Caprella equilibra Say, 1818

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 : 2524-2526

Caprella equilibra Say, 1818

( Figure 2 )

Caprella equilibra Say, 1818 ; Steinberg and Dougherty, 1957: 273–274, figs 1, 2. McCain, 1968: 25–30, figs 12, 13. McCain and Steinberg, 1970; Cavedini, 1982; Lazo-Wasem and Gable, 1987: 335–336, fig. 10. Krapp-Schickel, 1993: 782–783, fig. 533. Serejo, 1998; Ortiz et al., 2002, fig. 21. Foster, Thomas, et al., 2004: 162, 167–168, fig. 7. Diaz et al., 2005: 3–4, fig. 4. Winfield, Escobar-Briones, et al., 2007: 44, fig. 14. Guerra-García and Ros, 2012: 76–78, fig. 2.

Caprella aequilibra Mayer, 1882: 45 , pl. 1, fig. 7, pl. 2, figs 1–11, pl. 4, figs 20–25, pl. 5, figs 16–18. Chevreux and Fage, 1925: 455, fig. 433.

Caprella bermudia Kunkel, 1910: 108–110 , fig. 42. Lazo-Wasem and Gable, 1987: 335–336, fig. 10.

Material examined

Station 33, two males, six females, two juveniles (one male and one female from this station used for figures), BRTC 2–9489 .

Type locality

Charleston, South Carolina.

Distribution

Cosmopolitan ( McCain 1968; Krapp-Schickel 1993).

Records in the Gulf of Mexico

MEX: Tamaulipas and Veracruz continental shelf ( Escobar-Briones and Winfield 2003); Mexican ridges and Sigsbee abyssal plain at southwest ( Winfield et al. 2006). USA: Port Aransas ( Steinberg and Dougherty 1957); Port Isabel; Galveston; Grand Isle; Panama City ( McCain 1968); Louisiana Offshore ( Lewbel et al. 1987); Coast of Mississippi; St Andrew Bay (Foster, Thomas, et al. 2004); Port Aransas Offshore (present study).

Habitat

Caprella equilibra has been found on seagrasses, green and red algae, sponges, hydroids, alcyonarians, bryozoans, gorgonians, and ascidians ( McCain 1968; Gable and Lazo-Wasem 1987; Alarcón-Ortega et al. 2012). It has also been found in plankton samples, artificial substrata ( Lewbel et al. 1987; Takeuchi and Sawamoto 1998; present study) and on the carapace of the loggerhead sea turtle Caretta caretta ( Caine 1986) . The depth range reported is shallow water extending to 3700 m ( Winfield et al. 2006; Winfield and Escobar-Briones 2008; LeCroy et al. 2009).

Remarks

In the Gulf of Mexico, C. equilibra is similar to C. danilevskii because both lack a cephalic spine. However, these species can be easily separated because C. equilibra has a ventral spine between the bases of the second gnathopod, whereas C. danilevskii does not.

A recent morphological study of C. equilibra in southern Spain has revealed intraspecific variation in the female abdomen, even within the same population ( Guerra-García and Ros 2012). According to the diagnosis of the genus Caprella by McCain (1968), the abdomen of males is provided with a pair of uni- or bi-articulate appendages and a pair of lobes; females only have the pair of lobes and lack appendages. However, a few females of C. equilibra found in southern Spain were provided with abdominal appendages. The study provided evidence supporting the idea that the abdominal appendage is a polymorphic and symplesiomorphic character in Caprella and Metacaprella Mayer, 1903 (another genus with the same morphological variation), and that Metacaprella is not a valid genus ( Guerra-García and Ros 2012).

Figures

Figure 2. Caprella equilibra Say, 1818. Texas, USA; BRTC 2–9489. Scale bar: 1 mm.