Caprella suprapiscis, Galván-Villa, Cristian M. & Ayón-Parente, Manuel, 2015

Galván-Villa, Cristian M. & Ayón-Parente, Manuel, 2015, Caprella suprapiscis sp. nov. (Crustacea: Amphipoda: Caprellidae) from the Pacific coast of Mexico, Zootaxa 3956 (4), pp. 569-578 : 570-577

Caprella suprapiscis sp. nov.

( Figures 1–5 )

Type material. Holotype male. Bahía Chamela , Isla Cocinas. 19°32´46´´N, 105°06´28´´W, 6 m depth, 10 October 2013, collected from Scorpaena mystes , coll. Cristian M. Galván-Villa and Valentina Fernández-Del Valle ( LEMA- CCR 454A). Paratypes. Same locality. Same date. 1 female (LEMA-CCR454B); 1 male (LEMA-CCR454C); 1 female (LEMA-CCR454D); 1 male (LEMA-CCR457B). Bahía Chamela , Isla Pajarera. 19°33´44´´N, 105°06´42´´W, 6 m depth, 0 6 December 2013, 1 male and 1 female (EMU); 1 male and 1 female ( CNCR); 1 male and 1 female (LACM-CR); 1 male and 1 female ( USNM).

Additional material. Bahía Chamela , Isla Colorada. 19°32´23´´N, 105°05´31´´W, 6 m depth, 10 October 2103, 1 male, 3 females, and 1 juvenile (LEMA-CCR451); 5 m depth, 10 October 2013, 1 male and 1 female (LEMA-CCR452); 7 m depth, 12 November 2013, 40 males, 32 females, and 37 juveniles (LEMA-CCR456). Bahía Chamela , Isla Cocinas. 19°32´46´´N, 105°06´28´´W, 5 m depth, 10 October 2013, 1 female ( LEMA- CCR 453); 6 m depth, 10 October 2013, 27 males, 21 females, and 31 juveniles (LEMA-CCR454). Bahía Chamela , San Agustín. 19°32´8´´N, 105°05´15´´W, 5 m depth, 12 October 2013, 2 males (LEMA-CCR455). Bahía Chamela , Isla Pajarera. 19°33´44´´N, 105°06´42´´W, 6 m depth, 0 6 December 2013, 56 males, 24 females, and 12 juveniles (LEMA-CCR457A).

Type locality. Isla Cocinas, Bahía Chamela , Jalisco, Mexican Pacific.

Distribution in the area. The Bahía Chamela islands were declared a Natural Protected Area since 2002 with the category of Sanctuary. Eight islands (Pajarera, Cocinas, Mamut, Colorada, San Pedro, San Agustín, San Andrés, and Negrita) and four islets (Los Anegados, Novillos, Mosca, and Submarino) are included. So far Caprella suprapiscis sp. nov. has been collected in Cocinas, Colorada, San Agustín, and Pajarera islands ( Fig. 1 ).

Etymology. The species name suprapiscis is derived of the Latin supra (over) and piscis (fish), referring to the presence of the caprellids on the skin of Scorpaena mystes .

Description. Based on the male holotype (LEMA-CCR454A).

Body length. 6.1 mm.

Lateral view. Body dorsally slender without tubercles or spines. Head with a forward-pointing dorsal projection (shorter in females and juveniles), head and pereonite 1 partially fused, suture present. Pereonites 1–2 similar in length and larger than 3–6, pereonite 7 the shortest. Pereonite 5 with a small mid-dorsal projection ( Fig. 2 A, C, D).

Gills. Present on pereonites 3–4, elongate, length about 3.5 times width ( Fig. 2 A).

Antennae. Antenna 1 about half of the body length; peduncle scarcely setose; peduncular article 2 longest, 1.6 times length of article 1; peduncular articles 1–3 with numerous small granules and some short setae; flagellum composed of 15 articles. Antenna 2 about half length of antenna 1; peduncular articles carrying 12 pairs of long setae; flagellum 2-articulate with serrate setae ( Fig. 2 B, C).

Penes. Short, length about 1.5 times the width. Abdomen with a pair of 2-articulate appendages, bearing 5 setae on basal article and 2 on distal article; a pair of lateral lobes and a single dorsal lobe ( Fig. 3 D).

