Minyorhyncha crassa (A. Milne-Edwards, 1879) Tavares & Santana, 2018

Tavares, Marcos & Santana, William, 2018, Refining the genus Rochinia A. Milne-Edwards, 1875: reinstatement of Scyramathia A. Milne-Edwards, 1880 and Anamathia Smith, 1885, and a new genus for Amathia crassa A. Milne-Edwards, 1879, with notes on its ontogeny (Crustacea: Brachyura: Epialtidae), Zootaxa 4418 (3), pp. 201-227 : 213-219

publication ID	https://doi.org/ 10.11646/zootaxa.4418.3.1
publication LSID	lsid:zoobank.org:pub:7E1693CB-B902-422F-9C5E-C1A0FCEA809C
DOI	https://doi.org/10.5281/zenodo.6490621
persistent identifier	https://treatment.plazi.org/id/03D4455B-F71E-FFB9-FF59-FB905F4C2CDB
treatment provided by	Plazi
scientific name	Minyorhyncha crassa (A. Milne-Edwards, 1879)
status	gen. nov.

Treatment

Minyorhyncha crassa (A. Milne-Edwards, 1879) View in CoL n. gen., n. comb.

( FIGS. 4A–D View FIGURE 4 , 5A–D View FIGURE 5 , 6A–D View FIGURE 6 , 7A–D View FIGURE 7 , 8 View FIGURE 8 , 9A–C View FIGURE 9 , 10A, B View FIGURE10 , 11B View FIGURE 11 , 12D View FIGURE 12 )

Amathia crassa A. MILNE-EDWARDS, 1879 : 203, pL. 28, fIG. 2.

Amathia agassizii SmITH, 1882 : 1, pL. 2, fIGS. 2, 3.

Anamathia crassa —SmITH 1885: 493.

Scyramathia crassa— A. MILNE-EDWARDS & BOuVIER 1923: 380.

Rochinia crassa —RATHbuN 1925: 210, pLS. 68, 69, 226; PEquENAT 1970: 183; WILLIAmS 1984: 322, fIGS. 256, 260A; GRIffIN & TRANTER 1986: 175; NG et al. 2008: 105.

Material examined. HOLOTyPE, MALE CL 15.2 MM , CW 11.5MM (MCZ 2862), UNITED STATES: FLORIDA , SOUTH OF MARQUESAS KEyS, “BLAKE”, BLAKE EXPEDITIONS, STN. 0 5, 24°15’0”N, 82°13’0”W, 278–419M; MALE CL 27.5 MM, CW 20.3 MM (MCZ 3174), LECTOTyPE OF Amathia agassizii SMITH, 1882 , OFF SOUTH CAROLINA, “ BLAKE ” , BLAKE EXPEDITIONS, STN 319, 32°25’0”N, 77°42’30”W, 13.VII.1880, 479M; 2 JUVENILE MALES (USNM 1191762), FLORIDA , GULF OF MEXICO, “OREGON II” , STN 11582, 29°12’N, 87°46’W, 03.X.1971, W. SANTANA DET.; 1 FEMALE (USNM 1191755), FLORIDA , GULF OF MEXICO, “OREGON II” , STN 11498, 29°06’N, 86°48’W, 30.VI.1971, 448M, W. SANTANA DET.; 1 FEMALE (USNM 1191764), FLORIDA , GULF OF MEXICO, “OREGON II” , STN 11560, 28°36’N, 89°00’W, 29.IX.1971, 439M, W. SANTANA DET. 1 MALE, 1 OVIGEROUS FEMALE (USNM 1191754), FLORIDA , GULF OF MEXICO, “OREGON II” , STN 10907, 28°36’N, 86°15’W, 09.II.1970, W. SANTANA DET.; 2 JUVENILE MALES (USNM 1191764), FLORIDA , GULF OF MEXICO, “OREGON II” , STN 11484, 28°24’N,85°59’W, 25.VI.1971, W. SANTANA DET.; 5 JUVENILES (USNM 1002943), FLORIDA , GULF OF MEXICO, “ FISH HAWK ” , STN 7514, 28°17’36”N, 86°14’48”W, 16.IV.1984, TRAWL, W.E. PEQUEGNAT DET.; 1 MALE (USNM 1191763), FLORIDA , GULF OF MEXICO, “OREGON II” , STN 11481, 24.VI.1971, 28°02’N, 85°37’W, 585M, W. SANTANA DET.; 2 MALES, 1 FEMALE, 8 JUVENILES (USNM 46789), FLORIDA , GULF STREAM OFF CAPE FLORIDA, 25.III.1903 ; 1 JUVENILE (USNM 1178577), FLORIDA , GULF OF MEXICO , GREEN CANyON 234, “JOHNSON SEA LINK”, CRUISE 4712, CHEMO EXPEDITION, 27°44’46”N, 91°13’16”W, 10.VII.2004, 534M; 1 JUVENILE (USNM 1178576), FLORIDA , GULF OF MEXICO , GREEN CANyON 234, “JOHNSON SEA LINK”, CRUISE 4570, CHEMO EXPEDITION, 27°44’46”N, 91°13’16”W, 26.VIII.2003, 534M; 1 FEMALE (USNM 1256353), GULF OF MEXICO, “OREGON II” , STN. 11145, 24°25’N, 87°50’W, 13.VIII.1970, W. SANTANA DET., 585M; 5 MALES, 1 OVIGEROUS FEMALE (MOUFPE 15447), BRAZIL, CEPEMAR, STN. MT63, 08.V.2011; 1 MALE CL 49 MM, CW 39 MM, 1 OVIGEROUS FEMALE (MZUSP 15710), SÃO PAULO, R/V “ NUEVO APENINO ” , STN LANCE 36, 24°15.00’S, 44°33.00’W, 24.VI.2002, 367M; 1 MALE (MZUSP 24352), SÃO PAULO, R/V “ BELEM ”, BETWEEN 24 °18’39.600”S, 43°51’10.800”W AND 25°4’3.000”S, 44°58’22.800”W GoogleMaps , 18.VII.2002; MALE, CL 100 MM, CW 86 MM (MZUSP 13816), SÃO PAULO, 25°08’S, 44°53’W, E GoogleMaps . RODRIGUES COLL.; 1 OVIGEROUS FEMALE (MZUSP 21762), SANTA CATARINA, ITAJAí, R/V “SOLONCy MOURA ” , STN 5, BETWEEN 26°48.178”S, 46°34.653”W AND 26°47.027”S, 46°35.270”W, 310M; 1 MALE CL 51 MM, CW 42 MM, 1 FEMALE CL 16, CW 12 (MZUSP 12898), SANTA CATARINA , PADCT, STN 6637, 27°00.500’S, 46°36.800’W, H.B. SOBREIRA DET., 323M; MALE CL 58 MM, CW 46 MM, 3 MALES, 3 FEMALES (MZUSP 12843), SANTA CATARINA , PADCT, STN 6634, 27°18.9’S, 47°5.2’W, 1967, G.A.S. MELO DET., 310M; 1 MALE CL 23 MM, CW 18 MM, 1 JUVENILE FEMALE CL 29 MM, CW 23 MM (MZUSP 28395), R/ V “SOLONCy MOURA”, STN E15, 21.X.2008, 500M; 1 MALE CL 86 MM, CW 72 MM, 2 OVIGEROUS FEMALES (MZUSP 28397), R/V “SOLONCy MOURA”, STN PONTO 11, 10.XII.2007; 1 JUVENILE MALE CL 16 MM, CW 12 MM (MZUSP 16476), COLLETING LOCALITy UNKNOWN, 15.X.2002, M. TAVARES DET.

