The male copulatory system of european pea crabs (crustacea, brachyura, pinnotheridae)

Abstract

The male copulatory system of the European pinnotherid species Pinnotheres pisum, Pinnotheres pectunculi, and Nepinnotheres pinnotheres was investigated by gross morphology, scanning electron microscopy, histological methods, and confocal laser scanning microscopy. The brachyuran copulatory system is consistently formed by paired penes and two pairs of abdominal appendages, the gonopods, functioning in sperm transfer. In pinnotherids, the long first gonopods transfer the sperm mass into the female ducts. The first gonopod has the ejaculatory canal inside that opens both basally and distally. The second gonopod is solid, short, and conical. During copulation, the penis and the second gonopod are inserted into the basal lumen of the first gonopod. While the penis injects the sperm mass, the second gonopod functions in the transport of spermatozoa inside the ejaculatory canal toward its distal opening. The second gonopod is adapted for the sealing of the tubular system in the first gonopod by its specific shape and the ability to swell. Longitudinal cuticle foldings of the second gonopod hook into structures inside the first gonopod. The second gonopod can interact with the penis during copulation by a flexible flap separating the lumina in which the second gonopod and the penis are inserted.

The morphology of the reproductive system in the crab Percnon gibbesi (Decapoda: Brachyura: Grapsoidea) reveals a new combination of characters in Thoracotremata

“…The male copulatory system of Percnon gibbesi conforms to that of other thoracotreme eubrachyurans, with the penis emerging from the gonopore in sternite 8 (Guinot et al, ) and a long first gonopod (G1) that transfers the sperm into the female ducts (e.g., Pinnotheridae: Becker et al, ; Majoidea: Kienbaum, Scholtz, & Becker, ). The second gonopod (G2) is short and has presumably an accessory role in sperm transfer.…”

“…The second gonopod (G2) is short and has presumably an accessory role in sperm transfer. The penis of Brachyura is not the intromittent organ but represents the outermost extension of the ejaculatory duct of the reproductive system of males (Minagawa, Chiu, Kudo, & Takashima, ; Garcia & Silva, ; Castilho, Ostrensky, Pie, & Boeger, ; Becker et al, ; Guinot et al, ). It has been described as being equipped with muscles in several brachyuran species (Minagawa et al, ; Castilho et al, ; Zara, Toyama, Caetano, & López‐Greco, ).…”

“…Yet, the internal and external relationships of these groups are still controversial (Tsang et al, ). Nevertheless, the reproductive systems of representatives of all four groups have been investigated (Varunidae: Lee & Yamazaki, ; Ocypodidae: López‐Greco, Fransozo, Negreiros‐Fransozo, & Dos Santos, ; Lautenschlager et al, ; Pinnotheridae: Becker, Brandis, & Storch, ; Becker et al, ; Gecarcinidae: de Souza, Silva, Araujo, & Camargo‐Mathias, ; de Souza, Ogawa, Silva, & Camargo‐Mathias, ; Cryptochiridae: Vehof, van der Meij, Türkay, & Becker, ). However, considering the diversity of thoracotremes, there is still a huge lack of data concerning the reproductive systems of this group.…”

A new genus and species of pinnotherid crab (Decapoda: Brachyura: Pinnotheridae: Pinnothereliinae) with a unique male abdominal appendage, and its symbiotic relationship with a sipunculan worm (Sipuncula) from Miami, Florida, U.S.A.

“…In order for the pleopods to function, the AP must be lifted to expose them, a seemingly awkward position, but the mechanics of the AP during copulation are entirely unknown. Laboratory observations of the copulatory system and behavior are needed to explain the AP's function (Becker et al 2012). phy and preparation of graphs.…”

Reproductive traits of the symbiotic pea crab Austinotheres angelicus (Crustacea, Pinnotheridae) living in Saccostrea palmula (Bivalvia, Ostreidae), Pacific coast of Costa Rica

“…Detailed information about many aspects of the association between pinnotherid crabs and their host remain to be studied (McDermott 2006, Peiró et al 2011). Several studies addressed different reproductive aspects of these symbiotic crabs, including the morphology of the reproductive system (Becker et al 2011, 2012, 2013), mating system (Dos Santos-Alves and Pezzuto 1998, Baeza 1999, Peiró et al 2013), intraspecific latitudinal effects on different reproductive attributes (Lardies and Castilla 2001), as well as fecundity (Báez and Martínez 1976, Hines 1992, Cabrera Peña et al 2001, Lardies and Castilla 2001). Our knowledge about energy allocation in embryo production of pinnotherid crabs is scarce; however, results obtained from several species of pea crabs clearly demonstrated that brood masses of these crabs are extraordinarily large in relation to female body size when compared to free-living decapods (Hines 1992, Lardies and Castilla 2001).…”