Acanthophorella barjadzei Antić & Makarov, 2016

Antić, Dragan, Šević, Mirko, Barjadze, Shalva & Makarov, Slobodan, 2023, Review of the genus Acanthophorella Antić & Makarov, 2016 (Diplopoda, Chordeumatida, Anthroleucosomatidae), with descriptions of three new species from the Caucasus, European Journal of Taxonomy 908, pp. 39-76 : 64-70

Acanthophorella barjadzei Antić & Makarov, 2016

Figs 1A–D , 17–20 , 21B , 22

Acanthophorella barjadzei Antić & Makarov, 2016: 143 , figs 118–120.

Material examined

Topotypes GEORGIA • 2 juvs; Racha-Lechkhumi and Kvemo Svaneti Region, Ambrolauri Municipality, Racha karst massif , Velevi village , Dolabistavi Cave ; 1170 m a.s.l.; 15 Jun. 2019; H. Reip, J. Hentschel, L. Binz and E. Göbel leg.; SMNG • 2 juvs; same cave as for preceding; 25 May 2022; S. Barjadze, A. Faille and E. Maghradze; SMNS .

Additional material

GEORGIA – Racha-Lechkhumi and Kvemo Svaneti Region • 1 ♂, 1 ♀, 1 juv.; Ambrolauri Municipality, Racha karst massif , Nikortsminda village , Nikortsminda Sakinule Cave ; 1196 m a.s.l.; 24 Jul. 2022; D. Antić, E. Kiria, L. Shavadze and S. Barjadze leg.; IZB • 1 ♂, 1 ♀; same collection data as for preceding; NHMW MY10367 • 1 ♂; same collection data as for preceding; IZISU • 2 ♂♂, 6 ♀♀ (one used for SEM), 1 juv.; same cave as for preceding; 14 Jun. 2019; H. Reip, J. Hentschel, L. Binz and E. Göbel leg.; SMNG • 2 ♂♂ (one used for SEM), 1 ♀, 3 juvs; Muradi Cave ; 1500 m a.s.l.; 24 Jul. 2022; D. Antić, E. Kiria, L. Shavadze and S. Barjadze leg.; IZB • 2 ♀♀, 2 juvs; same cave as for preceding; 18 Oct. 2021; J. Grego and R. Straub leg.; IZISU.

Remarks

As more males and females are now available for A. barjadzei , we provide some additional descriptive notes here ( Figs 17–20 ). Males 19–23.5 mm long, vertical diameter of the largest ring 1.40–1.50 mm. Females 17.5–26 mm long, vertical diameter of the largest ring 1.40–1.70. Head and gnathochilarium densely setose ( Figs 17B , 18A ). Antennomere 7 with one rather bacilliform sensillum (sensillum basiconicum?) curved distad, located below sensillum trichodeum ( Fig. 18D ). Lateral to antennal sockets, a group of papilliform outgrowths present. Number of ommatidia 5–10, but mainly 5–7, in 2–3 rows, arranged in elongated triangles; ommatidia pale brownish or completely transparent ( Figs 1A, C , 17A–B, D , 18B ). In one female, the number of ommatidia is 9+10. Leg-pairs 3 and 4 in males with femoral, postfemoral and tibial distoventral pads. Leg-pair 10 in males with a rounded or subtriangular, distal, coxal protrusion, but also with a triangular, posterior, proximal, coxal protrusion. The anterior and posterior gonopods of the males from Muradi and Nikortsminda Sakinule caves almost completely agree with the gonopods of the holotype from Dolabistavi Cave. Angioxocal tufts (tf) (= hairy levers + lobes) complicated, including lobes with long and short hairlike outgrowths and spiculiform outgrowths, distally with an opening ( Fig. 19E–F ). The only difference spotted between males from Muradi and Nikortsminda Sakinule caves compared to the holotype is the presence of much shorter lateral lamellae ( Fig. 19A, F ) in males from the two mentioned caves. Leg-pair 2 in females with well-developed distomesal protrusions on coxae covered with small tubercles and setae. Vulvae ( Figs 19G–I , 20 ) with anterior part as wide as vulval length. Operculum (o) well-developed, bilobed, with 6+6 setae (5+5 lateral shorter setae and 1+1 mesal longer setae). Bursa (b) with strongly thickened anteroproximal lips on which the operculum rests. Lateral valve with eight setae, mesal valvee with nine setae. Posteriorly, bursa with wrinkled lateral lobe.