Distribution. MID-ATLANTIC RIDGE, REyKJANES RIDGE (59°N) (COPLEy et al. 1996). WESTERN ATLANTIC: NOVA SCOTIA, CANADA (MORIyASU et al. 2001); EAST COAST OF THE UNITED STATES (FROM MARTHA’S VINEyARD TO FLORIDA), GULF OF MEXICO, CARIBBEAN SEA, NORTH COAST OF SOUTH AMERICA TO BRAZIL (FROM AMAPÁ TO SANTA CATARINA); BETWEEN 66 AND 1216 M OF DEPTH (WILLIAMS 1984).

Remarks. CHANGES OVER ONTOGENy IN Minyorhyncha crassa (A. MILNE-EDWARDS, 1879) n. gen., n. comb., HAVE BEEN SCARCELy DOCUMENTED IN THE LITERATURE. RATHBUN (1925: 211) REMARKED THAT THE ROSTRAL HORNS DIMINISH IN LENGTH WITH AGE AND PEQUEGNAT (1970) NOTICED THAT DEVELOPING SPECIMENS HAVE PROPORTIONALLy MUCH LONGER SPINES THAN FULLy DEVELOPED SPECIMENS. WILLIAMS (1984) REMARKED THAT IN DEVELOPING SPECIMENS THE CARAPACE MEDIAN CARINA BEARS ONLy FIVE SPINES (INSTEAD OF SIX IN THE ADULTS) AND THE P2 ANTERIORLy SURPASSES THE CHELIPEDS.

