Alpheus petronioi, Almeida & Terossi & Mantelatto, 2014

Almeida, Alexandre O., Terossi, Mariana & Mantelatto, Fernando L., 2014, Morphology and DNA analyses reveal a new cryptic snapping shrimp of the Alpheus heterochaelis Say, 1818 (Decapoda: Alpheidae) species complex from the western Atlantic, Zoosystema 36 (1), pp. 53-71 : 57-62

Alpheus petronioi n. sp.

( Figs 1-3 ; 4C, D )

Alpheus sp. nov. 1 – Christoffersen 1980a: 236.

Alpheus heterochaelis – Christoffersen 1984: 200, figs 5-7; 1998: 358; Barros & Pimentel 2001: 21; Coelho et al. 2006: 51 (in part); Almeida et al. 2006: 9, fig. 6; 2012: 11; Soledade & Almeida 2013: 100 (not A. heterochaelis Say, 1818: 243 ).

Alpheus andronyx Christoffersen, 1998: 358 (nomen nudum).

Alpheus cf. heterochaelis – Rodrigues et al. 2009: 336 (identity to be confirmed).

TYPE MATERIAL. — Holotype male (CL 11.1 mm): Brazil, Pará , São Caetano de Odivelas, estuary of the Mojuim River, coll. A. O. Almeida, G. O. Soledade & P. S. Santos, 16.XI.2012, under rocks, mud-sand bottom, salinity 31 ( MZUSP 28314 ). Paratypes:1 ovf (CL 10.6 mm, forming a pair with the holotype), same data as the holotype ( MZUSP 28315 ) ; 1 ♂, 1 ♀, same data as the holotype ( CCDB 4509 ) ; 13 ♂♂, 15 ♀♀ (8 ovf), same data as the holotype ( UESC 1533 ) ; 1 ♂, 1 ♀, same data as the holotype (MNHN-IU-2013-8627) .

ETYMOLOGY. — It is our great pleasure to name this new species in honor of the late Brazilian carcinologist, Prof. Dr Petrônio Alves Coelho (Universidade Federal de Pernambuco, Recife, Brazil) in recognition of his dedication and contributions to the knowledge of South American crustaceans.

MATERIAL EXAMINED. — Colombia. 1 ♂, Caribbean coast of Colombia, Golfo de Morrosquillo, Bahía Cispata, Punta Calixto, mangroves just outside entrance to canal of Ciénaga de Soledad , St. #6, trap, coll. R. Lemaitre, 04.III.1997 ( USNM 1171071 ) ; 1 ♂, 1 ovf, Department of Magdalena, Magdalena Delta, Los Cocos, Cano Atascosa, northeastern Barranquilla , colls H. Türkay & M. Türkay, 27.X.1978 ( SMF 9901 ) .

Venezuela. 2 ♂♂, 2 ♀♀, Orinoco Delta, XI-5226, coll. G. Pereira, 2003, AA fcn 03-031 ( OUMNH. ZC. 2011-06.001) ; 1 ovf, manglar la Rosita, colls J. Delgado & A. Godoy, 14.VI.1995 ( OUMNH. ZC. 2011-06.014) .

