Observações morfológicas no camarão-fantasma Callichirus seilacheri (Bott, 1955) (Decapoda, Callianassidae)

Abstract

Callichirus seilacheri (Bott, 1955) is considered one of the most common ghost shrimps in the intertidal zone of sandy beaches along the eastern tropical Pacific. The present study provides new observations on the morphology of C. seilacheri, based on the revision of abundant material collected along the Pacific coast of Central America, including specimens from the type locality (Playa Los Blancos, El Salvador) of this species. The new features of C. seilacheri include: carapace with low triangular rostrum, without setae on tip; pereiopod 1 highly dissimilar in adult males, but not in females and juveniles of both sexes; first pleopod sexually dimorphic; females with oval gonopores, each one of them on the ventral coxal segment of the third pereiopod, and extra genital pores on the ventral coxal segment of the fifth pereiopod, these latter non-functional (non connected with the ovaries). Apparently, the presence of extra gonopores in females of C. seilacheri is a vestigial character shared with other representatives of the same genus.

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).…”

“…Secreting epithelium of the vas deferens is responsible for forming the gelatinous spermatophoric mass [61], as observed in other decapods [62]. Female sexual system is composed of paired orange or dark red ovaries (depending upon developmental stage), one ovary shorter than another, both visible through pleonal region and a pair of short and translucent oviducts linking the ovary to gonopore [59,60] ( Figure 3C). Seminal receptacle or spermathecae have not been described for any Axiidea and Gebiidea, despite attempts to find them [63].…”

“…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].…”

“…In the intertidal ghost shrimp Callichirus seilacheri (Bott, 1955), the burrow is individually inhabited by one male or a female (Figure 2A), and adult male develops hypertrophied chelipeds which is a potential evidence of intense male-to-male competition for sexual partners and therefore an indirect evidence of polygamy [98]. In a study conducted in Callichirus islagrande (Schmitt, 1935), an intertidal species in that males possess highly developed chelipeds [59], the egg mass of females is fertilized by multiple males which denotes polyandry [63].…”