Caprella mendax Mayer, 1903

Sánchez-Moyano, J. E., García-Asencio, I. & Guerra-García, J. M., 2014, Littoral caprellids (Crustacea: Amphipoda) from the Mexican Central Pacific coast, with the description of four new species, Journal of Natural History 49 (1), pp. 77-127 : 89-93

Caprella mendax Mayer, 1903

( Figures 6–8 )

Caprella mendax Mayer 1903 ; Laubitz 1970.

Caprella equilibra: Dougherty and Steinberg 1953 .

Material examined

St1: 67 males, 56 females, 54 juveniles; St2: 11 males, 5 females, 6 juveniles; St4: 6 males.

Remarks

Typical features of the species are present such as body smooth, a small projection at the base of each gnathopod 2 or length of pereonite 5 larger than pereonite 4. Mouthparts typical of genus. Antenna 1 longer than pereonites 1, 2 and 3 with 16 articles in flagellum. Gnathopod 2 inserted posteriorly on pereonite 2; basis shorter than half pereonite 2 and one-quarter of total appendage length, with an anterior denticulate carina; propodus twice as long as broad, palm with one proximal grasping spine, and poison tooth and triangular projection distally. Pereopods 5, 6 and 7 increasing in length, with propodus with proximal grasping spines and concave palm. Abdomen typical of genus.

However, our specimens showed characteristics of both Caprella mendax and C. equilibra ( Table 2), although, according to Mayer (1903) and Laubitz (1970), because the main differences are based on the structure of the second gnathopod and the length of pereonite 5 being greater than pereonite 4 in the first species, we have tentatively assigned them to C. mendax .

Laubitz (1970) found specimens up to 16.4 and 11.2 mm in length for males and females, respectively, but the largest male and female lengths in our study were 9.3 and 7 mm.

One of the more distinctive features in both C. mendax and C. equilibra is the presence of a ventral acute projection between gnathopods 2, which is absent in the material studied. McCain (1968) reported a variant of C. equilibra , associated with the gorgonian Leptogorgia , along the coast of Virginia, North Carolina and South Carolina in which the spine was reduced or absent and the body not quite as stout as in the typical form. Our material was also found on gorgonians ( Leptogorgia rigida , Leptogorgia peruviana , Muricea sp. and Pacifigorgia sp.). In agreement with McCain (1968), this substrate may have some relation to the reduction of the spine and stoutness of the body. Further studies would be necessary to clarify this question and to elucidate the potential synonymy between C. equilibra and C. mendax .

Habitat

Caprella mendax occurs predominately in the intertidal zone and shallow waters ( Watling and Carlton 2007), although it has also been found up to 80 m deep ( Martin 1977). It lives on a great variety of substrates such as seaweeds ( Hammer and Zimmerman 1979) or hydroids ( Dougherty and Steinberg 1953). In our study, C. mendax was more abundant in shallow waters (up to 5 m) on seaweeds ( Zonaria cf. farlowii ) with epiphytic hydroids and on gorgonians ( Leptogorgia rigida , Leptogorgia peruviana , Muricea sp. and Pacifigorgia sp.).

Distribution

Type locality. California. Other records: Dillon Beach, Moss Beach and Pacific Grove-Monterey Bay, California ( Dougherty and Steinberg 1953); Vancouver Island and Hecate Strait (British Columbia), San Juan Islands (Washington) ( Laubitz 1970); off Humboldt Bay ( Martin 1977); Mazatlán is the most southerly record of C. mendax if validity of species is confirmed.

Figures

Figure 6. Caprella mendax Mayer, 1903. Lateral view. Scale bar: 1 mm.

Figure 7. Caprella mendax Mayer, 1903. Male mouthparts. Scale bar x (Mx1, Mx2, LMd, RMd, Mxp) and y (UL, LL): 0.1 mm.

Figure 8. Caprella mendax Mayer, 1903. Male gnathopod 1 and 2, pereopods 5–7, abdomen. Female abdomen. Scale bar: x (Gn1, Gn2): 0.3 mm; y (P5-7): 0.3 mm; z (Ad): 0.1 mm.