Contrasting morphological and genetic patterns suggest cryptic speciation and phenotype-environment covariation within three benthic marine hydrozoans

Author(s)

Cunha, Amanda Ferreira ; Carmelet-Rescan, David ; Marques, Antonio Carlos ; Morgan-Richards, Mary

• Document type: Journal article
• Source: Marine Biology; v. 169, n. 8, p. 17-pg., 2022-08-01.

Abstract

Connectivity among populations of widespread marine species is expected to be correlated with their dispersal potential but the evolution of reproductive barriers may account for variations in spatial genetic patterns. Marine benthic hydroid species are traditionally considered widespread, with long-distance rafting presumably increasing their dispersal potential. In this study, we investigated the relationship between genetic, morphological and environmental variability within three benthic marine hydroid species to evaluate current patterns of genetic variation and assess the existence of cryptic speciation. Although a long-lived planktonic stage is absent in all the lineages sampled and they have an overlapping geographical ranges, we observed contrasting patterns of genetic and phenotypic divergence: Orthopyxis sargassicola showed little genetic variation, while O. caliculata and O. crenata each contained high genetic differentiation, primarily suggesting limited dispersal potential. Significant covariation was observed between phenotypic and environmental data in all lineages, but different environmental variables were responsible for explaining morphological variation in each case. Genetic and morphological patterns within O. caliculata and O. crenata are suggestive of cryptic speciation, while phenotypic variation in O. sargassicola may be plastic. Thus, morphological and genetic patterns may potentially vary among related marine lineages with shared life history traits and habitat. (AU)

• FAPESP's process: 18/24781-5 - Understanding the role of genes and the environment in determining phenotypic variation in the genus Orthopyxis (Cnidaria, Hydrozoa) from the southwestern Atlantic Ocean
• Grantee: Amanda Ferreira e Cunha
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 11/50242-5 - Dimensions of marine life: patterns and process of diversifications in planktonic and benthic cnidarians
• Grantee: Antonio Carlos Marques
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 17/00641-7 - Morphological variability within the evolutionary context of colonial hydrozoans (Cnidaria, Proboscoida)
• Grantee: Amanda Ferreira e Cunha
• Support Opportunities: Scholarships in Brazil - Post-Doctoral