Morphology and function of the female reproductive system ofEbalia tumefacta(Decapoda, Brachyura, Leucosiidae)

Abstract

In this article, the morphology and function of the female reproductive organs of Ebalia tumefacta were investigated using histological methods. While the vagina conforms to the concave type, the study reveals a new orientation of seminal receptacle compartments. The seminal receptacle consists of two chambers, which are oriented in anterior-posterior direction. This is in contrast to the dorso-ventral orientation of seminal receptacle chambers in all other known brachyuran crabs. The anterior chamber is lined by cuticle, whereas the posterior chamber is covered with a holocrine glandular epithelium. The oviduct connection is located ventrally, close to the opening of the vagina. The oviduct orifice is characterized by a transition of the epithelium lining of the oviduct to the seminal receptacle holocrine glandular epithelium. Special features are muscle fibers, which are attached to the oviduct orifice and to the sternal cuticle as well. The muscle fibers can be found exactly at that point where the oviduct opens into the seminal receptacle and are secondly attached to the sternum beneath. This musculature is newly described for Eubrachyuran crabs. This musculature can be interpreted as an important feature in the fertilization and egg-laying process in relation to supporting and controling the inflow of eggs into the seminal receptacle lumen. These new discoveries were compared to the known pattern of an Eubrachyuran seminal receptacle.

Functional morphology of the female reproductive system of a crab with highly extensible seminal receptacles and extreme sperm storage capacity

“…In general terms, the histology of both the lined ventral cuticle and the dorsal extensible parts of the full SRs conform with previous descriptions in brachyuran crabs (Becker et al, ; Ewers‐Saucedo, Hayer, & Brandis, ; González‐Pisani et al, ; Hayer et al, ; McLay & Becker, ; Sal Moyano et al, ; Sant'Anna, Pinheiro, Mataqueiro, & Zara, ) with a soft secretory part, and a chitin lined part. In mature female D. crenulatus .…”

“…However, this knowledge is uneven and scarce considering that the the Brachyura holds about 6600 species; nearly the half of the total species of decapod crustaceans (De Grave et al, ). Moreover, new studies confirm there is much more morphological variation than previously thought (Hayer, Köhnk, Boretius, & Brandis, ; Hayer, Schubart, & Brandis, ). Typically the brachyuran SR has two distinct parts (Hartnoll, ; McLay & López Greco, ): (1) One of ectodermal origin, usually located ventrally and extending into a tube‐like structure, the vagina, connected with the exterior via an opening of the sternum called the vulva.…”

Morphology of the female reproductive system of three dorippid crabs (Crustacea: Decapoda: Brachyura: Dorippidae) and the role of accessory cuticle structures associated with seminal receptacles

“…), and Leucosiidae (Hayer et al. ), supports the possibility that a ventrally located oviduct orifice and a concave vagina might actually be plesiomorphic characters. The complete cuticle lining of the SR within dorippids is also problematic and its interpretation partly scenario based.…”

“…A corresponding process has previously been described in Ebalia tumefacta ( Montagu 1808) and D. sinica and referred to as “sinew” by Hayer et al. (, ). A recent study of the coxal gonopore in the podotreme brachyuran group Homoloidea has revealed surprising correspondences with the eubrachyuran concave vagina with respect to a muscular operculum and the crescent shape of the genital opening (Becker & Scholtz ).…”

“…According to the presented figures, the SR also seems to be predominantly cuticle‐lined in E. tumefacta (Hayer et al. ), Calappa pelii Herklots 1851, and Calappula saussurei ( Rathbun 1898) (Ewers‐Saucedo et al. ), but the authors do not provide further details.…”