Brazil. Pará , same data as the holotype, 10 ♂♂, 10 ♀♀ (2 ovf) ( UESC 1534 ) ; 2 ♀♀, Pará, Salinópolis, estuary near Maçarico Beach (00°35’49.24”S; 47°20’35.36”W), coll. F. L. Carvalho, L. Pileggi, R. Robles & E. Souza- Carvalho, 15.XI.2012 ( CCDB 4426 ) ; 4 ♂♂, Pará, São João de Pirabas , city harbor (00°46’01.21”S; 47°10’12.4”W), coll. F. L. Carvalho, L. Pileggi, R. Robles & E. Souza- Carvalho, 16.XI.2012 ( CCDB 4443 ) ; 1 ♂, 1 ♀, Bahia, Ilhéus, Santana River, trawl, St. 3 (14°50’ 35.8”S; 39°02’45.1”W), colls A. O. Almeida, J. T. A. Santos, N. R. Ferraz & C. S. Soares, 19.IX.2004 ( CCDB 4279 ) ; 1 ♂, 1 ♀, Bahia, Ilhéus, Santana River, trawl, St. 3 (14°50’ 35.8”S; 39°02’45.1”W), colls A. O. Almeida, J. T. A. Santos, N. R. Ferraz & C. S. Soares, 19.IX.2004 ( UESC 580 ) ; 1 ♂, 3 ♀♀, Bahia, Ilhéus, Cachoeira River, trawl, St. 4 (14°48’15.6”S; 39°04’22.3”W), colls A. O. Almeida, J. T. A.Santos & J. R. Luz, 24.IX.2004 ( UESC 592 ) ; 2 ♂♂, 5 ♀♀ (4 ovf), Bahia, Una, Comandatuba Island , Project Diversitas Neotropica, 26.V.1994 ( MZUSP 25486 ) ; 1 ♂, Bahia, Canavieiras, Patipe River, near bridge to Atalaia Island (15°40’34.8.15”S; 38°56’19.3”W), colls G. O. Soledade & A. C. C. Souza, 22.VI.2012, under rocks, salinity 15 ( UESC 1535 ) ; 1 ♀, São Paulo, Cananéia, near raft to Ilha Comprida (25°01’14.88”S; 47°55’25.01”W), colls T. Davanso & R. Pescinelli, 26.IX.2013 ( CCDB 4728 ) .

COMPARATIVE MATERIAL. — Alpheus heterochaelis : USA. 1 ♂, Georgia, Sapelo Island Sound, coll. M. Gray, 26.I.1962, 58- 86 ft ( USNM 181864 ) ; 1 ♀, Georgia, Sapelo Island, Doboy Sound , coll. M. Gray, 16.III.1961 ( USNM 181865 ) ; 1 ♀, Georgia, Sapelo Island, High Point , coll. M. Gray, 16.III.1961 ( USNM 181866 ) ; 1 ♂, Georgia, Sapelo Island, Doboy Sound , coll. M. Gray, 17.II.1966, 15- 20 ft ( USNM 181867 ) ; 1 ovf, Florida, Whitney Marine Lab , coll. I. Marin, 13.II.2010, saltwater pool, sand, under rocks, 0.2 m ( FLMNH UF Arthropoda 23208) ; 1 ♂, 2 ♀♀ (1 ovf), Florida, western side of Biscayne Bay at Cutler , south of Miami , coll. L. B. Holthuis, 15.IX.1960, in mangrove ( RMNH. Crus.D. 13039) ; 1 ♂, 1 ♀, Florida, Florida Keys , Key West, coll. A. L. Packard Jr. ( USNM 57635 ) ; 2 ♂♂, Florida, Marco Beach, south of Marco , coll. L. B. Holthuis, 12.IX.1960 ( RMNH. Crus.D. 17038) ; 1 ♂, 1 ♀, Mississippi, Dier Island ( USNM 64243 ) ; 2 ♂♂, Texas, Galveston Island, Offat’s Bayou, St. 8, coll. W. G. Hewatt, 24.III.1940 ( USNM 82116 ) ; 1 ♂, Texas, Ransom Island , coll. H. B. Paske, VII.1936 ( USNM 72186 ). Alpheus pontederiae : Venezuela. 1 ♂, north of Ma- racaibo, El Nazareth, coll. A. Godoy, collection year unknown ( OUMNH. ZC. 2011-06.010) ; 1 ♂, Orinoco delta, XI-5037, coll. G. Pereira, 2003, AA fcn 03-029 ( OUMNH. ZC. 2011-06.002) ; 1 ♀, Orinoco Delta , XI-5224, coll. G. Pereira, AA fcn 03-028 ( OUMNH. ZC. 2011-06.004) ; 2 ♂♂, 1 ♀, manglar la Rosita, colls J. Delgado & A. Godoy, 14.VI.1995 ( OUMNH. ZC. 2011-06.013) .

Surinam. 1 ♂, 1 ovf, Surinam River mouth, eastern shore, Braamspunt, on soft intertidal mud, coll. L. B. Holthuis, 05.IV.1957 ( RMNH.Crus.D.11461).

