Megalobrachium festae ( Nobili, 1901 )

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 : 24-25

Megalobrachium festae ( Nobili, 1901)

( Fig. 6 )

Porcellanides festae Nobili 1901: 21 . Porcellanopsis festae .— Rathbun 1910: 601. Megalobrachium festae . — Gore 1982: 6. Megalobrachium festai . — Haig 1957b: 15; Haig 1960: 226, pl. 16, fig. 10, pl. 40, fig. 3; Gore 1982: 6; Hiller et al. 2004: 3;

Lazarus-Agudelo & Cantera-Kintz 2007: 229; García-Madrigal & Andréu-Sánchez 2009: 26, fig. 2A; Hiller & Lessios

2019: 414, fig. 1b.

Material examined. Panama [Pacific]: 2 males, cl 4.9, cw 5.0 and cl 3.8, cw 3.9 ( MZUSP 33142 ), Río Mar , rocksand intertidal at low tide, in rock crevices, leg. A. Anker & J.F. Lazarus-Agudelo, 20.03.2015 .

Previous records from Panama. Gore (1982).

Distribution. East Pacific: Mexico, El Salvador, Panama (vicinity of Ciudad de Panamá, Río Mar), Colombia and Ecuador ( Haig 1960; Gore 1982; Hiller et al. 2004; present study).

Ecology. Rock-sand intertidal and shallow subtidal, known depth range: 0–9 m; typically under rocks and in rock crevices, but also in sponges and dead corals, among hydrozoans or inside (probably dead) bivalves ( Haig 1960; Gore 1982; Hiller et al. 2004).

Remarks. Megalobrachium festae (often spelled as M. festai , see Osawa & McLaughlin 2010 for discussion) is morphologically very similar to its western Atlantic sister species M. roseum ( Rathbun, 1900) (Hiller & Lessios 2019) , especially in the structure and ornamentation of the P1–P4. However, in M. festae ( Fig. 6 ), the carapace is subtriangular and with larger tubercles; the P2–P4 are more robust; and the telson possesses five plates vs. seven in M. roseum ( Haig 1960) .

Figures

FIGURE 6. Megalobrachium festae (Nobili, 1901): male (cl 4.9 mm, cw 5.0 mm) from Río Mar, Panama (MZUSP 33142), dorsal view [photograph by AA].