Scyramathia A. Milne-Edwards, 1880

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 : 204-208

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.5977673
persistent identifier	https://treatment.plazi.org/id/03D4455B-F711-FFAC-FF59-F9C95CD22938
treatment provided by	Plazi
scientific name	Scyramathia A. Milne-Edwards, 1880
status

Treatment

Scyramathia A. Milne-Edwards, 1880 View in CoL

Scyramathia A. MILNE-EDWARDS, 1880 : 356.

Type species. Amathia carpenteri NORMAN IN WyVILLE THOMSON, 1873 [SUBSEQUENT DESIGNATION By RATHBUN 1925, GENDER FEMININE].

Included species. Scyramathia carpenteri (NORMAN IN WyVILLE THOMSON, 1873) [ Amathia ] (EA, MD), Scyramathia umbonata (STIMPSON, 1871) [ Scyra ] (WA); AND Scyramathia boschii (CASADíO, FELDMANN, PARRAS & SCHWEITZER, 2005) n. comb. [ Rochinia ] [ MIOCENE OF PUERTO MADRyN, ARGENTINA, WA].

Material examined. Scyramathia carpenteri (NORMAN IN WyVILLE THOMSON, 1873): 1 FEMALE, 1 JUVENILE ( MCZ 6543), WEST AFRICA, OFF CAPE BAJADOR, TALISMAN EXPEDITION, 9.VII.1883, 882M.

Scyramathia umbonata (STIMPSON, 1871): FEMALE, CL 32 MM, CW 23 MM (MNRJ 1581), HOLOTyPE OF Rochinia confusa TAVARES, 1991, BRAZIL, RIO DE JANEIRO, R/V “MARION DUFRESNE”, TAAF MD/ BRAZIL 1987 , STN 64 CB 105, 23°46’S, 42°09’W, 02.VI.1987, 592–610M; 3 MALES, 1 OVIGEROUS FEMALE, 1 JUVENILE FEMALE (USNM 1000819), GULF OF MEXICO , LOUISIANA , SOUTHWEST OF GRAND ISLAND , NGOMCS EXPEDITION, R/V “CITATION”, 27°42’44”N, 91°32’55”W, 543–783M; 1 OVIGEROUS FEMALE (USNM 1191773), UNITED STATES, R/V “ OREGON II ” , STN 11580, 29°11’N, 87°55’W, 10.III.1971, 640M, W. SANTANA DET.; 1 MALE (MOUFPE 15448), BRAZIL, REVIZEE NORTE, PROSPECçÃO III, LANCE 2, 03°43’N, 48°53’W, 15.XI.1996, 186M; 1 OVIGEROUS FEMALE (MOUFPE 15449), PERNAMBUCO , REVIZEE NORDESTE, CRUZEIRO V, STN. 117, 08°13,2’N, 34°33.3’W, 19.XI.1999, 575M; 1 MALE, 6 FEMALES (MNRJ 13694), ESPíRITO SANTO , REVIZEE PESCA, STN D–0503, 19°39.943’S, 38°30.435’W, 29.VI.1999, 808M; 1 MALE CL 32MM, CW 23 MM (MZUSP 17424), 24°13.300’S, 43°10.600’W, XI–XII.1997, 690M; 1 MALE CL 57 MM, CW 43 MM (MZUSP 16228), F/V "KINPO MARU", LANCE 123, NO EXACT LOCALITy OR DEPTH; 1 MALE (MOUFPE 15469), REVIZEE, CRUISE 5/00, STN. 14, NO EXACT LOCALITy OR DEPTH.

