and the other from the Šušnjevača Pit). The following differences were observed between the individuals of the two populations mentioned: (i) head is widest in the first quarter in individuals from the population from the Jezeranka Pit vs. head is widest between the first quarter and third in specimens from the Šušnjevača Pit; (ii) antennomeres III, V, and IX, maxillary palpomere I, and elytra are more elongate in individuals from the Jezeranka Pit; (iii) antennomeres VI-VIII, X, and XI are more elongate in individuals from the Šušnjevača Pit; (iv) maxillary palpomere III is longer than maxillary palpomere II in individuals from the Šušnjevača Pit vs. maxillary palpomere III is shorter than maxillary palpomere II in individuals from the Jezeranka Pit. However, the identical shape of the aedeagus indicates that individuals from both populations belong to the same subspecies.

Sexual dimorphism.

Some degree of sexual dimorphism was noted in this new subspecies. Namely, it was found that: (i) the females are slightly longer than the males; (ii) the antennae of the males are longer than those of the females; (iii) antennomeres VIII-X are more elongate in the males than in the females; (iv) first protarsomere is broader in the males than in the females.

Type locality.

Jezeranka Pit, village of Jezera, close to the settlement of Tisno and the city of Šibenik, northern Dalmatia, Croatia.

Geographic distribution.

This new subspecies is currently known from only two localities in the vicinity of the city of Šibenik, northern Dalmatia, Croatia - the Jezeranka Pit (type locality) in the village of Jezera, near the settlement of Tisno, and the Šušnjevača Pit in the village of Banjevci. The first site is on the island (Murter), while the second is on the mainland. At the same time, this is the second official finding of a species of the genus Spelaeobates on the mainland. It is likely that the new subspecies also lives at other insular and non-insular subterranean sites in the surrounding area in northern Dalmatia.

Bionomy and habitat.

Specimens of S. (S.) coriniensis nonveilleri ssp. nov. were collected manually from the walls and floor in the innermost parts of the Jezeranka and Šušnjevača Pits, in places that were in complete darkness, with a high degree of humidity and the presence of trickling water.

Figures

Figure 2. SEM images of the morphological structures of PT male (A-G, J-L) and PT female (H, I) of Spelaeobates (Spelaeobates) coriniensis sp. nov. from the Jamurka (Rnjakusa II) Pit, village of Popovici, settlement of Gornji Karin, town of Benkovac, northern Dalmatia, Croatia A habitus, dorsal view B habitus, lateral view C head, dorsal view D microsculpture of head, dorsal view E right antenna, dorsal view F pronotum, dorsal view G microsculpture of pronotum, dorsal view H mesoventral carina, lateral view I mesoventrite, ventral view J scutellum, dorsal view K elytra, dorsal view L microsculpture of elytra, dorsal view. Scale bars: 1.0 mm (A, B); 0.5 mm (E, K); 0.2 mm (C, F, H, I); 0.1 mm (J); 0.05 mm (D, G, L).

Figure 4. SEM images of the morphological structures of PT male (A-G, J-L) and PT female (H, I) of Spelaeobates (Spelaeobates) coriniensis nonveilleri ssp. nov. from the Jezeranka Pit, village of Jezera, settlement of Tisno, island of Murter, city of Sibenik, northern Dalmatia, Croatia A habitus, dorsal view B habitus, lateral view C head, dorsal view D microsculpture of head, dorsal view E right antenna, dorsal view F pronotum, dorsal view G microsculpture of pronotum, dorsal view H mesoventral carina, lateral view I mesoventrite, ventral view J scutellum, dorsal view K elytra, dorsal view L microsculpture of elytra, dorsal view. Scale bars: 1.0 mm (A, B); 0.5 mm (E, K); 0.2 mm (C, F, H, I); 0.1 mm (J); 0.05 mm (D, G, L).

Figure 5. Bright-field images of the male genitalia of HT of Spelaeobates (Spelaeobates) coriniensis nonveilleri ssp. nov. from the Jezeranka Pit, village of Jezera, settlement of Tisno, island of Murter, city of Sibenik, northern Dalmatia, Croatia A aedeagus, dorsal view B aedeagus, lateral view. Scale bars: 0.1 mm.

Figure 6. Bright-field images of certain morphological traits of Spelaeobates (Spelaeobates) coriniensis coriniensis ssp. nov. from the Jamurka (Rnjakusa II) Pit, village of Popovici, settlement of Gornji Karin, town of Benkovac, northern Dalmatia, Croatia (A, B) and S. (S.) coriniensis nonveilleri ssp. nov. from the Jezeranka Pit, village of Jezera, settlement of Tisno, island of Murter, city of Sibenik, northern Dalmatia, Croatia (C-E) A, C PT female, spermatheca, lateral view B PT female, gonostyli, dorsal view D HT male, abdominal sternite IX (urite) E PT female, abdominal ventrite VIII. Scale bars: 0.05 mm (A, C); 0.10 mm (B, D, E).