Abstract
This paper discusses the systematics and phylogeny of the genus Tambja Burn, 1962 throughout tropical and temperate areas in the Atlantic, eastern Pacific and Indo‐Pacific. The phylogenetic relationships within Tambja are unknown and a comprehensive taxonomic revision is necessary in order to construct a phylogeny of the genus. To date, Tambja comprises 28 nominal species, 22 of which have been examined morphologically based on newly collected and type material. The reproductive systems of four species ( T. limaciformis (Eliot, 1908), T. sagamiana (Baba, 1955), T. amakusana , Baba, 1987 and T. olivaria , Yonow, 1993) were studied for the first time and two species previously considered as valid, Tambja morosa (Bergh, 1877) and Tambja kushimotoensis Baba, 1987, are here synonymized. Of the remaining six nominal species, no additional material has been found since their original description. The holotypes of three ( T. diaphana (Bergh, 1877), T. gratiosa (Bergh, 1890) and T. marbellensis Schick & Cervera, 1998) have been re‐examined and the original descriptions improved. Tambja diaphana is regarded as nomen dubium . Tambja amitina (Eliot, 1905), T. divae (Marcus, 1958) and T. anayana Ortea, 1989 remain as valid species until further comparison with new specimens can be made. New structures are also described for several taxa. Morphological and anatomical data from 22 nominal Tambja species have been used to construct a phylogeny. The phylogenetic analysis rejects the monophyly of Tambja and shows its preliminary relationships within the subfamily Nembrothinae.