Brazil. Pará: 2 ♂♂, Baía do Sol, coll. C. Pantoja, I.1998 ( MZUSP 9680); 1 ♂, 4 ♀♀ (2 ovf), Marajó Island, Soure River, coll. Ehrhardt, 21.II.1923 ( SMF 8122); 3 ♂♂, 7 ♀♀, Marajó Island, Soure River, coll. Ehrhardt, XII.1923 ( SMF 8123); 4 ovf, Marajó Island, Soure River, coll. Ehrhardt, 1924 ( SMF 8130); 4 ovf, Marajó Island, Soure River, coll. Ehrhardt, 21.XI.1923 ( SMF 8136); 1 ♂, 1 ♀, Marajó Island, Soure River ( MFN 23280); 6 ♂♂, 11 ♀♀ (7 ovf), same data as the holotype of A. petronioi n. sp. ( UESC 1566); 2 ♂♂, 1 ♀, Pará, Salinópolis, estuary near Maçarico Beach (00°35’ 49.24”S; 47°20’35.36”W), coll. F. L. Carvalho, L. Pileggi, R. Robles & E. Souza-Carvalho, 15.XI.2012 ( CCDB 4438); Rio Grande do Norte: 1 ovf, Porto do Mangue, Conchas River estuary, St. 26, mangrove (05°04.039’S, 36°45.702’W), colls M. Tavares et al., 25.XI.2009 ( MZUSP 22634); Bahia: see material reported by Almeida et al. (2006; 2012); São Paulo: 4 ni, Cananéia, near raft to Ilha Comprida, coll. M. L. Christoffersen, 08.II.1976, under rocks ( MZUSP 22295).

Guinea. 2 ♂♂, 4 ♀♀, Conakry, coll. M. Dellais, 14.III.1953 (MNHN-Na-3301).

Sierra Leone. 4 ♂♂, 2 ovf, Sierra Leone River, coll. A. R. Longhurst, 25.XI.1954 ( RMNH. Crus.D.20179).

Benin. 1 ♀, Lac Nokoué, Awansouri, north of Cotonou, coll. H. Hoestlandt, 17.VII.1963 ( RMNH. Crus.D.20176).

Nigeria. 13 ♂♂, 13 ♀♀ (8 ovf), Niger Delta, between Brass and Port Harcourt, coll.H. J. G. Beets, V-VIII.1960 ( RMNH.Crus.D.15531).

Congo Brazaville. 5 ♂♂, 3 ♀♀, Pointe Noire, Lagune de Djeno , coll. M. Rossignol (MNHN-Na-3299) ; 1 ♂, Pointe Noire, Lagune de Djeno , coll. A. Stauch, V.1964 (MNHN-Na-3300) ; 1 ♂, 2 ♀♀, Pointe Noire, Lagune de Djeno , coll. A. Crosnier (MNHN-Na-3302) .

São Tomé. 1 ♂, São Tomé, St. 7, mangrove lagoon near Porto Alegre, coll. A. Anker, 05.II.2006, low tide, in mud among mangrove roots, debris (coconuts) and rocks (in burrows), AA fcn 06-154 ( OUMNH. ZC. 2011-06.008).

DISTRIBUTION. — Western Atlantic: Colombia, Venezuela and Brazil (Pará, Bahia and São Paulo).

DESCRIPTION. — Carapace smooth, with some dorsal pubescence ( Fig. 1A ), laterally not compressed; rostrum triangular, with acute tip almost reaching midlength of first segment of antennular peduncle; rostral carina sharply delimited between orbital hoods, slightly overreaching posterior margin of orbital hoods, not broadening posteriorly ( Fig. 1B ); adrostral furrows moderately deep, not abruptly delimited posteriorly ( Fig. 1B ); orbital hoods inflated dorsally, distally rounded, unarmed ( Fig. 1B ); pterygostomial angle rounded ( Fig. 1A, C ); cardiac notch well developed ( Fig. 1A ).

