Revision of the Indo-Pacific gobiid fish genus Istigobius, with discussions of osteology and relationships

Typescript (photocopy).The Indo-Pacific gobiid fish genus Istigobius is revised based on the examination of 1366 specimens. The genus comprises 10 species distributed from the Red Sea to the Central Pacific: I. campbelli, I. decoratus, I. goldmanni, I. hoesei, I. hoshinonis, I. nigroocellatus, I. ornatus, I. perspicillatus, I. rigilius and I. spence. Species of Istigobius are sand-dwelling, many being associated with coral reefs. The characters of greatest importance in separating species proved to be those of color pattern. Nineteen meristic and morphometric characters were evaluated using multivariate analyses. Five meristic and seven morphometric characters were determined by Stepwise Discriminant Analysis to be of the greatest assistance in separating species. Investigations into the interrelationships of the genus Istigobius were also made using two genera which according to the literature were thought to be closely related (Acentrogobius and Favonigobius, mud-dwelling taxa) and five tropical sand-dwelling genera: Coryphopterus, Exyrias, Fusigobius, Gnatholepis, and Macrodontogobius. Istigobius has been found to form a monophyletic group with Exyrias and Macrodontogobius. The primitive sister group of this taxon is Acentrogobius; thus, the research hypothesis that tropical sand-dwelling gobies form a monophyletic group was refuted. Using Acentrogobius for outgroup comparison, hypothesized relationships within Istigobius were formulated