Localities and ecology

The type locality, Dolabistavi Cave, like other caves in the Racha karst massif, is formed in Cretaceous limestone. The explored length of the cave is 140 m, with a depth of 20 m ( Tatashidze et al. 2009). The cave is characterised by narrow passages without speleothems, and with a stream in the lower level, which is the source of the Khoteura River. Until this study, A. barjadzei was only known from its type locality. Antić & Makarov (2016) stated that this species probably lives also in Muradi Cave, but in the absence of adult males they left the identification to future studies. Now that we have adult males at hand, we can confirm A. barjadzei from Muradi and Nikortsminda Sakinule caves. Muradi Cave is another high altitude cave with a low and wide entrance (4× 1 m). The cave has 660 m of investigated channels and is characterised by two levels, a lower and an upper, separated by a 10 m vertical passage. From the entrance, the cave descends steeply to the lower level. The temperature in the cave is 7°C. This is one of the most famous caves in Georgia in terms of speleothems, which are very numerous and diverse in the upper level ( Asanidze et al. 2017). The most interesting and unique among them are certainly the pool speleothems (https://www.youtube.com/watch?v=z2TfqQEUxMA). Nikortsminda Sakinule is a 100 m long and 15 m deep cave that is poor in speleothems but well known for its ice formations and low temperature ( Tatashidze et al. 2009). From the huge entrance the cave slopes steeply downwards. This part of the cave is mainly characterised by lined boulders and stones. From the lower part of the cave, a steep ascent leads to the second part, which is much wetter and with a mostly clay substrate.

In Dolabistavi Cave, specimens of A. barjadzei were found in the dark parts, crawling around on the wet rocks. In Muradi Cave, specimens were found in the lower part of the cave (we did not explore the upper part), walking and probably feeding on wet dead wood. In Nikortsminda Sakinule Cave, specimens were found between near the entrance and the second, completely dark part of the cave. All animals were found in the left part of the cave, which is almost in complete darkness and characterised by very wet and cold stones. The specimens mainly walked on the stones covered with green algae or on dead wood or deeper on clay. Some were feeding on algae, as the green colour was clearly visible in the gut.

Besides A. barjadzei , another troglobiotic millipede inhabiting all three caves is the hydrophilous Leucogeorgia longipes Verhoeff, 1930 ( Antić & Reip 2020 for Dolabistavi; unpublished for Muradi and Nikortsminda Sakinule). One more interesting, stygobiotic species from Dolabistavi Cave is the recently described, Hausdorfenia pseudohauffenia Grego & Mumladze, 2020 ( Gastropoda) ( Grego et al. 2020). For additional taxa known from Dolabistavi Cave see Barjadze et al. (2015). In Nikortsminda Sakinule Cave, five mite and one springtail species have been recorded so far ( Barjadze et al. 2015). During the expedition, we registered additional four troglobionts from the genera Neobisium ( Pseudoscorpiones ), Nemaspela Šilhavý, 1966 ( Opiliones ), Inotrechus ( Coleoptera ) and Pseudosinella Schäffer, 1897 ( Collembola) (unpubl.). In Muradi Cave, besides two troglobiotic millipede species, we registered two troglophiles, viz., Micropterna clavata and Stenophylax permistus (both Trichoptera ) (unpubl.).

Based on the ecology, the unpigmented body and the unpigmented or pale brownish and reduced number of ommatidia, A. barjadzei can be considered as a troglobiont. Furthermore, this species is characterised by a more robust and larger body (cave gigantism), compared to its congeners. With a length of up to 26 mm, A. barjadzei , together with the members of the troglobiotic genus Heterocaucaseuma Antić & Makarov, 2016 , is the largest chordeumatidan in the Caucasus.

