Morphologic description of the first larval stage of the shrimps from genus Synalpheus Spence Bate, 1888 (Caridea, Alpheidae) from the São Paulo state coast, including a review of the larval morphology of Synalpheus

Author(s)

Rafael De Carvalho Santos

• Document type: Doctoral Thesis
• Press: Botucatu. 2022-07-27.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Botucatu
• Defense date: 2022-05-25
• Advisor: Rogerio Caetano Costa

Abstract

Synalpheus is the second most specious and ecologically diverse genus of the Alpheidae family. Synalpheus species present different types of larval development and, nevertheless, information on their larval morphology is available only for about 9% of the total of species described for the genus. This study aims to describe the first larval stage of the species Synalpheus antillensis, S. apioceros, S. fritzmuelleri, S. cf. townsendi, and Synalpheus sp., sampled in the state of São Paulo. Additionally, a review of the larval first larva morphology of the genus was also carried out. The specimens were sampled along the coast of the state of São Paulo and the species identification was confirmed using genetic distance analysis. The results of the larval description showed unique morphological characteristics for each of the five species, allowing their differentiation and identification in the environment, contributing to the construction of an identification key for the species occurring on the Brazilian coast. In addition, morphological characteristics shared between the species were observed, with an antennule with a 3- segmented peduncle being a possible distinctive character for zoeas I of Synalpheus. For S. fritzmuelleri, morphological differences were found when the description in this study was compared with the one carried out previously, indicating the need to review the old descriptions within the genus. The descriptions of Synalpheus presented here were compared with each other and with seven other species already described in the literature. The 12 species shared among themselves only the absence of spines on the carapace, sessile eyes, and the rounded shape of the telson. The greatest morphological similarities were found among larvae that had the same type of development. For S. antillensis, S. apioceros, S. fritzmuelleri, S. minus, S. neomeris, S. pectiniger, S. cf. townsendi, S. tumidomanus, and Synalpheus sp., development was considered extended, showing a morphology commonly found in Zoea I of carideans after hatching. After review, for S. biunguiculatus, S. neptunus and S. brooksi the abbreviated development was considered, however with differences in the morphology of the first larval stage between these three species, which demonstrates the formation of morphological subgroups for this type of larval development in Synalpheus. Thus, the results presented contribute information to the taxonomy and life history of the genus, expanding the available literature on the morphology and development of the larvae of the genus, and helping in the identification process. (AU)

• FAPESP's process: 18/00739-0 - Description and identification of the morphology of the first larval stage of the shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda, Caridea, Alpheidae) of the coast of the State of São Paulo
• Grantee: Rafael de Carvalho Santos
• Support Opportunities: Scholarships in Brazil - Doctorate