A Genomic Contribution to the Classification of the Blennioid Fishes of the Family Clinidae
There are presently four recognized species of clinid (kelpfish family: Clinidae) on the west coast of North America: Gibbonsia elegans, G. metzi, G. montereyensis, and Heterostichus rostratus. In addition, Clark L. Hubbs proposed an endemic subspecies in the genus Gibbonsia on Guadalupe Island. Later investigations using allozymes indicated low levels of genetic diversity between populations and treated subspecies names as synonyms, leading to the present-day status of three species in the genus. Here, we use high-throughput sequencing and a combination of nuclear and mitochondrial markers to revisit the systematics and population structure of the genus Gibbonsia. We find that Guadalupe Island specimens that are morphologically identified as G. elegans form a distinct genetic lineage for both nuclear and mitochondrial markers, supporting Hubbs’s hypothesis of a Guadalupe Island endemic, Gibbonsia erroli. Further, we find that while dispersal potential is high for all species in the genus, genome-wide markers and outlier analyses show population structure at short geographic distances, suggesting fine scale environmental variation leading to local adaptation.
Map of sample locations. Main map shows sample locations in Southern California (Catalina Island) and Mexico (Guadalupe Island). Inset shows locations in Central California, from north to south: Ocean Cove, Half Moon Bay, Pigeon Point, Davenport, Moss Landing, Pacific Grove.
Maximum-likelihood phylogenetic tree with bootstrap values inferred using RADseq SNPs (left panel). Tip labels are an abbreviated location and sample number. Red triangle represents a collapsed tip which includes >1 sample with total number of samples shown in parentheses. Guadalupe Island samples are labeled as G. erroli. Images of species are recreated illustrations from Hubbs (1952). Neighbor-joining phylogenetic tree using mitochondrial 16S rRNA marker with Heterostichus rostratus as an outgroup (right panel). Samples from Guadalupe Island, Mexico are labeled G. erroli. Number of specimens included in each tip are shown in parentheses. See Data Accessibility for tree files.
(A) Principal component analysis of all species separating G. montereyensis (GMO) and G. metzi (GME) on PC1 and G. elegans (GEL) and G. erroli (GER) on PC2. PCA for (B) G. metzi and for (C) G. montereyensis using all loci. (D) PCA for G. montereyensis using outlier loci.
Graph showing the distribution of the number of dorsal spines for subspecies of G. elegans, redrawn from Hubbs (1952). First row shows data for the Guadalupe Island endemic G. erroli.
Contributor Notes
Associate Editor: M. T. Craig.