Anacalliax argentinensis ( Biffar, 1971 )

Ferreira, Luciane Augusto de Azevedo & Pachelle, Paulo P. G., 2019, Discovery of the mud shrimp genus Anacalliax de Saint Laurent, 1973 (Decapoda: Callianassidae) in the Brazilian coast, Papéis Avulsos de Zoologia 59, pp. 1-3 : 1-3

Anacalliax argentinensis ( Biffar, 1971) Fig. 1 A‑G

Callianassa argentinensis Biffar, 1971: 229 , fig. 2.

Anacalliax argentinensis ( Biffar, 1971) ; Boschi, 1979: 137, tab. 1; Ferrari, 1981: 17, pl. III; Manning, 1987: 397; Manning & Felder, 1991: 787 (list), figs. 2, 3, 17; Boschi et al., 1992: 40, fig. 34; Sakai, 1999: 127; Tudge et al., 2000: 142 (list); Thatje, 2003: 119 (tab. 1); Sakai, 2005: 211; Sakai,2011: 343,fig.63A‑C; Spivak et al., 2019: 51.

Material examined: female, cl 4.5 mm, MZUSP 31510, Brazil, Rio de Janeiro, Angra dos Reis, station 331, 21.iii.1969, 22 meters depth.

Distribution: Brazil: Rio de Janeiro, Angra dos Reis (23°S) (present study). Uruguay: Rocha, Cerro Verde (33°S) ( Trinchin et al., 2014). Argentina: Provincia Buenos Aires, Riacho Jabalí, Bahía San Blas and Los Pocitos (40°S); Provincia Río Negro, Golfo San Matías (41°S); Provicia Santa Cruz, Río Deseado, in front of Isla del Rey (47°S) ( Biffar, 1971; Ferrari, 1981; Sakai, 1999, 2005, 2011).

Remarks: The morphological characters in the female from Brazil agree well with those described by Biffar (1971): (i) Rostral carina present ( Fig. 1A ); (ii) Mxp3 pediform, with ischium and merus narrow ( Fig. 1B ); (iii) P1 ischium with row of teeth on ventral margin ( Fig. 1C, E ); (iv) P1 fingers with cutting edges serrate ( Fig. 1D ); (v) telson subquadrate, shorter than uropods, with posterior margin medially concave ( Fig. 1F ).

In the original description, Biffar (1971) states that the Mxp3 ischium is unarmed, i.e., without a crista dentata (cf. Biffar, 1971: fig. 2g). Subsequent studies also depicted the species with a smooth Mxp3 ischium ( Ferrari, 1981: pl. III, fig. 7; Manning & Felder, 1991: fig. 3). However, the present specimen has a short crista dentata of3 minute teeth on the Mxp3 ischium ( Fig. 1B ). The chelipeds (P1) also have a different number of teeth on the ventral margin of merus and ischium compared to that reported for the species.In the present specimen, the merus of both major and minor P1 bear only 1 tooth (vs. 2‑3 teeth in Biffar, 1971), whilst the ischium has 8 teeth on major and 6 teeth on minor (vs. 5‑6 teeth on major and 4‑7 teeth on minor in Biffar, 1971). Ferrari (1981) also mentions a specimen with a single tooth on both P1 merus, but with no voucher reference to allow speculation. Nevertheless, the presence of a crista dentata on Mxp3 and the different armature on both P1 could be juvenile characters, thus changing during the ontogenetic development (note that Biffar (1971) ’s types range from 143 to 24 mm of total length,whilst our specimen is less than 10 mm long).

Lastly, the presence of spinules on the uropodal exopod is not mentioned in Biffar (1971) nor in Ferrari (1981) ( Fig. 1G ). However, it is likely that these spinules are present, but were overlooked in both previous studies due to the thick fringe of plumose setae on distal margin ( Fig. 1F ; see a similar case in Pachelle et al. (2017: 348) for Neocallichirus maryae Karasawa, 2004 ).

Figures

Figure 1.Anacalliaxargentinensis(Biffar,1971),female,cl4.5mm (MZUSP 31510).(A)Frontalmarginand cephalicappendages,dorsal view.(B)RightMxp3,mesial view.(C) Right major P1, lateral view.(D) Same, chela,lateral view. (E) Left minor P1, lateral view.(F) Sixth abdominal segment, uropods and telson, dorsal view. (G) Uropodal exopod,detail of the row of spinules on distal margin,plumose setaeomitted.Scale bars = 0.5 mm.