Limax macedonicus macedonicus

Limax macedonicus macedonicus View in CoL P. Hesse, 1928 (reinst. stat.)

( Figs. 4 A, B View FIGURE 4 ; 5 A View FIGURE 5 ; 7 C, F View FIGURE 7 )

Limax macedonicus View in CoL P. Hesse, 1928 — Hesse, 1928: 10–12, Pl. 2, Fig. 10. [Original description]; Wagner, 1934: 53, Fig. 3 View FIGURE 3 . [Misidentification in literature of L. graecus View in CoL ]; Jaeckel, Klemm & Meise, 1957: 160; Urbanski & Wiktor, 1968: 58–60, Fig. 4 View FIGURE 4 . [Misidentification in literature of L. graecus View in CoL ]; Damjanov & Likharev, 1975: 304–306, Fig. 235. [Misidentification in literature of L. graecus View in CoL ];

Limax ( Limax) graecus, Simroth, 1889 View in CoL — Wiktor, 1996: 77–78.

Material examined. North Macedonia • Jakupica Mountains (=Mokra Planina), Karadzhica ridge, eastern slopes of Solunska Glava, in open habitat, rocky alpine meadow, on limestone, 41.7136°N 021.3956E °, 2279 m, leg. I. Dedov, 11.07.2011. BNM 063258–063260, BNM 064074–064081/ 11 specimens. ( Fig. 2A View FIGURE 2 ); • Jakupica Mountains (=Mokra Planina Mountains ), Karadzhica Ridge, Marina Rupa area, a sinkhole/dolina, situated little north of Čeples peak and little southwest of Kantarica peak, in open habitat, rocky alpine meadow on limestone, 41.6781ºN 021.3999ºE, 2128 m, leg. I. Dedov, 10.07.2017, IBER-BAS, Coll.No.10765/ 1 specimen; 1 more specimen observed ( Fig. 2B View FIGURE 2 ); • Jakupica Mountains (=Mokra Planina Mountains ), Karadzhica Ridge, Marina Rupa area, a sinkhole/dolina, situated little north of Čeples peak and little southwest of Kantarica peak, in open habitat, rocky alpine meadow on limestone, 41.6776ºN 021.3949ºE, 2217 m, leg. I. Dedov, 10.07.2017, IBER-BAS, Coll.No.10767/ 1 specimen; 2 more specimens observed ( Fig. 2C View FIGURE 2 ).

Diagnosis

Limax macedonicus macedonicus is a small sized species ( 55–80 mm) in comparison to other species of the genus living in Macedonia and elsewhere on the Balkans. Limax macedonicus macedonicu s is almost totally deep black invariably all over the body including the keel, which is not the case with any of the other accepted species of Limax with penial appendage, and a striking and distinctive character. Only the sides of the neck are cream-whitishyellowish, underpart of the free mantle flap, and the center field of the sole. The lateral sole fields are always dark-grayish-black, even in relatively small juveniles. The penis is c. as long as the body. The penis ends with a bent blind penial appendage, which is strongly coiled, massively thickening towards the insertion of vas deferens ( VD) and penis retractor muscle ( PR); VD and PR are inserting at the (more or less) same spot with no or almost no space between them. The duct of the bursa copulatrix ( BCD) is attached close to the atrium. The subspecies L. macedonicus macedonicus is only known from the type locality.

Morphology

Body measurements are presented in Table 1. All measurements are taken from specimens preserved in ethanol 75% + 3% glycerol (N2), in millimeters. No measurements of live specimens.