Distribution

A Georgian endemic known from three high-altitude caves (ca 1200–1500 m a.s.l.) in the Racha karst massif ( Fig. 22 , cyan circles).

Figures

Fig. 1. Troglobiotic members of the genus Acanthophorella Antić & Makarov, 2016 in situ. A–B. Acanthophorella barjadzei Antić & Makarov, 2016, ♂ from Nikortsminda Sakinule Cave. C–D. Acanthophorella barjadzei Antić & Makarov, 2016, ♂ from Muradi Cave. E–F. Acanthophorella devi Antić sp. nov., types, ♂♂. G–H. Acanthophorella valerii Antić sp. nov., holotype, ♂ (NHMW MY10366). Photos by Dragan Antić.

Fig. 17. Acanthophorella barjadzei Antić & Makarov, 2016. A. ♂ from Nikortsminda Sakinule Cave, habitus, lateral view (NHMW MY10367). B. ♀ from Nikortsminda Sakinule Cave, head, lateral view (NHMW MY10367). C. ♂ from Muradi Cave, midbody rings, dorsal view (IZB). D. Subadult ♀ from Muradi Cave, head, lateral view (IZISU). E. ♂ from Muradi Cave, midbody rings, lateral view (IZB). Scale bars: A–C, E = 1 mm; D = 0.5 mm.

Fig. 18. Acanthophorella barjadzei Antić & Makarov, 2016, ♂ from Muradi Cave (IZB). A. Head, anterior view. B. Left field with ommatidia, anterolateral view. C. Right antenna, dorsal view. D. Right antennomere 7, dorsal view, arrow indicates bacilliform sensillum. E. Ring 14, dorsal view. F. Ring 14, dorsolateral view. G. Rings 14 and 15, anterior view. Scale bars: A, C, E = 0.2 mm; B, D = 0.05 mm; F–G = 0.5 mm.

Fig. 19. Acanthophorella barjadzei Antić & Makarov, 2016. A–F. ♂ from Muradi Cave (IZB). G–I. ♀ from Nikortsminda Sakinule Cave (SMNG). A. Anterior gonopods, anterodistal view. B. Anterior gonopods, anterolaterodistal view.C. Anterior gonopods, lateral view.D. Anterior gonopods, distal view. E. Anterior gonopods, posterior view. F. Anterior gonopods, right tuft, posterior view. G. Left vulva, distal view. H. Left vulva, anterodistal view. I. Left vulva, lateral view. Abbreviations: a = angiocoxite; ap = anterior process; b = bursa; cv = coxal vesicle; ll = lateral lamella; mp = medial part; o = operculum; s = sternum; sa = synangiocoxal base; sl = sternal lamella; tf = angiocoxal tuft. Scale bars = 0.1 mm.

Fig. 20. Acanthophorella barjadzei Antić & Makarov, 2016, ♀ from Nikortsminda Sakinule Cave (SMNG). A. Left vulva, distal view. B. Left vulva, anterior view. C. Right vulva, lateral view. Drawings by MŠ. Abbreviations: b = bursa; o = operculum. Scale bar = 0.2 mm.

Fig. 21. Anterior gonopods in the genera Acanthophorella Antić & Makarov, 2016 and PseudoflagellophorellaAntić & Makarov, 2016, anterior views. A. A. auritaAntić sp. nov. B. A. barjadzei Antić & Makarov, 2016. C. A. chegemi Antić & Makarov, 2016. D. A. devi Antić sp. nov. E. A. irystoni Antić & Makarov, 2016. F. A. valerii Antić sp. nov. G. P. eskovi Antić & Makarov, 2016. H. P. mirabilis Antić & Makarov, 2016. I. P. papilioformis Antić & Makarov, 2016. B–C, E, G–I after Antić & Makarov (2016). Scale bar = 0.2 mm.

Fig. 22. Distribution of the genus Acanthophorella Antić & Makarov, 2016.