Abdominal somites smooth, with some dorsal pubescence on proximal somites ( Fig. 1A ); ventral and posterior margins of pleurae 1-4 broadly rounded and pleura 5 forming angle of approximately 90° with tip rounded; sixth pleura without articulated plate ( Fig. 1A ); protopod pleopods without spines; male pleopod 2 with appendix masculina slightly shorter than appendix interna; abdominal sternites without median processes; preanal plate with rounded tip. Telson broad, tapering distally, approximately 1.3 times as long as wide at base; lateral margins slightly sinuous; dorsal surface slightly convex, without median groove, with two pairs of spiniform setae, inserted at some distance from lateral margins, first pair slightly anterior to midlength, second pair well posterior to telson midlength ( Fig. 1I ); posterior margin broadly rounded, fringed with spinules (short spiniform setae) and long setae, posterolateral angle each with two pairs of spiniform setae, lateral spiniform seta approximately 1/2 length of mesial spiniform seta ( Fig. 1I ); anal tubercles well developed.

Eyes totally concealed in lateral, dorsal, and frontal views; cornea well developed, rounded ( Fig. 1 A-C). Ocellar beak protruding dorsally between eyes, apically rounded ( Fig. 1D ).

Antennular peduncle moderately slender ( Fig. 1B ). Stylocerite distally acute, reaching distal margin of first segment of antennular peduncle ( Fig. 1B ); ventromesial carina of first segment with tooth ending rounded, anterior margin straight, forming obtuse angle with posterior margin ( Fig. 1F ); visible part of first segment as long as wide; second segment longest, 1.9 times as long as wide and 1.3 times as long as visible part of first segment; third segment as long as wide, 0.5 times length of second segment ( Fig. 1B ); lateral antennular flagellum with row of aesthetascs starting at 16th segment ( Fig. 1E ). Antenna with basicerite bearing acute distolateral tooth ( Fig. 1C ); carpocerite moderately slender, reaching slightly beyond end of antennular peduncle ( Fig. 1C ); scaphocerite with lateral margin slightly concave; blade broad, reaching tip of antennular peduncle, separated from distolateral tooth by deep cleft running about 1/3 length of blade ( Fig. 1B ); distolateral tooth well developed, approximately 1/2 blade width at tip of scaphocerite, distinctly overreaching distal margin of blade, and slightly overreaching end of antennular peduncle and carpocerite ( Fig. 1B ).

Mouthparts not dissected, appearing typical for Alpheus in external view. Third maxilliped relatively slender, conspicuously longer than antennular peduncle and slightly overreaching carpocerite when extended; lateral plate ending distally on acute curved tooth and laterally rounded; antepenultimate segment not flattened or expanded, mesial margin distinct and thick, distodorsal portion not protruding ( Fig.1G, H ); penultimate segment about three times as long as wide, lateral margin smooth, with tufts of setae; last segment tapering distally, smooth, with several bands of setae; exopod reaching slightly beyond distal margin of antepenultimate segment ( Fig. 1G, H ). Major male cheliped with short, stout ischium ( Fig. 2A, C ); merus slightly excavated ventrally; ventrolateral and ventromesial margins straight, ending bluntly, unarmed ( Fig. 2A ); carpus short, cup-shaped ( Fig. 2C ); chela somewhat compressed; fingers closing in same plane as palm; palm with dorsal and ventral margins convex, with broad transverse grooves ( Fig. 2A, B ); dorsal grooves extending to mesial and lateral surfaces as deep depressions, latter extending posteriorly ( Fig. 2A, B ); dorsal shoulder rounded, not overhanging groove; ventral groove broad, oblique, deep, also extending mesially and laterally as well-delimited deep depressions, latter not extending posteriorly ( Fig. 2A, B ); ventral shoulder rounded, not protruding anteriorly ( Fig. 2A, B ); lateral and mesial surfaces mostly smooth; dorsal surface and shoulders with sparse long setae; linea impressa well marked on lateral surface ( Fig. 2A ); mesial surface ending bluntly distally ( Fig. 2B ); fingers compressed, longer than half palm length ( Fig. 2A, B ); pollex with tip curved upward, with shallow obtuse notch on cutting edge anterior to deep fossa ( Fig. 2D ); mesial surface surrounding fossa forming obtuse angle, fringed with rows of setae; lateral surface surrounding fossa slightly convex, with sparse long setae; dactylus reaching slightly beyond pollex, with rounded tip, cutting edge with long plunger, proximal height around. 0.7 times length of distolateral margin ( Fig. 2D ); adhesive disks conspicuous ( Fig. 2A, D ). Female major cheliped similar in shape, but proportionally smaller than that of male.

