Secondary sexual characters and spermatophores of Solenocera agassizii (Decapoda: Solenoceridae), including a comparison with other solenocerid shrimp

Abstract

Solenocera agassizii is commercially exploited along the Costa Rican Pacific coast and represents around 30% of the country's total shrimp catch. Despite its economic importance, information on its biology is scarce. Here we describe its secondary sexual characters and spermatophores. The open thelycum is located between Sternites XIII and XIV. A pair of parallel setose projections (Sternite XIV) is distally curved in larger females (< 30 mm carapace length); a disk-shaped projection (Sternite XIII) emerges from Pereopod IV and projects towards Sternite XIV, and a triangular emargination is present (Sternite XIII). The semi-open petasma with cincinnulli connecting the pleopods in mature males has sclerotized dorsolateral (DL), ventrolateral (VL) and ventromedian (VM) lobules. The VM tooth-like projections fit the VL tooth-like projections. The DL and VL lobules end in a leaf-like, less sclerotized projection and are separated by a gap. The VL lobule has a patch of spinules and a highly sclerotized costa. An elongated appendix masculina (AM) with concave margin forms a distal subtriangular lobe and has a DL margin with an aggregation of setae. The AM fits inside the appendix interna (AI) and is shorter and narrower than the AM. The spermatophore has superior (wing) and inferior (germinate body) sections. The GB ends in a triangular hook-like structure. The thelycum resembles that of S. geijskesi, whereas the petasma, AM and AI are similar to those of Atlantic solenocerids. The complex spermatophore resembles that of other penaeoid shrimp. According to evolutionary trends, S. agassizii can be considered as a less derived species within the Dendrobranchiata.

Reproductive biology of the commercially exploited kolibri shrimp, Solenocera agassizii (Decapoda: Solenoceridae), from the Pacific coast of Costa Rica, with considerations for its management

“…Accordingly, the SMM obtained in the present study should coincide with the size at which the thelycum of S. agassizii is fully developed. This assumption is corroborated by the fact that SMM obtained in the present study coincides with the minimum size at which spermatophores were found attached to the thelycum (from 28.5 mm CL) (Villalobos-Rojas & Wehrtmann, 2014).…”

“…This species represented up to 30 % of the total shrimp landings of Costa Rica between 2001 and, with the highest yearly landings in 1986 (2.6 x 10 6 kg) (Wehrtmann & Nielsen-Muñoz, 2009) followed by a continued reduction since 2005 (0.57 x 10 6 kg) to roughly 0.0061 x 10 6 kg in 2014 (Instituto Costarricense de Pesca y Acuicultura [INCOP-ESCA]). Despite this alarming situation and the economic importance of this species, the knowledge about the biology of S. agassizii is rather limited (Villalobos-Rojas & Wehrtmann, 2011;Rodríguez et al, 2012;Villalobos-Rojas & Wehrtmann, 2014). Such a scenario hinders any effort to develop an appropriate management plan for the sustainable exploitation of this resource.…”