Mouthparts. Maxilliped inner plate with 2 teeth and 6 simple setae; outer plate with 5 robust and short setae and 13 simple marginal and submarginal setae; palp 4-articulate, setose; article 4 with rows of setulae on grasping margin ( Fig. 4 A). Maxilla 1 outer lobe with 7 forked spines; palp biarticulate; article 2, 4 times article 1, with 8 teeth distally, 5 robust subdistal and 5 lateral setae ( Fig. 4 B). Maxilla 2 inner lobe oval, outer lobe rectangular, about 2.4 times as long as the inner lobe ( Fig. 4 C). Upper lip symmetrically bilobed, short setae apically ( Fig. 4 D); lower lip with inner lobes well demarcated; inner and outer lobes with short setae ( Fig. 4 E). Mandibular molar process strong; incisor and lacinia mobilis 5 toothed; left mandible with 3 pectinated setae, right mandible with only 2 ( Fig. 4 F, G).

Gnathopods. Gnathopod 1 basis as long as ischium, merus, and carpus combined, with 4 long setae subdistally; 3 ventral setae on ischium; merus and carpus setose; propodus elongate, length about 2 times width; propodus palm with 2 proximal grasping spines, grasping margin serrate, with mixed long and short setae along the palm, two longitudinal rows of setae, one near grasping margin, another near dorsal margin, latter longer; dactylus slightly curved, grasping margin serrate, with few setae, one large tooth subdistally; middle outer surface with row of moderately strong teeth on distal third, becoming flattened scales posteriorly, middle upper outer surface with 5–6 longitudinal rows of flattened scales bearing short, marginal setae ( Fig. 5 A). Gnathopod 2 inserted near distal end of pereonite 2; basis about 1.7 times the length of pereonite 2 and 3/5 length of propodus, provided with a dorsal projection, dorsal margin finely setose; ischium subrectangular; merus with tuft of setae ventrally; carpus very reduced, subtriangular; propodus elongate, length about 3 times width, dorsal surface slightly convex and finely setose on dorsal and ventral margins with one proximal projection provided with a robust seta from 2/5 of proximal end; another projection in the middle, followed by “U” notch distally; dactylus falcate, setose on dorsal and lateral margins, with a proximal broad tooth followed by a smaller tooth; flexor margin with minute granules ( Fig. 5 B).

Pereopods. Pereopods 3 and 4 absent. Pereopods 5–7 increasing in length, scarcely setose; basis with a distal triangular projection; basis of pereopods 6 and 7 with small granules on dorsal margin; merus with a rounded projection and some setae; carpus subrectangular, nearly as long as merus, with setae at dorsal and ventral margins; propodus provided with a pair of grasping spines proximally; dactylus curved ( Fig. 6 ).

Paratype female. LEMA-CCR454B. Differs from male in the following characters: flagellum of antenna 1 with 12 articles ( Fig. 3 A); head with forward-pointing dorsal spine shorter than male; oostegites present. Gnathopod 2 inserted on the anterior half of pereonite 2, basis about half of pereonite 2 length; propodus length about 2 times width and 2.5 times longer than basis; dorsal surface of propodus convex with 3 setae; with only one anteriorly ventral projection provided with a robust bifid seta from 1/4 of proximal end; margin ventral with numerous robust bifid and single setae; mid-palmar projection followed by a minute sinus and a small triangular projection. Dactylus ventrally granulate ( Fig. 5 C). Pereonites 2 and 3 about the same length, longer than pereonites 4 and 5. Pereonites 3 and 4 with small tubercle on dorsal margin. Pereonite 5 with a pair of genital papillae. Abdomen without appendages, only lateral and dorsal lobes presents ( Fig. 3 B, C).

Color in life. Color differs according to the location of the specimens on the body surface of the fish, thus indicating a mimetic adaptation.

Remarks. Specimens of C. suprapiscis sp. nov. were collected from seven scorpionfishes ( Scorpaena mystes ) in coral and rocky reefs habitats in depths between 5 and 7 m. This is the first record of a caprellid associate with fishes in the eastern Pacific and the second worldwide ( Mori & Yamato 1993).

