Phimochirus holthuisi ( Provenzano, 1961 )

Lima, Daniel, Tavares, Marcos & Jr, Joel Braga De Mendonça, 2019, Paguroids (Decapoda: Anomura: Diogenidae and Paguridae) of the remote oceanic Archipelago Trindade and Martin Vaz, off southeast Brazil, with new records, description of three new species and zoogeographical notes, Zootaxa 4694 (1), pp. 1-63 : 51

Phimochirus holthuisi ( Provenzano, 1961)

Pylopagurus operculatus .— Holthuis 1959: 157, fig. 31 [not Phimochirus operculatus ( Stimpson, 1859) ]. Pylopagurus holthuisi Provenzano, 1961: 162 , fig. 3; Sanchéz 1977: 222, fig. 5B; Corredor et al. 1979: 33. Phimochirus holthuisi .— McLaughlin 1981a: 5; 1981b: 342, figs. 4c, 6a–c, 7c; Williams 1984: 225; Coelho & Ramos-Porto 1986: 42; Rieger 1998: 421; Melo 1999: 140, fig. 82; Coelho et al. 2007: 10, tab. 4; McLaughlin et al. 2010: 34; Nucci & Melo 2011: 36, figs. 1j, 2j, 3j; Lemaitre & Tavares 2015: 454.

Vitória-Trindade Seamounts specimens. 1 male sl 4.7 mm ( MZUSP 36187 ), Espírito Santo, Vitória-Trindade Seamounts Chain, Montague bank, TAFF MD/55 BRÉSIL 1987, stn 14/ DC 27 , 20°25’S, 36°42’W, M. Tavares coll., 14.v.1987, dredge, 81 m ; 1 male sl 2.4 mm ( MZUSP 36188 ), Brazil, Espírito Santo, Vitória-Trindade Seamounts Chain, Montague bank, TAFF MD/55 BRÉSIL 1987, stn 14/ DC 27 , 20°25’S, 36°42’W, M. Tavares coll., 14.v.1987, dredge, 81 m ; 1 male sl 2.6 mm, 1 female sl 2.5 mm ( MZUSP 32200 ), Brazil, Espírito Santo, Vitória-Trindade Seamounts Chain, Davis bank, TAFF MD/55 BRÉSIL 1987, stn 23/ DC 40 , 20°39’S, 34°41’W, M. Tavares coll., 15.v.1987, dredge, 60 m ; 1 male sl 4.3 mm, 1 female sl 2.8 mm ( MZUSP 36186 ), Brazil, Espírito Santo, Vitória- Trindade Seamounts Chain, Dogaressa bank, TAFF MD/55 BRÉSIL 1987, stn 24/ DC 42 , 20°55’S, 34°01’W, M. Tavares coll., 17.v.1987, dredge, 60 m ; damaged specimen ( MZUSP 18632 ), Brazil, São Paulo, Ubatuba, Enseada de Ubatuba , xii.2000, 40 m .

Comparative material examined. Phimochirus holthuisi : 1 male sl 13.8 mm ( USNM 1163141 ), Gulf of Mexico, United States, off Florida, 26°45’46”N, 82°43’07”W, Continental Shelf Associates for BLM/ MMS coll., 2.v.1981, dredge, 24 m; 1 ovigerous female sl 3.9 mm ( MZUSP 7221 ), Brazil, Pará, Projeto Geomar, stn 151.

Phimochirus occlusus ( Henderson, 1888) : 5 specimens ( MZUSP 13859 ), São Paulo, Projeto REVIZEE , stn 6661, 147 m; 21 specimens ( MZUSP 13881 ), Brazil, Rio de Janeiro, Cabo Frio , 350–400 m.

Type locality. 4.5 miles Southeast of Ram’s Head, St. John Island , Virgin Islands, USA, between 15–18 m.

Distribution. United States (North Carolina to Florida), Bahamas, Gulf of Mexico, Colombia, Guyanas and Brazil (Pará, Pernambuco, Bahia, São Paulo, and the Vitória-Trindade Seamounts Chain, present study), between 1 and 120 m.

Remarks. Phimochirus holthuisi is closely related to P. operculatus ( Stimpson, 1859) , also from the western Atlantic. However, whereas in P. holthuisi the middorsal surface of the minor cheliped palm is elevated, unarmed or provided with only a few, small spinules or tubercles proximally, in P. operculatus it is provided with a row of small spines or spinules extending to the distal margin next to the dactyl. Phimochirus holthuisi further differs from P. operculatus in that the ventral margin of the minor cheliped merus is armed with one strong spine and a few smaller spines or spinules, instead of a row of strong spines as in P. operculatus ( McLaughlin 1981b) .

As noted by McLaughlin (1981b), in Phimochirus the more taxonomically helpful characters are found on the left cheliped. As already pointed out by McLaughlin (1981b) for northern specimens, the moderate to large specimens from the Vitória-Trindade Seamounts Chain tend to have larger tubercles on the dorsal surface of the major cheliped fixed finger and palm distally, whilst smaller specimens superficially resemble P. operculatus in having granular or weakly tuberculate fixed finger and palm dorsodistally.

Phimochirus holthuisi mainly occurs in depths exceeding 30 m down to 210 m, in shell, sand, mud and coral bottoms ( McLaughlin 1981b; Williams 1984). In the Vitória-Trindade Seamounts Chain (Montague, Davis and Dogaressa, this report) it occurred in sandy coral rubble sable between 60 and 81 m.