Euxinopetalum dobatorum Hoffman, 1973

Antić, Dragan, Aleksić, Tamara, Milovanović, Jelena & Elverici, Mert, 2024, Rediscovery of Euxinopetalum dobatorum Hoffman, 1973 (Diplopoda, Callipodida, Schizopetalidae) in Turkey, Caucasiana 3, pp. 223-234 : 223-234

Euxinopetalum dobatorum Hoffman, 1973

Figs 1 , 2 , 3 , 4 , 5

Euxinopetalum dobatorum Hoffman, 1973: 86, figs 1–4; Enghoff 2006: 188; Stoev et al. 2008: 32.

Material examined.

TURKEY • 3 males, 1 female; Zonguldak Province, Ereğli District, Herakles Cave (= “ Höhle 2 bei Ereğli ”, = “ Cave Nr. 2, Indere, 2 km northwest of Ereğli ”), part of Cehennem Ağzı Caves; N 41.291725, E 31.411989; 35 m a. s. l.; 18 Aug. 2020; leg. M. Elverici; ABBM (1 male, 1 female), IZB (1 male), NHMW MY 10517 (1 male) .

Diagnosis.

As for the genus.

Descriptive notes (based on new samples).

Living animals brownish-grey (Fig. 1 A, B ). Ommatidia black (Fig. 2 C ). Female with a pair of white anterodorsal spots on segment 3 (Fig. 1 A, B ). Body with 36 segments (including telson) in all four specimens (Fig. 2 A ). Males 13–13.5 mm long, vertical diameter of the highest segment 1 mm. Female 15 mm long, vertical diameter of the highest segment 1.5 mm. Head setose, without modifications, with 33–35 ommatidia arranged in subtriangular field; labrum and gnathochilarium normal (Fig. 2 C – G ). Antennae 2.2 mm long (in male 13.5 mm long); antennomere 5 with distodorsal area of sensilla basiconica; antennomere 6 with distal oreola of sensilla basiconica in several rows. Metazonae with ca. 16 + 16 longitudinal crests (Fig. 2 F, H ). Ozopores opening on anterior ends between the 4 th and 5 th crests (Fig. 2 F, H ). Paraprocts subdivided, with 2 + 2 setae; hypoproct single with 4 setae (Fig. 2 B ). Leg pairs 1–3 in males, and 1 and 3 in females with tarsal combs. In males leg pairs 3–7 and 9–12 with visible coxal vesicles; coxa 2 with gonopore located on posterior side; leg pairs 4–7 without tarsal claws (one leg 4 with very reduced claw), tarsi with modified ventral setae in distal two-thirds (Fig. 3 A – D ); all podomeres with very long and densely setose ventral setae. In female leg pairs 3–12 with visible coxal vesicles; leg pair 2 vestigial, triangular with coxa and one podomere covered by long setae (Fig. 3 E, F ).

Gonopods (Figs 4 and 5 ). Parallel to each other; partly protruding outside the segment 7. Without sternum. Coxa (c) well developed. Coxal processes (cp) sigmoid, curved anteriad, twice as short as telopodites (t) with a few long proximomesal setae. Telopodite columnar, relatively simple, distally bifurcated. Lateral branch higher, with digitiform rounded lobe (dl) with five setae on mesal surface and minute setulae on outer surface, and posteromesal acuminate or bifurcated lamella (l). Setulae also present in outer central part of telopodite. Mesal branch with three processes: solenomere (s) as the most lateral one, medial process (mp) parallel to solenomere, and trifurcated, partly lamellar, mesal process (tp). Vulvae (Figs 2 G , 3 E ) extruded very long, tubular. For a detailed description of the taxоn, see Hoffman (1973: 85).

Habitat and distribution.

