Phylogenetic tree of bilaterian otx genes with aristaless (arx) as outgroup. Protein sequences were obtained from the published literature or BLAST searches of the NCBI GenBank. The tree is built with the amino-acid sequences from Maximum likelihood analysis. The two orthologs of otx in chelicerates (named otxa and otxb in Cupiennius) does not correspond to otx1 and otx2 of vertebrates showing that the duplication of the genes in chelicerates had happened independently from duplication of otx in vertebrates. Arthropods’ otx genes do not form a monophylum and position of chelicerates’ two orthologs within the arthropods is unresolved. Table S5 List of the species names, their phylum, and their abbreviation, the gene names and the GeneBank accession numbers used in phylogenetic analysis of otx genes. Abbreviation Aec_ocl Accession info EGI70731 Species name Acromyrmex echinatior Phylum Arthropoda Aga_otx Ame_ocl Api_otd Bmo_arx XP_310918 XP_006571327 XP_001948393 XP_004929200 Anopheles gambiae Apis mellifera Acyrthosiphon pisum Bombyx mori Arthropoda Arthropoda Arthropoda Arthropoda Bmo_otd Cgi otx5 Cgr_otx2 Cpi otx2 Csa otxa Csa otxb Csa_arx Dme_ocl Dme_otd Dre_otd1 Efl_otd Eka arx Eka_otd XP_310918 EKC28141 ERE92634 XP_005295567 LN624820 LN624821 To be submitted NP_001014727 CAA41732 NP_571325 AAU85255 CDK60408 LN650633 Bombyx mori Crassostrea gigas Cricetulus griseus Chrysemys picta Cupiennius salei Cupiennius salei Cupiennius salei Drosophila melanogaster Drosophila melanogaster Danio rerio Euscorpius flavicaudis Euperipatoides kanangrensis Euperipatoides kanangrensis Arthropoda Mollusca Chordata Chordata Arthropoda Arthropoda Arthropoda Arthropoda Arthropoda Chordata Arthropoda Onychophora Onychophora Gma_otd Hsa_otx1 Isc_hox? Laf_otx2 Lch otx2 Mdo_arx Moc_otx1 Obi_otd Pca_otd Pre_otx1 Pte otd1 Pte otd2 Rno_otx1 Sca_otx2 Sma_otx Smi_arx Smi_otx1 Smi_otx2 Spa_otx2 Sra_ocl Tca_otd1 Tca_arx Tsa_otx CAK50843 NP_055377 XP_002403318 XP_003408715 XP_005986517 XP_005181478 XP_003742052 AAZ99218 AFY12008 XP_008416164 AB096074.1 KP725073 NP_037241 AAP04272 ABY74501 KFM57110 KFM58880 KFM60429 XP_008281544 CEF62108 NP_001034513 XP_008193910 AAU85252 Glomeris marginata Homo sapiens Ixodes scapularis Loxodonta africana Latimeria chalumnae Musca domestica Metaseiulus occidentalis Octopus bimaculoides Priapulus caudatus Poecilia reticulata Parasteatoda tepidariorum Parasteatoda tepidariorum Rattus norvegicus Scyliorhinus canicula Strigamia maritima Stegodyphus mimosarum Stegodyphus mimosarum Stegodyphus mimosarum Stegastes partitus Strongyloides ratti Tribolium castaneum Tribolium castaneum Tegenaria saeva Arthropoda Chordata Arthropoda Chordata Chordata Arthropoda Arthropoda Mollusca Priapulida Chordata Arthropoda Arthropoda Chordata Chordata Arthropoda Arthropoda Arthropoda Arthropoda Chordata Nematoda Arthropoda Arthropoda Arthropoda