Metaprotella hummelincki McCain, 1968

Paz-Ríos, Carlos E., Guerra-García, José M. & Ardisson, Pedro-Luis, 2014, REVIEW ARTICLE Caprellids (Crustacea: Amphipoda) from the Gulf of Mexico, with observations on Deutella mayeri, redescription of Metaprotella hummelincki, a taxonomic key and zoogeographical comments, Journal of Natural History 48 (41 - 42), pp. 2517-2578 : 2543-2549

Metaprotella hummelincki McCain, 1968

( Figures 12–15 )

Metaprotella spec. Mayer, 1903: 43 .

Metaprotella hummelincki McCain, 1968: 78–82 , figs 39, 40. Ortiz et al., 2002, fig. 36.

Material examined

Station 10, 29 males (six males from this station used for figures), 52 females (34 ovigerous; one female from this station used for figures), 17 September 2007, CYMX- 14- CY . Station 21, one ovigerous female, 30 August 2010, CYMX-44- CY . Station 22, two females, two juveniles, 21 July 2010, CYMX-38- CY ; two juveniles, 28 September 2010, CYMX-45- CY . Station 23, one ovigerous female, one juvenile, 21 July 2010, CYMX-40- CY . Station 24, one juvenile, two ovigerous females, 16 April 2010, CYMX-26- CY . Station 26, one ovigerous female, 19 June 2010, CYMX-33- CY ; one ovigerous female, 26 July 2010, CYMX-42- CY . Station 27, four males (one male from this station used for figures), five ovigerous females, CYMX-35- CY . Station 28, three males, five females, three juveniles, 8 July 2013, CYMX-48- CY .

Redescription

Mature male, body length 8.5 mm, CYMX-35-CY. Body with tubercles on the head, pereonites 2–4, and the proximal lateral surface of pereonite 5; suture between head and pereonite 1 present; eye distinctive; gills on pereonite 3 and 4, oval; pereopods 3 and 4 one article approximately one-quarter length of gills.

Antenna 1 longer than total body length, peduncle longer than flagellum by 10%, peduncle article 1 with five dorsal plumose setae, flagellum with 15 articles, longer than antenna 2. Antenna 2 longer than head to end of pereonite 2, peduncle article 2 with two dorsal spines, flagellum with two articles.

Upper lip symmetrically bilobed; each lobe carrying a distal row of dense setulae. Mandibular molar process strong with a large tooth on incisor side; left mandible with incisor and lacinia mobilis divided into five teeth followed by three pectinate setae; right mandible with incisor divided into five teeth followed by a lacinia mobilis toothed but not distinctly 5-toothed, and 3 pectinate setae; palp with three articles, article 3 with 3–4 setae, article 3 with setal formula 1–12–1–1 on left mandible and 1– 13–2–1 on right one. Inner lobes of the lower lip well demarcated with many dense setules close to margin; outer lobes extend backwards, dense setules around inner margin. Maxilla 1 outer lobe carrying seven spines (4 bifurcate, two serrate, one smooth); distal article of palp with four spines and six setae. Outer and inner lobes of the maxilla two carrying eight setae, three of these very short and one plumose on the inner lobe. Maxilliped, inner plate rectangular apically truncate, with five plumose and one non-plumose apical setae, and one tooth on mediodistal margin; outer plate with 1 apical seta and two setae in notch at midlength of medial margin, medial and lateral margin setulose; article 3 of the palp distally expanded.

Gnathopod 1, dactylus not quite extended to carpus, with single row of cuticular spines on inferior margin and one on a submarginal ridge, propodus inferior margin with evenly spaced cuticular spines decreasing in size distally, carpus with rounded setose lobe on ventral surface. Gnathopod 2 dactylus decreasing 50% in width medially, 80% as long as propodus; propodus with one proximal grasping spine, inferior margin with 7 small spines, one poison tooth on proximal projection, and one large median excavation; palm densely setose.

Pereopods 3–4 one article with 5–6 apical setae, approximately one-quarter length of gills; pereopods 5–6 absent; pereopod 7 located posteriorly on pereonite 7, 6- articulate, propodus with a pair of proximal grasping spines.

Abdomen with a pair of appendages bearing fringe of setae and papillae at tip and with distinct pair of lobes bearing single seta.

Mature female, body length 6.9 mm, CYMX-14-CY. Body as in male. Antenna 1 longer than 0.77 total body length, peduncle shorter than flagellum, flagellum with 14 articles, longer than antenna 2. Antenna 2 longer than peduncle of antenna 1, longer than head to end of pereonite 2, flagellum with two articles. Mouthparts as male, except by outer lobe of maxilliped with two apical setae. Gnathopod 1 similar to male. Propodus of gnathopod 2 almost as long as basis, with proximal grasping spine, palm with notch. Gills and pereopods as in male. Abdomen with pair of lobes, each with 1 seta.