This is apparently a troglophilic taxon. So far, it is known from two caves in the Zonguldak Province on the western Black Sea coast in Turkey. The original description contains no additional data for the two given localities. The type locality, Heracles Cave (see also discussion), is part of three closely located tourist caves or caverns with archeological significance, referred to as “ Hell’s Mouth Caves ” in direct translation from Turkish (= Cehennemağzı Mağaraları). These caves are linked to Greek mythology, in particular with the story of Hercules (Heracles) and his descent into the Underworld. According to mythology, this is where Hercules entered Hades to capture Cerberus, the three-headed guard dog of the Underworld, as part of his Twelfth Labour ( Demirtaş and Pınarcık 2016). The area is also associated with the ancient city of Herakleia Pontica, which was named after Hercules (the Turkish name Ereğli is a derivative of Herakleia). The caves hold historical and mythological significance and are visited by many people daily ( Türker and Yaşar 2019). The complex consists of three caves: the Church Cave, Heracles Cave, and Ayazma Cave. They are sometimes referred to as the Acheron Caves, after the ancient name of the nearby river, further connecting the site to mythological depictions of the Underworld.

The main gallery of this tourist cave is severely transformed and illuminated. The new specimens were discovered in a fossil, narrow lateral passage that falls under the complete provision of the dark zone (Fig. 1 C ). The environment is characterized by an extremely low abundance of organisms, as is usual in an oligotrophic subterranean ecosystem, with roots occasionally penetrating the ceilings, reaching from the epigean ecosystem. The full list of taxa found in the Heracles Cave can be seen in Strouhal (1971: 379, 380) under the name “ Höhle 2 ”.

Remarks.

The examination of recently collected specimens, consisting of three males and one female, generally agrees with the description of Hoffman (1973), with some exceptions. Hoffman (1973) states that the male and female are about 15 mm and 23 mm long, respectively, and have 38 segments each. The individuals from our sample are smaller, the males are 13–13.5 mm long, while the female is 15.5 mm long and they have two segments less, i. e. 36. As for the second pair of legs of the female, Hoffman (1973) states that these structures are only present in the form of " minute biramous vestiges ". In the female we examined, the second pair of legs is indeed reduced and closely resembles Hoffman's (1973: 88, fig. 3) drawing, but with a clearly visible podomere and long setae on both parts. For this reason, it cannot be ruled out that Hoffman's female belongs to a different species. Finally, according to Hoffman (1973: 87, fig. 2), the mesal branch of the telopodite has four processes (labeled by him as 3, 4, 5, 6). However, what he described as process 6 is actually part of process 3.

To avoid confusion, the telopodite is attached to the posterior side of the coxa. Hoffman (1973: 85) incorrectly stated that “ … telopodite attached on oral side of coxa … ”, but on the next page he correctly writes ( Hoffman 1973: 86) “ Telopodite attached on posterior side of coxa … ”

Figures

Figure 1. Euxinopetalum dobatorum Hoffman, 1973. A, B: female in situ (ABBM); C: cave plan with collection point.

Figure 2. Euxinopetalum dobatorum Hoffman, 1973 habitus. A: male (ABBM), habitus, lateral view; B: female (ABBM), telson, ventral view; C: male (ABBM), anterior part of body, lateral view; D: male (IZB), anterior part of body, dorsal view; E: male (IZB), head, anterior view; F: male (NHMW MY 10517), midbody segments, dorsolateral view; G: female (ABBM), anterior part of body, anterior and ventral view; H: female (ABBM), body segments 22–25, dorsal view. White arrows indicate ozopores. Scale bars = 1 mm (A), 0.5 mm (B – H).

Figure 3. Euxinopetalum dobatorum Hoffman, 1973 male (IZB) and female (ABBM). A – D: left distal podomeres of male legs 4–7, respectively, anterior views; E: female leg pair 2 and vulvae, anterior view; F: female leg pair 2, anterior view. Scale bars = 1 mm (E), 0.2 mm (A – D, F).

Figure 4. Euxinopetalum dobatorum Hoffman, 1973 male (IZB), gonopods. A, B: anterior view; C, D: posterior view. Scale bars = 0.3 mm.

Figure 5. Euxinopetalum dobatorum Hoffman, 1973 male (IZB), gonopods. A: anterior view; B: distal part of right telopodite, anterior view; C: posterodistal view; D: distal part of left telopodite, posterodistal view; E: distal part of right telopodite, anterodistal view; F: distal part of left telopodite, anterior view; G: right telopodite and distal part of right coxal process, mesal view; H: lateral view. Abbreviations = c-coxa; cp-coxal process; dl-digitiform rounded lobe; l-lamella; mp-medial process; s-solenomere; t-telopodite; tp-trifurcated mesal process. Scale bars = 0.1 (A, C), 0.05 mm (B, D, E – H).