Diagnosis. (BASED ON FULLy DEVELOPED SPECIMENS) CARAPACE SUPRAORBITAL, PREORBITAL, HEPATIC, MESOGASTRIC, PROTO-, MESO-, METABRANCHIAL, CARDIAC, INTESTINAL TUBERCLES LARGE, FLAT-TOPPED, SHOWING AS LEAF-LIKE PLATES . PREORBITAL SCUTELLATE PLATE AND HEPATIC BOLETATE ORNAMENTATION FUSED TOGETHER INTO LARGE, LEAF-LIKE PLATE. LATERAL AND MESIAL MARGINS OF ANTENNAL ARTICLES 2 + 3 DISTINCTLy EXPANDED INTO LOBES. PTERyGOSTOMIAL TEETH COALESCENT AT BASE, RATHER INDISTINCT DISTALLy FORMING PROMINENT PTERyGOSTOMIAL RIDGE. MALE CHELIPED SLENDER, MUCH LONGER THAN P2. CHELIPED PROPODUS STRONGLy COMPRESSED LATERALLy, FORMING DISTINCT EDGE ALONG ITS ENTIRE LENGTH. MALE THORACIC STERNITE 8 EXTENDING LATERALLy BEyOND STERNO-ABDOMINAL CAVITy, LEFT UNCOVERED LATERALLy By ABDOMEN, VISIBLE IN VENTRAL VIEW. MALE THORACIC STERNITES 4–7 WITH ONE STRONG, TRANSVERSE RIDGE EACH. MALE FOURTH THORACIC STERNITE TRANSVERSE RIDGE UNINTERRUPTED MEDIALLy, COMPLETE, LOOPING AROUND FOLLOWING ANTERIOR MARGIN OF STERNO-ABDOMINAL CAVITy. G1 REACHING FAR BEyOND THORACIC STERNAL SUTURE 4/5, RATHER STRAIGHT PROXIMALLy AND MEDIALLy, DISTINCTLy CURVED INWARDS SUBDISTALLy, CONVERGENT ANTERIORLy, TAPERING TO BLUNT TIP, LATERAL MARGINS GENTLy CURVED INWARDS DISTALLy ( FIG. 13A, B View FIGURE 13 ).

Remarks. AS PREVIOUSLy MENTIONED, Scyramathia WAS ORIGINALLy ESTABLISHED FOR Amathia carpenteri AND Scyra umbonata , AND Scyramathia HAS LONG BEEN REGARDED AS A SyNONyM OF Rochinia A. MILNE-EDWARDS, 1875 (RATHBUN 1925; GRIFFIN & TRANTER 1986, TAVARES 1991; NG et al. 2008; TAVARES et al. 2016; LEE et al. 2017). HOWEVER, A COMPARISON BETWEEN S. carpenteri , S. umbonata AND Rochinia (BASED ON ITS TyPE SPECIES, R. gracilipes A. MILNE- EDWARDS, 1875) REVEALED THAT S. carpenteri AND S. umbonata CAN NO LONGER BE ATTRIBUTED TO Rochinia S. STR. THEREFORE, Scyramathia IS HEREIN RESURRECTED AS DISTINCT FROM Rochinia A. MILNE-EDWARDS, 1875 S. STR. Scyramathia AND Rochinia S. STR. DIFFER MARKEDLy FROM EACH OTHER IN THE FOLLOWING EIGHT CHARACTERS: 1) VERy STRONG MODIFICATIONS IN MORPHOLOGy OVER ONTOGENy REGARDLESS OF SEX, DURING WHICH THE CARAPACE SUPRAORBITAL, PREORBITAL, HEPATIC, MESOGASTRIC, PROTO-, MESO- AND METABRANCHIAL, CARDIAC, AND INTESTINAL TUBERCLES BECOME VERy LARGE, FLAT-TOPPED, LEAF- LIKE PLATES WHOSE CIRCUMFERENCES ARE BROADER THAN THE STEM IN FULL DEVELOPED SPECIMENS ( FIGS. 1A–D View FIGURE 1 , 12C View FIGURE 12 ), VS. ONLy SLIGHT CHANGES IN MORPHOLOGy OVER ONTOGENy IN Rochinia , IN WHICH THE CARAPACE IS FURNISHED WITH SUPRAORBITAL, PREORBITAL, HEPATIC, MESOGASTRIC, PROTO-, MESO- AND METABRANCHIAL, CARDIAC, AND INTESTINAL SPINES OR NODOSITIES IN FULL DEVELOPED SPECIMENS ( FIGS. 2A, B, E, F View FIGURE 2 , 9D View FIGURE 9 , 12A View FIGURE 12 ); 2) PREORBITAL SCUTELLATE PLATE AND HEPATIC BOLETATE ORNAMENTATION FUSED TOGETHER INTO A LARGE, LEAF-LIKE PLATE, WHOSE CIRCUMFERENCE IS MUCH BROADER THAN THE STEM ( FIG. 1B, C View FIGURE 1 ), VS. PREORBITAL AND HEPATIC PROMINENCES NOT FUSED TOGETHER, SPINIFORM IN Rochinia ( FIGS. 2A, B View FIGURE 2 , 9D View FIGURE 9 , 11A View FIGURE 11 ); 3) MALE THORACIC STERNITE 8 EXTENDING LATERALLy BEyOND THE STERNO-ABDOMINAL CAVITy, SO THAT IT IS LEFT UNCOVERED LATERALLy By THE ABDOMEN AND THUS VISIBLE IN VENTRAL VIEW ( FIG. 1D View FIGURE 1 ), VS. STERNITE 8 RESTRICTED TO THE STERNO-ABDOMINAL CAVITy, SO THUS CONCEALED By THE ABDOMINAL SOMITES AND THEREFORE NOT EXPOSED VENTRALLy IN Rochinia ( FIGS. 2C View FIGURE 2 , 10A, B View FIGURE10 ); 4) LATERAL AND MESIAL MARGINS OF THE ANTENNAL ARTICLES 2 + 3 DISTINCTLy EXPANDED INTO LOBES ( FIG. 1D View FIGURE 1 ), VS. ANTENNAL ARTICLES NOT EXPANDED INTO LOBES IN Rochinia ( FIG. 2D View FIGURE 2 ); 5) MALE THORACIC STERNITES 4–7 WITH ONE STRONG TRANSVERSE RIDGE EACH ( FIG. 1D View FIGURE 1 ), VS. NO THORACIC STERNAL TRANSVERSE RIDGES IN Rochinia ( FIG. 2C View FIGURE 2 ); 6) PTERyGOSTOMIAL TEETH COALESCENT AT THE BASE, RATHER INDISTINCT DISTALLy FORMING A PROMINENT PTERyGOSTOMIAL RIDGE ( FIG. 1B, D View FIGURE 1 ), VS. PTERyGOSTOMIAL TEETH VERy LOW, NOT COALESCENT ( FIG. 2B View FIGURE 2 ); 7) G1 REACHING FAR BEyOND THE THORACIC STERNAL SUTURE 4/5, VS. G1 REACHING AT MOST SLIGHTLy BEyOND THE SUTURE 4/5 IN Rochinia ; 8) MALE CHELIPEDS SLENDER, LONGER THAN P2, WITH THE PROPODUS STRONGLy LATERALLy COMPRESSED, FORMING A DISTINCT DORSAL EDGE ALONG ITS ENTIRE LENGTH IN FULL GROWN SPECIMENS (SEE TAVARES et al., 2016: FIG. 3H View FIGURE3 ), VS. CHELIPEDS DISTINCTLy MASSIVE, SHORT, MUCH SHORTER THAN P2 IN Rochinia ( FIGS. 2A, B View FIGURE 2 ). TAVARES (1991) SHOWED THAT THE RELATIVE LENGTH BETWEEN P1 AND P2 WAS A VALUABLE CHARACTER TO HELP DISTINGUISH BETWEEN GENERA. THE P1/P2 LENGTH RELATIVE TO EACH OTHER IN COMBINATION WITH OTHER MORPHOLOGICAL CHARACTERS WAS LATER USED By RICHER DE FORGES & NG (2009A) IN THE DIAGNOSIS OF THE GENERA Garthinia , Guinotinia , AND Laubierinia .