Ontogenetic development

The number of articles in the flagellum of antenna 1 (not figured) increases allometrically; it increases from 4 in the first stages of development to 15 in the final stage. Antenna 2 has two articles and this character is constant and consistent for the genus. The tubercle sizes proportionally increase with body length, hence larger specimens bear larger tubercles. Generally tubercles were larger in the female specimens observed than in the males. The aspect of male gnathopod 2 changes considerably during development. Initially, the propodus is wider, scarcely setose, with a shallow distal notch, and a small poison tooth. The distal notch and poison tooth are visible at the same time as several small teeth appear on the proximal margin of the palm. And finally, for very large specimens the propodus becomes elongated (longer than wider), densely setose, with a wide medial notch, and a large poison tooth located at the proximal end of the palm.

Type locality

La Parguera, Puerto Rico .

Distribution

It is the only member of the genus Metaprotella occurring in the western Atlantic: Gulf of Mexico (Winfield, Abarca-Arenas, et al. 2007) and Caribbean Sea ( McCain 1968; Ortiz et al. 2009).

Records in the Gulf of Mexico

MEX: Veracruz Coral Reef System (Winfield, Abarca-Arenas, et al. 2007); Celestun; Celestun Offshore; Sisal Offshore; Telchac Offshore (present study).

Habitat

This species has been found on Thallassia sp. in the Caribbean Sea ( McCain 1968), on fouling panels among coral reefs (Winfield, Abarca-Arenas, et al. 2007), on muddy sediment, and sandy bottoms from coral reef areas on southeastern Gulf of Mexico (present study). The depth range reported is 1–29 m ( McCain 1968).

Remarks

Metaprotella hummelincki was originally described and illustrated from La Parguera, Puerto Rico by McCain (1968). After description, the species was illustrated in the pictorial guide by Ortiz et al. (2002). In both cases, illustrations resemble immature stages in males and females, lacking traits present in the newly specimens found in this study. Therefore, M. hummelincki is redescribed here in detail based on specimens found from the north coast of Yucatan Peninsula, SE Gulf of Mexico. These specimens represent mature stage in males with tubercles on the head, inner plate of maxilliped with 1 tooth on mediodistal margin, gnathopod 2 dactylus decreasing in width medially, and gnathopod 2 propodus with a large median excavation and a large poison tooth on proximal projection. In females, the mature stage is represented by specimens with tubercles on the head and palm with notch on propodus of gnathopod 2.

All species of the genus Metaprotella have spiny bodies or at least a cephalic spine ( McCain 1968; Larsen 1997; Guerra-García 2002a, 2003c; Takeuchi and Lowry 2007; Lim and Takeuchi 2012; Momtazi and Sari 2013), with the exception of Metaprotella problematica Mayer, 1890 which bears one forward pointing spine laterally on pereonite 3, Metaprotella mauritiensis Guerra-García, 2003c with head and body smooth, and M. hummelincki with tubercles on the head, at the insertion of gnathopod 2, pereonites 3–4 and at the proximal lateral surface of pereonite 5.

Male specimens of M. hummelincki are similar to male specimens of Metaprotella unguja Larsen, 1997 by the shape of gnathopod 2, but differ by the tubercles and the abdomen. Female specimens of M. hummelincki differ from female specimens of M. unguja by the presence of tubercles, instead of paired dorsal spines above the insertion of gnathopod 2 otherwise smooth.

Figures

Figure 12. Metaprotella hummelincki McCain, 1968. Yucatan, Mexico; male, CYMX-35-CY; female, CYMX-14-CY. Scale bar: 1 mm.

Figure 13. Metaprotella hummelincki McCain, 1968. Yucatan, Mexico; male, CYMX-35-CY. Scale bar: 0.1 mm.

Figure 14. Metaprotella hummelincki McCain, 1968. Yucatan, Mexico; male, CYMX-35-CY; female, CYMX-14-CY. Scale bars for P3 and AbDv: 0.1 mm; scale bars for Hd, Gn1 and Gn1 of female: 0.3 mm; scale bars for Gn2, Gn2 of female, P7 and AbLv: 0.5 mm.

Figure 15. Metaprotella hummelincki McCain, 1968. Yucatan, Mexico; males, CYMX-14-CY. Scale bars for Hd and Gn2: 0.3 mm; scale bar for Bd: 1 mm.