Butis butis (Hamilton, 1822) (Figs 1-3B, 5; Tables III-IV) The species of the genus Butis are often fished and numerous papers refer to these species. As it exists several cryptic species (this paper) and at least 6 different species in India (this paper), it is necessary to clarify the status of Butis butis (Hamilton, 1822) from India (type locality), which is one of the most cited species. This name has been used for a species of Butis since 1822 and it seems reasonable to decide to settle it. As the type of this species is not objectively identifiable, the name B. butis can only be linked to a known taxon by a neotype designation (ICZN, 1999: art. 75.3.1). It is currently considered that there are no types known (Fricke et al., 2022) and Britz (2019), expert on Hamilton’s work, wrote that there is no evidence at all that Hamilton preserved any fish when making his descriptions. Günther (1861) listed one specimen presented by G.R. Waterhouse as a probable type (i.e., possible type BMNH 1858.8.15.142). Hora (1929) indicated no Hamilton type material retained, arguing that none of the material presented by Waterhouse could be types. After examination of the specimen BMNH 1858.8.15.142 (this study; Fig. 7A; Table I), we consider that it is a B. humeralis and there is no evidence that it could be the type B. butis according to the description of Hamilton. Finally, J. Maclaine (BMNH, Senior Curator, fish section; pers. comm.) confirmed that there is no type in BMNH considered to be the B. butis of Hamilton (ICZN, 1999: art. 75.3.4). For these reasons, to avoid confusion we designate here the specimen MNHN 2022-0233 (male, 55.2 mm SL) from India as neotype of Butis butis (Hamilton, 1822) (Fig. 5A), which comes from the original type locality (ICZN, 1999: art. 75.3.6). The MNHN is a recognized scientific institution that maintains a research collection, with proper facilities for preserving name-bearing types, and that makes them accessible for study (ICZN, 1999: art. 75.3.7). Data and diagnostic characters differentiating from other taxa are given below (in the description and comparison paragraphs) to ensure recognition of the specimen designated (ICZN, 1999: art. 75.3.2 and 75.3.3). The description of Hamilton (1822) did not give sufficient or diagnostic data to state on the species (several species have the two red spots at the base of the pectoral fins as cited by Hamilton (1822) and as shown in the unpublished drawing (Fig. 5B) of Hamilton and reproduced by Britz (2019), or have 18 rays in pectoral fins). Thus a neotype designation is needed to clarify the identity, and the neotype here is consistent with the poor original description (see below) (ICZN, 1999: art. 75.3.5). Material examined MNHN 2022-0233, neotype, male (55.2 mm SL), India (Fig. 5A).

Published as part of Keith, Philippe & Mennesson, Marion I., 2023, Review of Butis (Teleostei: Butidae) from Indo-Pacific islands with description of three new species, pp. 431-466 in Cybium 47 (4) on page 445, DOI: 10.26028/cybium/2023-034, http://zenodo.org/record/12713757