Homalopteroides Fowler 1905

Randall, Zachary S. & Page, Lawrence M., 2012, Resurrection of the genus Homalopteroides (Teleostei: Balitoridae) with a redescription of H. modestus (Vinciguerra 1890), Zootaxa 3586, pp. 329-346 : 335-337

Homalopteroides Fowler 1905

( Figs. 1B, 2B, 4, 5, & 6)

Homalopteroides Fowler, 1905: 476 . (Type species: Homaloptera wassinkii Bleeker 1853 , by original designation [the type species was misidentified, see below.]). Gender masculine.

Chopraia Prashad & Mukerji, 1929: 188 (Type species: Chopraia rupicola Prashad & Mukerji, 1929 , by original designation). Gender feminine.

Fowler (1905) designated Homaloptera wassinkii Bleeker 1853 as the type species of Homalopteroides . The description given by Fowler for H. wassinkii was inaccurate and has caused confusion for authors, including Weber and de Beaufort (1916). The specimens (ANSP 68718) examined by Fowler are identifiable as Homaloptera weberi Hora 1932 when compared to the seven syntypes of H. weberi (BMNH 1895.7.2.81). They all have an orbital length greater than or equal to the interorbital width, and a pelvic fin that extends past the anus. Fowler inaccurately gave a total pectoral-fin ray count of 14 (v, 9) and an inaccurate count of 38 lateral-line scales from the gill opening to the base of the caudal fin. Correct counts are 16 (v, 10, i) rays and 45–47 scales.

Art. 70.3 of the International Code of Zoological Nomenclature ( ICZN 1999) addresses misidentified type species. According to the provisions of the article, the species that will best serve stability and universality can either be the nominal species cited and misidentified (Art. 70.3.1, H. wassinkii Bleeker 1853 ) or the taxonomic species examined (Art. 70.3.2, H. weberi Hora 1932 ). The genus Homalopteroides is valid, and both of these species are members. We choose to retain the type species as H. wassinkii Bleeker 1853 (Art. 70.3.1).

Diagnosis. Homalopteroides is distinguished from Homaloptera by the following combination of characters: dorsal-fin origin over pelvic fin, ≤ 60 lateral-line scales, ≤ 30 predorsal scales, and a mouth morphology consisting of two thin and widely separated rostral barbels on each side of the mouth, thin crescent-shaped lips, the absence of any structure such as a mental pad or lobes ( Fig. 2 D) between the lateral portions of the lower lip, and a chin that extends anterior to the lateral portions of the lower lip. Based on these characters, the following species are removed from Homaloptera and placed in Homalopteroides : Homaloptera wassinkii Bleeker 1853 , H. modesta ( Vinciguerra 1890) , H. rupicola ( Prashad & Mukerji 1929) , H. smithi Hora 1932 , H. stephensoni Hora 1932 , H. weberi Hora 1932 , H. tweediei Herre 1940 , H. indochinensis Silas 1953 , H. nebulosa Alfred 1969 , H. yuwonoi Kottelat 1998 , and possibly (see Discussion) H. manipurensis Arunkumar 1999 .

Even with the transfer of species to Homalopteroides , Homaloptera remains a highly variable genus with species assigned to three subgenera: Homaloptera (Homaloptera) , H. (Balitoropsis), and H. (Homalopterula). Due to this large morphological variation, Homalopteriodes can be distinguished from Homaloptera only by a combination of characters. All characters used to distinguish Homalopteroides from the subgenera of Homaloptera are described below.

Homalopteroides is distinguished from Homaloptera (Homaloptera) ( Figs. 1A & 2A) by having the origin of the dorsal fin posterior, rather than anterior, to the origin of the pelvic fin, ≤ 60 total lateral-line pored scales vs. 60–67 for H. ocellata van der Hoeven 1833 , 66–73 for H. bilineata Blyth 1860 , 65 for H. orthogoniata Vaillant 1902 , 60–63 for H. ogilviei Alfred 1967 , 63 for H. confuzona Kottelat 2000 , and 75–77 ( Tan & Ng 2005) for H. parclitella Tan and Ng 2005 , thin barbels with the medial- and lateral-rostral barbels widely separated from one another at the base versus barbels thick and in close proximity to one another, crescent rather than triangularshaped lips, and the absence versus presence of a mental pad.

Homalopteroides is distinguished from Homaloptera (Balitoropsis) ( Figs. 1C & 2C) by having the origin of the dorsal fin posterior, rather than at or anterior to, the origin of the pelvic fin. The same mouth characters listed above for distinguishing Homalopteroides from H. ( Homaloptera ) distinguish Homalopteroides from H. (Balitoropsis) except lip shape, which can be crescent-shaped as in H. (Balitoropsis) zollingeri Bleeker 1853 ( Fig 2C).

Homalopteorides is distinguished from Homaloptera (Homalopterula) ( Figs. 1D & 2D) by having ≤ 60 total lateral-line pored scales vs. 64–66 for H. (Homalopterula) gymnogaster Bleeker 1853 , 63–70 ( Weber & de Beaufort 1916) for H. (Homalopterula) heterolepis Weber and de Beaufort 1916 , 70–74 for H. (Homalopterula) ripleyi ( Fowler 1940) , and 75 for H. (Homalopterula) vanderbilti Fowler 1940 , ≤ 30 predorsal scales vs. 49–50 for H. gymnogaster , more than 50 ( Weber & de Beaufort 1916) for H. heterolepis , 43–47 for H. ripleyi , and 56 for H. vanderbilti , thin vs. thick lips, the absence versus presence of mental lobes between the lateral portions of the lower lip, and a chin that extends anterior to, rather than up to, the lateral portions of the lower lip.