Gilvossius candidus ( Olivi, 1792 )

Marin, Ivan, 2021, Burrowing mud shrimps (Decapoda: Axiidea & Gebiidea) of the northeastern Black Sea and their external parasites, Zootaxa 5039 (4), pp. 571-583 : 572-574

Gilvossius candidus ( Olivi, 1792)

( Fig. 1 a, b ; 2 a, c, e, g ; 3 a, c, d, g )

Cancer candidus Olivi, 1792: 51 , pl. 3 fig. 3.

Gebios davyanus Risso, 1822: 243

Callianassa subterranea forma pontica Czerniavsky, 1884: 81 (partim).

Callianassa pestae De Man, 1928: 34 , pl. 9, figs. 16-16e.

Callianassa algerica Lutze, 1938: 168 (partim).

Material examined. BLACK SEA : Crimean Peninsula : 2♂♂ ( ZMMU Ma-6193 and Ma-6194), 2 ovigerous ♀♀ ( ZMMU Ma-6195 and Ma-6196)— Kruglaya Bay (Omega), 44°35’51.8”N 33°26’40.8”E, depth 0.5–1.5 m, burrows in sand with sea grass, with yabbi pump, coll. I. Marin, 14.06.2020 ; 3♂♂, 5 ovigerous ♀♀ ( LEMMI)—same local- ity and date ; 2♂♂, 7 ovigerous ♀♀ ( LEMMI)— Kazachiya Bay , 44°34’10.8”N 33°24’47.1”E, burros in sand with sea grass, with yabbi pump, coll. I. Marin, 10.06.2020 ; Anapa Area : 1♂, 2 ovigerous ♀♀ ( LEMMI)— Anapa Beach, 44°55’13.4”N 37°18’45.8”E, depth 0.5–1.5 m, burrows in fine sand, with yabbi pump, coll. I. Marin, 7.08.2019 .

Remarks. The widely distributed species recorded from almost all soft bottom habitats along the northern coasts of the Black Sea , from intertidal to the depth of 30–40 meters, or may be deeper. It is also the largest species among the three callianassid species occurring in the area, reaching to 90 mm in the total body length in adult; males attain larger size than females. Differentiating characters between the present species and the sympatric congener G. tyrrhenus are noted under the account of the latter species.

From the related Gilvossius whitei (K. Sakai, 1999) , presently known only from Croatian coasts, the species can be separated by (after Sakai, 1999; Ngoc-Ho, 2003): the peduncle of antenna I is equal to the peduncle of antenna II ( Fig. 3 a ) (vs. the peduncle of antenna I is distinctly longer than that of antenna II in G. whitei (see Sakai, 1999: Fig. 4a ); the propodus of maxilliped III is about 1.5 times as long as wide, with convex lower border (vs. the propodus of maxilliped III is slender, twice as long as wide, with lower border nearly straight in G. whitei ) and longer telson, which is less than 1.5 times as wide as long ( Fig. 2 c, e ) (vs. about 1.5 times as wide as long in G. whitei ). The species can be also separated by the larger chela in males, with the carpus is distrinctly shorter than propodus, while the propodus is distinctly longer than the dactyls in G. candidus ( Fig. 3 c, d, g ; Sakai, 1999: Fig. 2c, d ), while the carpus is longer than the propodus, and the propodus is almost equal to the dactylus in length in G. whitei (see Sakai, 1999: Fig. 4c ).

For the difference from co-occurring G. tyrrhenus see below.

Parasites. The symbiotic copepods of the genus Clausidium Kossmann, 1874 ( Crustacea: Copepoda : Poecilostomatoida: Clausiididae), probably undescribed species, were found attaching to the carapace and pleon on these shrimps (see Marin & Turbanov, 2016). Unidentified scale worms ( Polychaeta: Polynoidae ) were also found in burrows of these mud shrimps.

Distribution. This species is mainly confined to the Mediterranean with a few records from nearby areas, Cádiz Gulf in southern Spain, and Algarve in southern Portugal ( Kurian, 1956; García Raso, 1983, 1985; Ngoc-Ho, 2003; Sakai, 2011); occurs from intertidal to the depth of 20–30 m on soft substrates from fine sand with or without sea grass to muddy sediments ( Dworschak, 1992). Previously, the species was also recorded from the northern Black Sea (e.g., Bãcescu, 1967; Dolgopolskaya, 1954, 1969; Kobyakova, & Dolgopol’skaya, 1969; Makarov, 1938, 2004; Marin, 2013; Marin & Turbanov, 2016).

Figures

FIGURE 1. Burrowing axiidean mud shrimps of the family Callianassidae from the north-eastern Black Sea, habitus (lateral view), live coloration and size comparison: Gilvossius candidus (Olivi, 1792) (a—♂, cl. 16.3 mm, ZMMU Ma-6193; b—ovigerous ♀, cl. 18.1 mm, ZMMU Ma 6195); Gilvossius tyrrhenus (Petagna, 1792) (c—♂, cl. 12.1 mm, ZMMU Ma 6197; d—ovigerous ♀, cl. 12.4 mm, ZMMU Ma 6199; Necallianassa truncata (Giard & Bonnier, 1890) (e—♂, cl. 9.8 mm, ZMMU Ma 6189; f—♂, cl. 8.9 mm, ZMMU Ma 6190; g—ovigerous ♀, cl. 9.6 mm, ZMMU Ma 6192).

FIGURE 2. Comparison of Gilvossius candidus (Olivi, 1792) (a, c, e, g) and Gilvossius tyrrhenus (Petagna, 1792) (b, d, f, h): a, b—front of carapace and PI, dorsal view, ♀♀ (LEMMI); c, d—telson and uropods, dorsal view, ♂♂ (LEMMI); e, f—telson and uropods, dorsal view, ♂♂ (LEMMI); g, h—uropods, lateral view, ♂♂ (LEMMI). Scale bar—5 mm.

FIGURE 3. Comparison of Gilvossius candidus (Olivi, 1792) (a, c, d, g) and Gilvossius tyrrhenus (Petagna, 1792) (b, e, f, h): a, b—front of carapace, ♂♂, dorsal view (LEMMI); c, e—major PI (cheliped), ♂♂, outer view (LEMMI); e, f—major PI (cheliped), ♂♂, internal view (LEMMI); g, h—minor PI (cheliped), ♀♀, outer view (LEMMI).

FIGURE 4. Necallianassa truncata (Giard & Bonnier, 1890) from the north-eastern Black Sea (a–c—♂, cl. 9.8 mm, ZMMU Ma 6189; d—♂, cl. 8.9 mm, ZMMU Ma-6190; e, f—♀, cl. 9.2 mm, ZMMU Ma 6191): a, b, e—habitus (a, e—dorsal; b—lateral views); c—major PI (cheliped), internal view; d—chela of major PI, internal view; f—telson and uropods, dorsal view.