Trizocarcinus tacitus Chace, 1940

CASTRO, PETER & NG, PETER K. L., 2010, Revision of the family Euryplacidae Stimpson, 1871 (Crustacea: Decapoda: Brachyura: Goneplacoidea), Zootaxa 2375 (1), pp. 1-130 : 110-112

publication ID

https://doi.org/ 10.11646/zootaxa.2375.1.1

persistent identifier

https://treatment.plazi.org/id/03F487A8-3931-424B-7D8C-FEA1F69DF8A1

treatment provided by

Felipe

scientific name

Trizocarcinus tacitus Chace, 1940
status

 

Trizocarcinus tacitus Chace, 1940 View in CoL

( Figs. 45A, B View FIGURE 45 ; 46G–M View FIGURE 46 )

Goneplax tridentata — Boone 1927: 10, figs. 2–4 [ Belize]; 1930: 194, pl. 66, fig. A [Florida]. [not Trapezioplax tridentata (A. Milne-Edwards, 1880) View in CoL ; Pseudorhombilidae View in CoL ]

Trizocarcinus tacitus Chace, 1940: 41 View in CoL , figs. 15, 16 [ Barbados]; 1956: 20 [Gulf of Mexico]. — Guinot 1969b: 518, 522 [discussion], figs. 34, 43, 45, 50, 51 [holotype]; 1971: 1081 [in list]. — Soto 1985: 484, 495; 1986: 3, 4, 36; 1991: 626, 627 [Florida]. — McLaughlin et al. 2005: 257 [in list]. — Ng et al. 2008: 78 [in list].

Type material. Male holotype ( MCZ 5646 View Materials ) .

Type locality. West Indies , Barbados, 272 m.

Material examined. Bahamas. Grand Bahama, Gerda , stn. 696, 26°28’N, 78°43’W, 22.07.1965: 1 male, 14.0 mm × 18.0 mm ( RMNH D 26876) GoogleMaps .

Florida. Florida Straits , SW of Dry Tortugas, 24.3629°N, 83.2277°W, F. F. Snelson coll., 9.05.2006: 1 male, 11.5 mm × 15.2 mm ( UF 11583 ) GoogleMaps .

Gulf of Mexico. Oregon, stn. 273, U.S. Fish & Wildlife Service, 1951: 1 female, 23.3 mm × 31.5 mm ( USNM 92164 View Materials ) .

Guadeloupe. Mission ORSTOM, IRPM, SMCB: stn. C34, off Basse Terre, 16°22.49’N, 61°48.99’W, 405 m, G. Leblond & J. Poupin, 04.1993: 1 female, 20.6 mm × 29.4 mm ( MNHN-B30602 ) GoogleMaps .

St. Vincent. Pillsbury , stn.876, 13°18.9’N, 61°04.7’W, 231–258 m, 06.07.1969: 1 female, 18.5 mm × 26.3 mm ( RMNH D 26875) GoogleMaps .

Diagnosis. Dorsal, ventral surface of carapace smooth, not granular ( Fig. 45 View FIGURE 45 ). Stridulating ridge absent on pterygostomian region. G1 apex not particularly long ( Fig. 46K, L View FIGURE 46 ).

Remarks. Trizocarcinus tacitus , which is Western Atlantic in distribution, can be differentiated from its Tropical Eastern Pacific congener, T. dentatus , by having a characteristically smooth carapace, not granular as in the latter. Other characters separating the two species are given in the Remarks for T. dentatus .

Distribution. Western Atlantic from the Bahamas and the Gulf of Mexico to St. Vincent, West Indies. Depth: 187– 462 m.

Genus Villoplax n. gen.

Trizocarcinus View in CoL — Karasawa & Kato, 2003a: 151 [in list]; 2003b: 139 [in list] [part]. — Ng & Castro 2007: 44 [in list] [part]. — Ng et al. 2008: 78 [in list] [part]. (not Trizocarcinus Rathbun, 1914 View in CoL )