Limax macedonicus macedonicus , unlike most species of the genus, are of an astonishingly uniform deep black color ( Fig. 4 A, B View FIGURE 4 ). This black is covering any visible parts of resting or crawling specimens in any of the developmental stages known up to now. Even ommatophores and tentacles are entirely deep black as well as the skin between wrinkle rows and in deep folds. No other pigmentation or markings are visible. Cream-white are only the lateral sides of the neck, main underpart of the free mantle flap and the center field of the sole. The sole pigmentation fades partly after fixation in ethanol. In preserved specimens the black pigmentation is unusually dense and not to be compared with dark specimens of any of the known species of Limax species with penial appendage, e.g. Limax cephalonicus Simroth, 1886 and L. graecus ( Fig. 4 C View FIGURE 4 ). In these species, even in very dark (“black”) pigmented specimens, there is always a hue of brown, ocher, etc., often a lightening to a very dark gray (personal observations). The only species known to us of this general dark black pigmentation is Limax wohlberedti Simroth, 1900 , and L. cinereoniger but those species have no penial appendage.

Mantle of L. macedonicus macedonicus is showing the typical “fingerprint” structures of Limax spp. when alive ( Fig. 4 A, B View FIGURE 4 ). These are lost in preserved specimens.

As already described by P. Hesse (1928), the wrinkle rows in L. macedonicus are fine and there are more wrinkles than in other species of the genus ( Table 2). In fact, all wrinkles are slightly carinate and shallow in live specimens. Live animals are almost smooth at first sight, and especially when disturbed and secreting more slime. The thin and very fine sculptured skin is a distinctive character for both subspecies. The keel is totally black, very short and not especially high. Among the posterior dorsal wrinkle rows, it remains almost invisible without magnification ( Fig. 4 A, B View FIGURE 4 ). P. Hesse (1928) mentioned the end of the dorsum to be characteristic and distinctive: the species exteriorly is distinguished by the high, suddenly steep falling down end of tail. In our opinion it is an erroneous observation, because P. Hesse had only preserved specimens at hand which were killed in ethanol and therefore contracted. We observed that the shape of the dorsum end varies when the specimens are fully stretched and/or crawling or the specimens are contracted (for example in rest position).

Shell

Shell is typical for the genus—strongly flattened, thin, asymmetrical (see Wiktor 1983). Embryonic part shifted posteriorly and to the left of longitudinal axis, more clearly defined in L. macedonicus macedonicus , than in L. macedonicus leucopus (see Wiktor 1983) ( Fig. 5 A View FIGURE 5 ). Size: c. 10 mm.

Anatomy

The anatomy of L. macedonicus macedonicus follows the anatomy of L. graecus ( Fig. 6 View FIGURE 6 ): relatively long penis comparable to body length with bent blind penial appendage. The main differences that distinguish the alpine taxa from the other Limax species with penial appendage are: gray-black pigmented upper penis part (towards the penial appendage), including the penial appendage itself; the duct of the bursa copulatrix is attached close to the atrium, contrary to L. graecus in which the duct of the bursa copulatrix is attached to the free oviduct; VD and PR are inserting at the same spot with almost no space between, contrary to L. graecus in which there are distance between VD and PR.

The main parts of L. graecus type anatomy are indicated on Fig. 6 View FIGURE 6 . The reproductive anatomy of L. macedonicus macedonicus is visualized on Fig. 7 C, F View FIGURE 7 , and the differences with L. graecus ( Fig. 7 G View FIGURE 7 ) are highlighted ( Fig. 7 F View FIGURE 7 ). According to our observation, the size and the shape of bursa copulatrix, hermaphrodite gland, and albumen gland vary and are not species-specific (compare P. Hesse, 1928).

Biology

Limax macedonicus macedonicus , unlike the members of the genus, seem to inhabit only open limestone habitats, rocks and rocky alpine pastures, up to 2000 m. Early in the morning, in cool foggy weather (at about 8.00 h, 11. July 2011), the subspecies of L. macedonicus macedonicus was registered to be actively crawling on the grassy vegetation and on stones. A large number of active young and adult specimens were found in depressions, which remain longer under shadow of rocks during the day. At midday and afternoon single specimens only were found inactive, concealed under stones even in sunny places.