High sexual display trait diversity without measured genetic divergence in a montane hybrid zone involving young species (Habronattus americanus subgroup, Araneae: Salticidae).

This article focuses on the genetic and morphological dynamics of a hybrid zone between two recently diverged jumping spider species, *Habronattus americanus* and *Habronattus kubai*, on Mount Shasta, California. Using morphological analyses and double-digest restriction-site-associated DNA sequencing (ddRADseq), the study found extensive hybridization with a diverse array of hybrid male phenotypes forming a phenotypic bridge between parental species, despite minimal genomic differentiation among morphs. The contact zone contains more hybrids than parental individuals, with a predominance of red-palped males, a trait possibly favored by female preference and linked to sexual selection. Additionally, a novel white-palped phenotype, absent in either parental species, was identified, suggesting transgressive hybrid traits may arise through introgression. These findings illustrate the complex interplay of gene flow, sexual selection, and species boundary maintenance during early speciation stages in this spider subgroup.