testis (...) while it is likely that Urbilateria lacked a complex somatic reproductive system, it is at present impossible to speculate on whether or not it possessed a true gonad, let alone any other somatic adaptations for reproduction (reference 1); Examination of different vertebrate species shows that the adult gonad is remarkably similar in its morphology across different phylogenetic classes. Surprisingly, however, the cellular and molecular programs employed to create similar organs are not evolutionarily conserved (reference 2).[uncertain][VHOG] A gonad of a male animal. A gonad produces and releases sperm. AAO:0000606 BILA:0000124 BSA:0000085 BTO:0001363 CALOHA:TS-1030 EFO:0000984 EHDAA2:0002007 EHDAA:8146 EMAPA:17972 EV:0100102 FBbt:00004928 FMA:7210 GAID:396 HAO:0001007 MA:0000411 MAT:0000132 MESH:A05.360.444.849 MIAA:0000132 Male reproductive organ.[TAO] OpenCyc:Mx4rvVjM25wpEbGdrcN5Y29ycA TAO:0000598 The testes are descended in metatherian and eutherian mammals, first transabdominally, then inguinoscrotally UBERON:0000473 UBERON:0002117 UMLS:C0039597 VHOG:0000252 WBbt:0006794 XAO:0000157 ZFA:0000598 galen:Testis gonad of male genitalia gonad of male reproductive system male gonad orchis testes testicle testicular testiculus uberon gonad reproductive organ