Phylogenetic relationships between the species included in this study. The presence and number of Dscam orthologs and co-orthologs (I. scapularis, I.s.), Dscam-hv orthologs, and putative alternatively spliced exons within Immunoglobulins 2, 3 and 7, are indicated for each species. Grey horizontal boxes highlight the species for which our study adds some information: more specifically, black numbers show putative genes found or annotated in this study and black dashes show that we did not find Dscam orthologs/paralogs for that species. Grey numbers show the Dscam genes and Dscam-hv that were annotated or described prior to this study, although the number of Ig exon variants shown are those predicted by our HMMs. The genome of L. vannamei is not sequenced so the grey question marks indicate that we could not search for Dscam-like genes in this species. * indicates genes which were used to build HMMs to search for Dscam orthologs, and ‡ indicates genes which were used to build the Dscam-hv HMMs. § For reasoning why this is 47 and not 48, please see Additional file 2. L. vannamei alternatively spliced exon numbers are conservative estimates . Vertical bars indicate the main taxa of interest in this study, where A stands for Arachnida. Species relationships from [29–35].