Callichirus garthiis a valid species, distinct fromC. seilacheri(Decapoda: Axiidea: Callianassidae)

Abstract

Callichirus garthi from the southeastern Pacific has long been considered as a junior synonym of Callichirus seilacheri from the eastern tropical Pacific. The present study is based on a detailed comparison between both taxa collected along the coast of Chile and the Pacific coast of Central America, including type material of C. garthi and topotypic material of C. garthi and C. seilacheri. This reveals that C. garthi is a valid species, with a suite of morphological features that allow it to be separated from C. seilacheri. Callichirus garthi can primarily be distinguished from C. seilacheri by closely set eyestalks; the proximal margin of the terminal antennular segment exceeding the proximal margin of the last antennal segment with the dorsal margins of both the basal and intermediate antennular segment setose; the merus of the larger cheliped armed with a rough semicircular lobe over the anterior ventral margin and the ischium curved downwards without ornamentation on the ventral margin. On the basis of the present study, we therefore resurrect C. garthi as a valid species for the Chilean and Peruvian populations.

An Update on Reproduction in Ghost Shrimps (Decapoda: Axiidea) and Mud Lobsters (Decapoda: Gebiidea)

“…The location of the male and female sexual openings in Axiidea and Gebiidea is similar to described universally for the reptant decapods [57]. Males possess prominent gonopores on the ventral coxal segment of the fifth pereiopod, whereas females have oval gonopores on the ventral coxal segment of the third pereiopod [40,58,59] ( Figure 3A).…”

“…The first pleopod is absent in most males of Axianassidae, Laomediidae, Strahlaxiidae, and Upogebiidae and in numerous Callianassidae [15,16,66,67]. When present, the male first pleopod is uniramous and can be unsegmented as in Thalassina [68], bisegmented as in Callichirus [58], or composed of four articles as in Ctenocheles [69].…”

“…Female first pleopod is present in all females of Axiidea and Gebiidea [15]. It is uniramous and consists of one article in Axianassidae, two articles in most families, or three articles in Callianassidae, with the distal part sometimes appearing as a shovel (Callianassidae) or flagellum (Laomediidae, Callianideidae) [58,59,66,73]. Depending upon species, sometimes the first two pairs or all female pleopods are used for carrying the eggs during the incubation of embryos [55,[74][75][76].…”

Relative growth, sexual maturity and handedness in the ghost shrimp <em>Callichirus major</em> (Decapoda: Callianassidae) from the southwestern Atlantic

“…* Currently accepted as Callichirus garthi; ** Positive allometric growth informed for each sex, but not for each development phase. Heterochelous males were common in C. major (87%) from Gonzaga beach, as occurs with other species of the genus Callichirus (Manning and Felder 1986, Hernáez and Wehrtmann 2007, Hernáez et al 2015. On the other hand, most females of C. major were homochelous (59.3%).…”

“…Subsequently, Alves-Júnior et al (2014) reported a positive allometry through this species's ontogeny with this same relationship, confirming a higher chelar growth in males than in females for a population of C. major from Recife, in the northeastern region of Brazil, a fact explained by the thermal regime promoted by latitudinal influence. Both of these studies considered the growth of a chelar article that reaches a smaller size than the carpus, a noteworthy characteristic in species of the genus Callichirus Stimpson, 1866 (Manning and Felder 1986, Hernáez et al 2015, Hernáez and João 2018. Another recent contribution by Alves-Júnior et al (2018) indicated that the whole cheliped in C. major grows at a higher rate than the carapace, especially for males.…”