ACTUALLy, THE ONTOGENETIC VARIATION IN Minyorhyncha crassa n. gen., n. comb. IS SUCH THAT yOUNG SPECIMENS CAN EASILy BE MISTAKEN FOR A DIFFERENT SPECIES FROM THE ADULT. SUCH IS THE CASE OF Minyorhyncha agassizii (SMITH, 1882) n. gen., n. comb. ( FIG. 9A, B View FIGURE 9 ) (ORIGINAL COMBINATION: Amathia agassizii ), WHICH PROVED TO BE BUT AN ONTOGENETIC STAGE OF M. crassa n. gen., n. comb. (SMITH 1882; 1883; RATHBUN 1925). SMITH (1882: 2) BASED THE DESCRIPTION OF M. agassizii n. gen., n. comb. ON TWO SPECIMENS AND, WHILE DESCRIBING THE SMALLER ONE, REMARKED THAT IT "DIFFERS SO MUCH FROM THE ONE ABOVE DESCRIBED [THE LARGER ONE] THAT IT MIGHT READLy BE MISTAKEN FOR A DISTINCT SPECIES.". INDEED, THE MAIN DIAGNOSTIC CHARACTERS OF M. crassa n. gen., n. comb. CAN BE READILy RECOGNIZED IN Minyorhyncha agassizii n. gen., n. comb. ( FIG. 9A, B View FIGURE 9 ): 1) CARAPACE BRANCHIOSTEGAL REGION WITH A ROW OF STRONG, ACUTE SPINES ALONG MOST OF THE POSTEROINFERIOR HALF OF THE LINE OF DEHISCENCE ( FIG. 5B–D View FIGURE 5 ); 2) TRANSVERSE ROW OF STRONG, ACUTE SPINES EXTENDING ABOVE THE POSTERIOR MARGIN OF THE CARAPACE AND RUNNING ACROSS THE INTESTINAL REGION ( FIG. 6D View FIGURE 6 ), AND 3) ANTENNAL SEGMENT 2+3 WITH ONE ANTERO-VENTRO-LATERAL AND ONE POSTERO-VENTRO-LATERAL, NEARLy EQUAL IN SIZE, STRONG SPINES ( FIGS. 5D View FIGURE 5 , 6B View FIGURE 6 , 7D View FIGURE 7 , 9B View FIGURE 9 ).

IN FULLy DEVELOPED SPECIMENS OF M. crassa n. gen., n. comb. (E.G. CL 96 MM, CW 77 MM) THE LONGITUDINAL CARINA ALONG THE MIDLINE OF THE CARAPACE IS WELL MARKED; THE POSTERIOR CARDIAC CENTRAL SPINE IS ONLy A LITTLE SMALLER THAN THE ANTERIOR CARDIAC CENTRAL SPINE REGARDLESS OF SEX ( FIG. 5C, D View FIGURE 5 ); THE MALE CHELIPED MERUS AND PROPODUS ARE COVERED WITH SPINULES ( FIG. 8 View FIGURE 8 ); THE ROSTRUM IS SHORT AND STRAIGHT ( FIG. 4D View FIGURE 4 ); AND THE CARAPACE REGIONS ARE WELL DELIMITED, THE MESOGASTRIC, BRANCHIAL, AND CARDIAC REGIONS MARKEDLy SWOLLEN, AND THE CERVICAL, HEPATIC, AND CARDIO-INTESTINAL GROOVES WELL MARKED ( FIGS. 4D View FIGURE 4 , 5D View FIGURE 5 , 6A View FIGURE 6 ). IN CONTRAST, IN DEVELOPING SPECIMENS (E.G. CL 15 MM, CW 10 MM) THE LONGITUDINAL CARINA ALONG THE MIDLINE OF THE CARAPACE IS INDISTINCT ( FIG. 4A, B View FIGURE 4 , 5A, B View FIGURE 5 ); THE POSTERIOR CARDIAC CENTRAL SPINE IS ONLy A MINUTE, ALMOST IMPERCEPTIBLE TUBERCLE ( FIG. 5A, B View FIGURE 5 ) ; THE MALE CHELIPED MERUS AND PROPODUS ARE INITIALLy SMOOTH, GRADUALLy BECOMING SPINULATE WITH GROWTH; THE ROSTRUM IS MUCH LONGER, ATTAINING HALF OF THE CARAPACE LENGTH, AND STRONGLy DIVERGENT ( FIGS. 4A, B View FIGURE 4 , 5A, B View FIGURE 5 ); THE CARAPACE REGIONS ARE POORLy DELIMITED, THE MESOGASTRIC, BRANCHIAL AND CARDIAC REGIONS NOT SWOLLEN, AND THE CERVICAL, HEPATIC AND CARDIO-INTESTINAL GROOVES INDISTINCT ( FIG. 4A, B View FIGURE 4 ). IT IS WORTH NOTING, HOWEVER, THAT SOME OF THE UNIQUE CHARACTERS OF Minyorhyncha crassa n. gen., n. comb. ARE PRESENT DURING THE ONTOGENETIC STAGES AND STILL PRESENT IN THE ADULT STAGE, SUCH AS SPINATION OF THE THE ANTENNAL SEGMENT 2 +3 ( FIGS. 7A–D View FIGURE 7 , 9B View FIGURE 9 ); 2) , THE ROW OF SPINES RUNNING ACROSS THE BRANCHIOSTEGAL AND METABRANCHIAL REGIONS ( FIG. 5A–D View FIGURE 5 ); THE SPINATION OF THE POSTERIOR MARGIN OF THE CARAPACE ( FIGS. 4A–D View FIGURE 4 , 6D View FIGURE 6 , 9A View FIGURE 9 ); AND THE POSTERIOR CARDIAC SPINE ( FIG. 5A–D View FIGURE 5 ).