Diagnosis. Carapace ( Figs. 47A, B View FIGURE 47 ; 48A View FIGURE 48 ) quadrate, slightly wider than long, dorsal surface minutely granular, without clear indication of regions; anterolateral borders nearly straight; front wide, straight or slightly bilobed, with small median notch. One triangular anterolateral tooth with acute tips posterior to narrowly triangular, acute, anteriorly oriented outer orbital tooth. Orbits ( Figs. 47C View FIGURE 47 ; 48B View FIGURE 48 ) moderately transversely long (nearly as long as front); thin supraorbital margin, with 2 notches; short inner suborbital tooth, sinuous median lobe, outer notch on granular suborbital border ( Figs. 47C View FIGURE 47 ; 48B View FIGURE 48 ); eye peduncles moderately long, shorter than front, approximately as long as corneas; large, spherical corneas. Basal antennal article immobile, orbital hiatus is closed excluding antennal flagellum from orbit ( Fig. 47C View FIGURE 47 ). Anteroexternal margin of third maxilliped merus auriculiform ( Figs. 47C View FIGURE 47 ; 48B View FIGURE 48 ). Cheliped fingers slender, dorsoventrally flattened, slightly shorter than propodus, light in colour; carpus with acute, curved tooth on inner margin; tomentum long, conspicuous, on outer surface of propodus, carpus, anterior margin of merus ( Figs. 47A View FIGURE 47 ; 48A, C View FIGURE 48 ). Dorsal margins of ambulatory legs (P2–P5) meri, carpi, propodi unarmed, dactyli slender, smooth, with conspicuous tomentum along margins; P5 propodus, dactylus long, slender, fringed with many short setae ( Figs. 47A View FIGURE 47 ; 48A View FIGURE 48 ). Thoracic sternum wide; thoracic suture 2/3 complete, convex, close to anterior margin ( Figs. 47D View FIGURE 47 ; 48B View FIGURE 48 ); 3/4 deep, short, interrupted; 4/5, 6/7, 7/8 interrupted, 5/6 complete; median groove on thoracic sternites 7, 8. Sterno-abdominal cavity of male deep, reaching anterior margin of sternite 4 ( Fig. 47D View FIGURE 47 ). Press-button of male abdominallocking mechanism as large tubercle near thoracic suture 4/5 (small tubercle present in pre-adult female holotype). Male abdomen proportionally wide, triangular (not T-shaped), telson longer than wide ( Figs. 47D View FIGURE 47 ; 48D View FIGURE 48 ); somite 3 only slightly transversely shorter than somites 4–6, reaching inner margins of P5 coxae, fitting under episternite 7; no portions of thoracic 8 exposed by closed abdomen, somite 2 transversely almost as long as somite 3 ( Fig. 48D View FIGURE 48 ). G1 long, slender, slightly sinuous, thin distal part, acuminate apex, with many denticles ( Fig. 48E, F View FIGURE 48 ); G2 less than one-third of G1, apex with 2 unequal processes ( Fig. 48G View FIGURE 48 ). Male genital opening (gonopore) coxal; coxo-sternal disposition of long penis, protected by slightly convex posterior portion of thoracic sternite 7. Vulva of adult female unknown but, ovoid, transversely near median portion of sternite 6 in pre-adult female.

Type species. Trizocarcinus peruvianus Garth, 1973 View in CoL (by present designation, gender feminine).

Etymology. From villosus Latin for “hairy”, in reference to the thick tomentum on the chelipeds of the only species included in the new genus, Villoplax peruvianus , and plax Greek for “plate” or “tablet”, a common suffix also used for many related goneplacoid genera.

Remarks. The only species included in the new genus, V. peruvianus ( Garth, 1973) was described as a species of Trizocarcinus . Although sharing with Trizocarcinus a triangular male abdomen, the new genus departs from the two species included in Trizocarcinus by several characters related to carapace shape (straight anterolateral border each with one anterolateral tooth but arched with two teeth in Trizocarcinus ), morphology of the orbits (thin, acute outer orbital tooth and an inner suborbital tooth in contrast to a triangular outer orbital tooth and the absence of an inner suborbital tooth in Trizocarcinus ), and thoracic suture 2/3 (close to the thoracic margin but broad space between suture and margin in Trizocarcinus ) (also see Remarks for Trizocarcinus and Table 1).

Species included. Trizocarcinus peruvianus ( Garth, 1973) The genus is restricted to the Tropical Eastern Pacific region.

RMNH

National Museum of Natural History, Naturalis

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Euryplacidae

Genus

Trizocarcinus

Loc

Trizocarcinus tacitus Chace, 1940

CASTRO, PETER & NG, PETER K. L. 2010
2010
Loc

Trizocarcinus

Ng, P. K. L. & Guinot, D. & Davie, P. 2008: 78
Ng, P. K. L. & Castro, P. 2007: 44
Karasawa, H. & Kato, H. 2003: 151
2003
Loc

Trizocarcinus tacitus

Ng, P. K. L. & Guinot, D. & Davie, P. 2008: 78
McLaughlin, P. A. & Camp, D. K. & Angel, M. V. & Bousfield, E. L. & Brunel, P. & Brusca, R. C. & Cadien, D. & Cohen, A. C. & Conlan, K. & Eldredge, L. G. & Felder, D. L. & Goy, J. W. & Haney, T. & Hann, B. & Heard, R. W. & Hendrickx, E. A. & Hobbs, H. H. & Holsinger, J. R. & Kensley, B. & Laubitz, D. R. & LeCroy, S. E. & Lemaitre, R. & Maddocks, R. F. & Martin, J. W. & Nikkelsen, P. & Nelson, E. & Newman, W. A. & Overstreet, R. M. & Poly, W. J. & Price, W. W. & Reid, J. W. & Robertson, A. & Rogers, D. C. & Ross, A. & Schotte, M. & Schram, F. R. & Shih, C. - T. & Watling, L. & Wilson, G. D. F. & Turgeon, D. D. 2005: 257
Soto, L. A. 1985: 484
Guinot, D. 1969: 518
Chace, F. A. 1940: 41
1940
Loc

Goneplax tridentata

Boone, L. 1927: 10
1927
Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF