Acanthephyra acutifrons Bate, 1888

Cardoso, Irene & Contents, Paulo Young Table Of, 2005, Deep-sea Oplophoridae (Crustacea Caridea) from the southwestern Brazil, Zootaxa 1031 (1), pp. 1-76 : 8-14

Acanthephyra acutifrons Bate, 1888

( Figs 3–7 )

Acanthephyra acutifrons Bate, 1888: 749 , pl. 126: fig. 3; Chace, 1940: 146, fig. 23; 1986: 10, figs 2b, 4b, 5b.

Material examined: Revizee Program: E­0520, 13°21’S, 38°16’W, 2137 m, 1 male (48.5mm), MNRJ 14843 ; E­0519, 13°19’S, 38°19’W, 1730m, 2 males (45, 49mm), MNRJ 14848 ; E­0552, 21°07’S, 39° 46’W, 1694m, 1 male (51mm), MNRJ 18882 .

Diagnosis: Carapace with rostrum short, reaching 2/3 of scaphocerite, ventral margin with one tooth; antennal spine absent; branchiostegal spine present, without distinct carina. Abdomen dorsally carinate on all somites; somites 3 to 6 with posteromesial tooth; the one of somite 3 distinctly strong. Male pleopod 1 with endopod rounded, lateral margins with densely plumose setae, distal lobe with numerous hook setae on distal portion. Male pleopod 2 appendix interna, about 3/4 as long as appendix masculina, with numerous densely plumose setae on lateral margins, distal portion slightly triangular, with hook setae. Appendix masculina with strong acute simple setae on distal and lateral margins.

Description: Eyestalk with an ocellus on superior distal portion ( Fig. 3B ). Carapace with rostrum 1/3 length of carapace, reaching 2/3 of scaphocerite, ventral margin oblique, with one tooth, dorsal margin serrate, with nine­ten denticles; dorsal margin carinate throughout entire length; antennal spine absent; branchiostegal spine present, without distinct carina; supraorbital and pterygostomian spine absent; cervical groove absent; suprabranchial carina and hepatic groove present ( Fig. 3A ). Stylocerite elongate, reaching 3/4 of first antennular peduncle article, with acute apex and simple setae ( Fig. 3C ). Scaphocerite with acute apex, and several simple setae on inner margin ( Fig. 3D ). Mandible with palp three­articulated, incisor process with about ten to 12 teeth, molar process triangular, with a row of small stout setae ( Figs. 4A, B ). Maxilla 1 with two endites, distal endite with numerous stout serrate setae on inner margin; basal endite leaf like, with pectinate and pappose setae on inner margin; palp with several pectinate setae on rounded apex, and four stout setae on a protuberance ( Fig. 4C ). Maxilla 2 with two endites, distal bilobed, basal lobe with long, stout, pectinate setae on inner margin, distal lobe with pappose­pectinate setae on inner margin; basal endite rounded, with densely plumose setae on inner margin; endopod half length of endites, with simple setae on apex; scaphognathite with densely plumose setae on all margins ( Fig. 4D ). Maxilliped 1, endite with pappose­pectinate setae on inner margin; endopod three­articulated, as long as endites, with several pappose setae on apex and inner margin; exopodal lobe with densely plumose setae in all margins ( Fig. 4E ). Maxilliped 2 endopod with elongate ischium and merus with pappose setae on inner margin; carpus short; propod rounded with pappose and pectinate setae on distal margin, and long, stout, pectinate setae on inner margin; dactyl with long, stout setae on inner margin; elongate exopod, with densely plumose setae on all margins ( Fig. 4F ). Maxilliped 3 slender and elongate, propod­dactyl with stout setae in distal portion; exopod elongate, with densely plumose setae on all margins ( Fig. 4G ). Pereopods 1 and 2 chelate. Pereopod 3, ischium with nine stout setae on inner margin; merus with 11 stout setae on inner margin. Pereopod 4, ischium with two stout setae on inner margin; merus with 11 stout setae and four small stout setae on inner margin. Pereopod 5, ischium unarmed; merus with seven stout setae on inner margin ( Fig. 3A ). E pipods with mesial teeth, present on pereopods 1 to 3 ( Fig. 5A, B ). Abdomen dorsally carinate on all somites; somites 3 to 6 with posteromesial tooth; one of somite 3 distinctly strong; somite 6 at least 1 ½ times as long as height ( Fig. 3A ). Male pleopod 1 with endopod rounded, with densely plumose setae on lateral margin, and a distal lobe with numerous hook setae ( Fig. 5C ). Male pleopod 2 with slender appendix masculina, with numerous strong acute simple setae on distal and lateral margins; appendix interna 2/3 length of appendix masculina, with numerous plumose setae on lateral margins, apex slightly triangular with numerous hook setae ( Fig. 5D ). Exopod of uropod with uncomplete diaresis, and one distal spine on outer margin ( Fig. 6A ). Telson sulcate in dorsal midline, with about six pairs of dorsolateral stout setae, three pairs of distal setae, and one median setae ( Fig. 6B ).

Distribution: Western Atlantic: Mexico (Gulf of Mexico), Bahamas, Brazil (Bahia, Espírito Santo). Indian and Pacific: West Indian Ocean, Madagascar, Philippines, Indonesia (Sumatra), Australia. Adults probably live in depths between 650 and 2400 m ( Chace 1986; Crosnier 1987; Kensley 1987).

Remarks: This species occurs in the Indian, Pacific and Atlantic oceans, and has never been recorded before from Brazilian waters ( Fig. 7 ).

The genus Acanthephyra comprises 30 species, 11 of them occurring in the Western Atlantic Ocean. Of these 11 species, only two species ( A. gracilipes Chace, 1940 and A stylorostratis ( Bate, 1888)) have carapaces with a longitudinal ridge or carina on posterior half of the lateral surface, which is distinct from A. acutifrons that does not have a carina on the posterior half of the carapace lateral surface. Acanthephyra acutifrons and A. eximia Smith, 1884 . have the carapace dorsally carinate on entire length. Acanthephyra acutifrons differs from A. eximia by the short rostrum, not reaching the end of the scaphocerite, in the carapace length (45–51 mm), and by the abdominal somite 1 with a dorsal carina.

Acanthephyra acutifrons , A. eximia , A. quadrispinosa Kemp, 1939 and A. stylorostratis occur from Brazilian waters. Acanthephyra acutifrons differs from A. quadrispinosa by the carapace with dorsal carina in entire length, the rostrum short with only one ventral tooth and the abdominal somite 1 with dorsal carina. Acanthephyra acutifrons differs from A. stylorostratis in the rostrum shape, in the absence of the branchiostegal groove and by a larger carapace length ( Table 1).

The material examined herein agrees mostly with the descriptions of Bate (1888) and Chace (1940, 1986). The telson of the specimens examined present six pairs of dorsolateral stout setae, only one specimen having seven stout setae in right side of telson ( Fig. 7B ) and three pairs of distal setae were observed. Bate (1888) observed three or four and Chace (1940, 1986) observed five or six dorsolateral stout setae on telson of A. acutifrons . Furthermore, Bate (1888) observed four pairs of distal setae on telson.

Figures

FIGURE 3 — Acanthephyra acutifrons Bate, 1888, male, MNRJ 14848 (carapace length 45mm); A, lateral view; B, ocular peduncle and cornea, lateral view; C, right antennule, dorsal view; D, right scaphocerite, dorsal view (brs, branchiostegal spine; hg, hepatic groove; sbrc, suprabranchial carina; st, stylocerite).

FIGURE 4 — Acanthephyra acutifrons Bate, 1888, male, MNRJ 14848; A, left mandible, dorsal view; B, right mandible, dorsal view; C, left maxilla 1, dorsal view; D, left maxilla 2, dorsal view; E, left maxilliped 1, dorsal view; F, left maxilliped 2, dorsal view; G, left maxilliped 3, dorsal view.

FIGURE 5 — Acanthephyra acutifrons Bate, 1888, male, MNRJ 14848; A, epipod of right second pereopod, lateral view; B, epipod of left second pereopod, lateral view; C. endopod of right first pleopod, lateral view; D, appendix interna and masculina from right second pleopod, lateral view (ai — appendix interna; am — appendix masculina).

FIGURE 6 — Acanthephyra acutifrons Bate, 1888, male, MNRJ 14848; telson and uropods, dorsal view.

FIGURE 7 — Geographic distribution of Acanthephyra acutifrons Bate, 1888.