Description of ten additional ossicles in the foregut of the freshwater crabs Sylviocarcinus pictus and Valdivia serrata (Decapoda: Trichodactylidae)

Renata C Lima-Gomes,Jô De Farias Lima,Célio Magalhães

doi:10.3897/zoologia.34.e13731

Abstract

The morphology of stomach ossicles of decapod crustaceans provides valuable information on their phylogeny and biology. We herein described ten new ossicles in the foreguts of two trichodactylid crabs, Sylviocarcinus pictus (H. Milne-Edwards, 1853) and Valdivia serrata White, 1847, in addition to previously described 38 ossicles, which are also recognized and listed. Five specimens each of S. pictus and V. serrata were selected for morphological analysis of gastric ossicles. The stomachs were obtained after removing the carapace, and they were fixed in 10% formalin for 24 hours. After this procedure, the stomachs were immersed in a solution of 10% Potassium Hydroxide (KOH) and heated to 100 °C during 60 minutes for tissue maceration. At this point, the clean skeletons were colored by adding 1% Alizarin Red to the KOH solution in order to facilitate visualization of the internal structures such as the setae and ossicles. The ten new ossicles are: dorsomedial cardiac plate; dorsolateral cardiac plate; suprapectineal lateral ossicle; inferior cardiac valve; lateral mesopyloric ossicle; ampullary roof-medium portion ossicle; process of the ampullary roof-upper portion; lateral-inferior post-ampullary plate; pleuro-pyloric valve?s ossicle; and lateral pleuro-pyloric plate. Some ossicles are thin plates that together with the main ossicles assist in the structure and support of the stomach, which are similar in the two species studied herein. The current knowledge on gastric ossicles will be useful in establishing taxonomic characters, which can evaluate phylogenetic relationships among brachyuran crabs.

Highlights

The stomach of decapod crustaceans is composed of a muscular and nervous complex called gastric mill (Meiss and Norman 1977), where a system of striated muscles performs movements of skeletal elements that work together to break and grind large particles of food in the cardiac chamber
Many studies have been undertaken to understand how this complex operates in different decapods since the gastric skeleton can provide valuable information on their phylogeny and biology, especially their feeding habits (Felgenhauer and Abele 1983, 1985, Brösing et al 2002, Abrunhosa et al 2003, Brösing et al 2006, Brösing 2010, Alves et al 2010)
The morphology of stomach ossicles can be an important source for taxonomic characters and is potentially useful for studying phylogenetic relationships in different groups of decapods (Sakai 2005, Sakai et al 2006, Naderloo et al 2010, Brösing and Türkay 2011)

Summary

Introduction

The stomach of decapod crustaceans is composed of a muscular and nervous complex called gastric mill (Meiss and Norman 1977), where a system of striated muscles performs movements of skeletal elements that work together to break and grind large particles of food in the cardiac chamber. In addition to the support of the gastric skeleton, the ossicles assist in crushing and filtration activities during the feeding process. Many studies have been undertaken to understand how this complex operates in different decapods since the gastric skeleton can provide valuable information on their phylogeny and biology, especially their feeding habits (Felgenhauer and Abele 1983, 1985, Brösing et al 2002, Abrunhosa et al 2003, Brösing et al 2006, Brösing 2010, Alves et al 2010). The morphology of stomach ossicles can be an important source for taxonomic characters and is potentially useful for studying phylogenetic relationships in different groups of decapods (Sakai 2005, Sakai et al 2006, Naderloo et al 2010, Brösing and Türkay 2011).

Methods

Results

Conclusion