Scyramathia AND Rochinia ALSO DIFFER IN THEIR LARVAL STAGES (SEE INGLE 1979; LUPI & SPIVAK 2016). IN THE ZOEAL STAGES I AND II OF S. carpenteri , THE CARAPACE IS FURNISHED WITH ONE LATERAL SPINE AT EACH SIDE, VS. LATERAL SPINES ABSENT IN R. gracilipes ; THE ROSTRUM IS DISTINCTLy LONG IN S. carpenteri —AS LONG AS THE DORSAL SPINE, VS. MINUTE ROSTRUM IN Rochinia . IN THE MEGALOPAL STAGE OF S. carpenteri , THE CARAPACE HAS ONE STRONG CARDIAC SPINE AS WELL AS ONE SHORT SPINE IN THE BRANCHIAL REGION, VS. CARDIAC AND BRANCHIAL SPINES ABSENT IN R. gracilipes ; THE ROSTRUM IS REMARKABLy LONG IN S. carpenteri , VS. ROSTRUM VERy SHORT IN R. gracilipes ; AND THE PEREOPODS 2–4 WITH A COXAL AND ISCHIAL SPINE, VS. COXAL AND ISCHIAL SPINES ABSENT IN R. gracilipes .

Rochinia boschii CASADíO, FELDMANN, PARRAS & SCHWEITZER, 2005, DESCRIBED FROM THE MIOCENE OF PUERTO MADRyN, ARGENTINA, BASED ON yOUNG SPECIMENS WITH MAXIMUM CARAPACE WIDTH RANGING BETWEEN 20.2 MM AND 15.6 MM (CASADíO et al. 2005), CLOSELy RESEMBLES DEVELOPING SPECIMENS OF Scyramathia umbonata AND, ACCORDINGLy, IS TRANSFERRED TO Scyramathia .