Euceramus transversilineatus ( Lockington, 1878 )

Ferreira, Luciane Augusto De Azevedo & Anker, Arthur, 2021, An annotated and illustrated checklist of the porcelain crabs of Panama (Decapoda: Anomura), Zootaxa 5045 (1), pp. 1-154 : 21-24

Euceramus transversilineatus ( Lockington, 1878)

( Figs. 4 , 5 )

Porcellana transversilineata Lockington 1878: 396 , 405.

Euceramus transversilineatus .— Glassell 1938: 426, pl. 30; Haig 1960: 190, fig. 7(2), pl. 36, fig. 2; Abele & Kim 1989: 21.

Material examined. Panama [Pacific]: 1 ov. female, cl 8.4, cw 5.1 ( MZUSP 33494 ), Las Perlas Is., small rocky islet off north-eastern coast of Isla Saboga , depth at low tide 0.5 m, rock-sand bottom, strong current passage, deep under large rock on sand and small coral fragments, associated with holothurian, Holothuria sp. , leg. A. Anker, 21.04.2015 .

Previous records from Panama. Haig (1960); Abele & Kim (1989).

Distribution. East Pacific: Mexico and Panama (Taboga Is., Las Perlas Is., Panama Canal area) ( Glassell 1938; Haig 1960; Abele & Kim 1989; present study).

Ecology. Shallow subtidal, from just below the tide mark to 62 m. Glassell’s (1938) material came from “extreme low water, from the sand and shell material at the base of gorgonian corals”, as well as from “12 fathoms” (= 22 m). Haig (1960) reported E. transversilineatus from depths between 3.5 and 62 m, on sand, shell, sand and shell, sandy mud and sand with coralline algae bottoms. The single Las Perlas specimen was collected in slightly shallower conditions, about 0.5 m at spring low tide (> 3 m at high tide). It was found firmly clinging to a medim-sized sea cucumber, Holothuria sp. ( Fig. 5 ). The association of E. transversilineatus with holothurians has never been reported before, although it is presently unknown whether this porcelain crab is an obligate (or at least frequent) symbiont of holothurians or whether this finding is merely incidental.

Remarks. According to Glassell (1938), E. transversilineatus is more closely related to the western Atlantic E. praelongus than to its eastern Pacific congener E. panatelus , differing from both species by the carapace much shorter and with more distinct striations; the antennae shorter and not setose; the P2–P4 dactyli more uniform and falcate; and the telson longer relative to its width. In addition to the shape of the carapace, the two eastern Pacific can be easily separated by their colourations, creamy beige in E. transversilineatus ( Fig. 4 ) vs. white in E. panatelus ( Fig. 3 ).

Genus Heteroporcellana Haig, 1978

Figures

FIGURE 3. Euceramus panatelus Glassell, 1938: A, male (cl 8.4 mm, cw 3.7 mm) from Amador Causeway near Ciudad de Panamá, Panama (NHMW 23820), dorsal view; B, C, ovigerous female (cl 9.2 mm, cw 4.1 mm) from the same locality (NHMW 23820), dorsal (B) and ventral (C) views [photographs by AA].

FIGURE 4. Euceramus transversilineatus (Lockington, 1878):A–C, ovigerous female (cl 8.4 mm, cw 5.1 mm) from Las Perlas Islands, Panama (MZUSP 33494), dorsal (A), ventral (B) and frontal (C) views [photographs by AA].

FIGURE 5. Euceramus transversilineatus (Lockington, 1878):A, B, ovigerous female (cl 8.4 mm, cw 5.1 mm) from Las Perlas Islands, Panama (MZUSP 33494), showing association with a sea cucumber, Holothuria sp.; A, general view; B, close-up of the crab [photographs by AA].