When compared to other species reported for the eastern Pacific, Caprella suprapiscis sp. nov. presents major resemblance with C. californica Stimpson, 1857 , C. mercedesae Hendrickx & Ayón-Parente, 2014 , and C. scaura Templeton, 1836 that also feature a sharp spine on the forehead. Besides, C. suprapiscis sp. nov. and C. californica have setose second gnathopods. Caprella suprapiscis sp. nov. is distinguished from C. californica by the shorter rostrum, fewer number of articles in antenna 1 (15 vs. 20), the maxilliped inner plate with 2 teeth and the outer plate with 5 teeth, in lieu of 3 teeth and only setae (no teeth), respectively, and maxilla 1 with article 2 shorter, ventral margin of gnathopod 1 serrated vs. unserrated, gnathopod 2 proportionally shorter in the relation lengthwide and shorter basis length, absence of a dorsal and a ventral projections in pereonite 2 in both males and females, and absence of a pair of mid-dorsal projections on pereopods 6 and 7. The new species C. suprapiscis is also clearly smaller than C. californica . The largest male of C. suprapiscis was 9 mm, whereas C. californica maximum length is 24.23 mm ( Takeuchi & Oyamada 2013).

Caprella suprapiscis sp. nov. can be differenced of C. mercedesae by the position of the rostral spine, behind the eyes in the former vs. anterior to the eyes in the later; the dactyl of gnathopod 1 ends in a single tooth in C. suprapiscis but bears 4 large teeth in C. mercedesae ; in males, gnathopod 2 is set at the posterior margin of pereonite 2 vs. at mid-length in C. mercedesae , the carpus is unarmed in the new species and its ventral margin is serrate in C. mercedesae ; the dactyl is smooth in the new species vs. finely crenulated dorsally in C. mercedesae , pereonites 5 to 7 lack spines in C. suprapiscis sp. nov. but bear spines on the posterior margin in C. mercedesae . Finally, Caprella suprapiscis sp. nov. can be distinguished from C. scaura in which the forehead spine is located further from the eyes (Templeton, 1836, fig. 6a, b) than in C. suprapiscis ; also, the basis of gnathopod 2 is proportionally larger in C. scaura than in C. suprapiscis , being as long as pereonite 2 and longer than propodus in the former (Templeton, 1836, fig. 6a) and it is shorter than pereonite 2 and also shorter than the propodus in the later ( Fig. 2 A, C).

Figures

FIGURE 1. Map of Bahía Chamela with sampling locations (black circles) where specimens of Scorpaena mystes Jordan and Starks, 1895 were collected.

FIGURE 2. Caprella suprapiscis sp. nov. Holotype male, TL 6.1 mm (LEMA-CCR 454 A), A) lateral view, B) antenna 2. Paratype male, TL 9 mm (LEMA-CCR 457 B), C) lateral view, D) pereonites 5 – 7 detail. Scale bars, A, C = 1 mm; B, D = 0.5 mm.

FIGURE 3. Caprella suprapiscis sp. nov. Paratype female, TL 4.8 mm (LEMA-CCR 454 B), A) lateral view, B) abdomen, dorsal view, C) abdomen, ventral view. Holotype male, D) abdomen, ventral view. Scale bars, A = 1 mm; B, C, D = 0.5 mm.

FIGURE 4. Caprella suprapiscis sp. nov. Paratype male, TL 7.7 mm (LEMA-CCR 454 C), A) maxilliped, B) maxilla 1, C) maxilla 2, D) upper lip, E) lower lip, F) left mandible, G) right mandible. Scale bars = 0.1 mm.

FIGURE 5. Caprella suprapiscis sp. nov. Holotype male, TL 6.1 mm (LEMA-CCR 454 A), A) gnathopod 1, lateral view, B) gnathopod 2, lateral view. Paratype female, TL 4.8 mm (LEMA-CCR 454 B), C) gnathopod 2, lateral view. Scale bars, A, B = 0.5 mm; C = 0.2 mm.

FIGURE 6. Caprella suprapiscis sp. nov. Holotype male, TL 6.1 mm (LEMA-CCR 454 A), A) pereopod 5, B) pereopod 6, C) pereopod 7, lateral view. Scale bar = 0.5 mm.