Minor male cheliped with ischium short and stout; merus proportionally longer and broader than that of major cheliped, slightly excavated ventrally; ventrolateral and ventromesial margins as in major cheliped ( Fig. 2F ); carpus short, cup-shaped ( Fig. 2F ); chela somewhat compressed laterally; palm with dorsal and ventral margins slightly convex, slightly sculptured, with very shallow dorsal depression extending to mesial and lateral surfaces, and with very shallow ventral groove, not markedly extending laterally or mesially ( Fig. 2E, F ); lateral and mesial surfaces mostly smooth; linea impressa well marked on lateral surface ( Fig. 2F ); dorsomesial angle of palm with blunt tooth ( Fig. 2E ); fingers as long as palm or slightly shorter, with conspicuous rows of balaeniceps setae, cutting edges sharp, tip curved ( Fig. 2E, F ); dactylus expanded laterally, with dorsal disk similar to adhesive disk of dactylus of major cheliped, and conspicuous carina on proximal region, ending at half dactylus length ( Fig. 2G ). Female minor cheliped more slender than that of males. Palm with lateral and mesial surfaces mostly smooth; linea impressa well marked on lateral surface ( Fig. 3A, B ); dorsal and ventral margins slightly convex; dorsal and ventral grooves absent; fingers as long as palm, without balaeniceps setae, cutting edges blade-like, tip curved ( Fig. 3A, B ); dactylus not expanded laterally, without proximal carina on dorsal margin, but with inconspicuously marked disk similar to that of male minor chela ( Fig. 3B ).

Second pereiopod slender, ischium and merus subequal in length; carpus five-segmented, first segment longest; segment ratio (proximal to distal) subequal to 2.4: 1.8: 1: 1: 1.3; chela simple, fingers as long as palm and bearing tufts of curved setae distally ( Fig. 3C ). Third pereiopod with ischium armed with spiniform seta on ventrolateral surface; merus longer than propodus, about five times as long as wide, distoventral margin unarmed; carpus unarmed, about 0.5 times merus length and 0.7 times propodus length ( Fig. 3D ); propodus with about 12 irregularly spaced strong spiniform setae of variable size along ventral margin, plus one distal pair of spiniform setae near dactylus; dactylus around 0.3 times propodus length, simple, slightly flattened and curved, acute distally ( Fig. 3E ). Fourth pereiopod similar in shape and length to third pereiopods, dactylus conical ( Fig. 3F ). Fifth pereiopod with ischium and merus unarmed; merus slender, about eight times as long as wide; carpus about 0.7 times merus length ( Fig. 3G ); propodus 1.3 times as long as carpus, with 6-8 spiniform setae along ventral margin plus one distal pair of spiniform setae near dactylus; distolateral surface with cleaning brush consisting of about 17 transverse rows of short setae; dactylus similar in shape to third and fourth pereiopods, proportionally slightly longer, corresponding to almost 0.3 times propodus length ( Fig. 3G ).

Uropods with bifid protopods, each lobe ending in acute tooth ( Fig. 1I ); endopod suboval, with posterior margin fringed with spinules (short spiniform setae) and long setae; exopod slightly longer than endopod ( Fig. 1I ); distolateral spiniform setae slender, distinctly shorter than posterior margin of exopods, not pigmented; exopodal diaeresis with two small lobes separated by median notch; distolateral tooth acute, approximately 1/2 length of or slightly shorter than distolateral spiniform seta ( Fig. 1I ). Gill formula typical for genus: pleurobranchs above first to fifth pereiopods; podobranch absent; one arthrobranch on third maxilliped; exopods on first to third maxillipeds; mastigobranchs (epipods) on coxae of third to fourth pereiopods; setobranchs on coxae of first to fifth pereiopods.

MORPHOLOGICAL VARIATION. — Sexual dimorphism between male and female major and minor chelae as described above. The notch on the cutting edge anterior to the fossa on the pollex of the major chela is in general shallow and obtuse, but the width and depth of this notch may vary (deeper and more acute). The sculpturing of the palm of the minor chela in males may vary from weak to moderate, and it is generally stronger in larger shrimp. The relative length of segments 1 (proximal) and 2 of the carpus of pereiopod 2 to the subequal segments 3 and 4 varies from 2.3-2.6: 1 and 1.6-1.9: 1, respectively. The number of spiniform setae on the propodus of pereiopods 3-5 may vary, especially on P5, as may also the number of transverse rows of short setae on the distolateral surface of the propodus of P5.

COLOR PATTERN (BASED ON ANALYSIS OF COLOR PHO- TOGRAPH OF FRESH SPECIMENS, Fig. 4C, D ). — Body of a small individual (CL 6.2 mm), from Canavieiras,

Bahia ( UESC 1535) semitransparent, with brownish chromatophores on palm of minor chela, carapace, abdomen, and uropods; major chela green, fingers darker than palm; depressions extending from transverse dorsal and ventral grooves whitish ( Fig. 4D ). Overall color pattern of a male-female pair photographed in the field shows the presence of dark-green to brownish dots on the chelae, carapace, abdomen and uropods ( Fig. 4C ).

ECOLOGY. — Pair-bonding species living in upper parts of estuaries. The material from the type locality was collected in the intertidal, under rocks, on mud and fine sand bottoms, at a salinity of 31. Also occurring under rocks at the type locality were the alpheids A. pontederiae and A. buckupi Almeida,Terossi, Araújo-Silva & Mantelatto, 2013 . The material from Canavieiras, Bahia, was also collected under rocks on mud in the intertidal zone, at a salinity of 15. Alpheus pontederiae was also recorded syntopically with the new species in that locality. No habitat information is available for the other collection sites.

Figures

FIG. 1. — Alpheus petronioi n. sp.: A-C, G, I, holotype, male (MZUSP 28314); D-F, H, paratype, male (UESC 1533): A, body, lateral view (appendages excluded,except uropods);B, frontal region and cephalic appendages,dorsal view;C, frontal region and cephalic appendages,lateral view;D, ocellar beak,lateral view;E, antennular flagella,proximal part with aesthetascs (arrow),ventral view;F, tooth (arrow) on ventromesial carina of first segment of antennular peduncle, lateral view; G, third maxilliped, lateral view; H, third maxilliped, mesial view;I, telson and right uropods,dorsal view (setae partially omitted).Scale bars: A, D, 2.5 mm;B, C, H, 2 mm; E, G, I, 1 mm; F, 0.5 mm.

FIG. 2. — Alpheus petronioi n. sp., holotype, male (MZUSP 28314): A, major cheliped, lateral view; B, same, mesial view; C, same, detail of ischium, merus and carpus, lateral view; D, detail of major chela,lateral view; E, minor cheliped,mesial view; F, same, lateral view; G, dactylus of minor cheliped, dorsal view. Scale bars: A, B, D-F, 2.5 mm; C, G, 1 mm.

FIG. 3. — Alpheus petronioi n. sp.: A, B, paratype, female (UESC 1533); C-F, holotype, male (MZUSP 28314): A, minor cheliped, mesial view; B, same, chela in dorsal view, merus and ischium in lateral view; C, second pereiopod, lateral view; D, third pereiopod, lateral view;E, same,dactylus and propodus,lateral view; F, fourth pereiopod,lateral view; G, fifth pereiopod,lateral view.Scale bars: A, C, F, G, 2 mm; B, 2.5 mm; D, E, 1 mm.

FIG. 4. — Alpheus petronioi n. sp.: A, B, views of the type locality, Mojuim River, São Caetano de Odivelas, Pará, Brazil, where the type material was obtained under rocks in the intertidal on a mud and fine sand bottom; C, male-female pair under rocks in the type locality (female on the left, male on the right); D, young male from Patipe River, Canavieiras, Bahia, Brazil (UESC 1535), dorsal view. Carapace lenght: D, 6.2 mm. Photographs: Alexandre O. Almeida.