Novitatesx ^AMERICAN MUSEUM PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, N.Y. 10024 Number 2779, pp. 1-12, figs. 1-7, table 1 February 8, 1984 On the Relationships of Phallostethid Fishes (Atherinomorpha), With Notes on the Anatomy of Phallostethus dunckeri Regan, 1913 LYNNE R. PARENT!' ABSTRACT The Phallostethidae (including Neostethidae) is western Pacific Dentatherina Patten and Ivantsoff a family comprised of approximately 20 species is proposed as the sister group of the Phallosteth- of small, fresh, brackish, and occasionally salt- idae. water atherinomorph fishes of Indo-Australia. The anatomy of Phallostethus Regan, the type Phallostethids have variously been suggested as genus, is poorly known because of the scarcity and closest relatives of the atherinoid or cyprinodon- unsatisfactory condition of available material. A tiform fishes among the atherinomorphs, or of the report on the anatomy of Phallostethus dunckeri polynemids or gobioids among the percomorphs. Regan, the sole species in the genus, based on ex- Phallostethids uniquely share several derived amination of the syntypes and on unpublished characters of the jaws and the anal fin with a group notes and sketches is also included. of Indo-Australian and Pacific atherinoids. The INTRODUCTION The phallostethids (Atherinomorpha, pium (Regan, 1913, 1916), and among oth- Phallostethidae) are a little-known group of ers, a series of derived characters related to coastal fishes distributed throughout the Phil- reproduction as, for example, the anterior ippines, Borneo, Java, Malay Peninsula, and placement of the urogenital opening and re- Southeast Asian mainland.2 They are defined duction and/or modification of the pelvic fins as monophyletic by a complex subcephalic and fin girdles (see Roberts, 1971b). copulatory organ in males, termed the pria- The primary purpose of this report is to 1 Research Associate, Department of Ichthyology, American Museum of Natural History. 2 Report of a collection of phallostethids from northwestern Sumatra (Aurich, 1937) is considered to be unconfirmed. Copyright © American Museum of Natural History 1984 ISSN 0003-0082 / Price $1.25 AMERICAN MUSEUM NOVITATES NO. 2779 present the hypothesis of close relationship coetoids (flying fishes, halfbeaks, sauries, and among the phallostethids and several atheri- needlefishes) into the newly named series noid genera of Indo-Australia and the Pacific. Atherinomorpha, which he considered to be The definition and relationships of phallo- most closely related to the series Percomor- stethid species and genera are the subjects of pha. Rosen and Parenti (1981) formally de- an ongoing study (Parenti, in prep.). How- fined the atherinomorph fishes, giving as sev- ever, such a study could not be carried out eral of their derived characters specializations without a detailed, well-corroborated hy- of the egg, embryo, sperm formation, rostral pothesis of the relationship of phallostethids cartilage and association of the premaxillary to other fishes. ascending processes, and dorsal gill arches. When phallostethids were first discovered, Phallostethids remained in the Atherino- it was assumed that they were viviparous cy- morpha based on their possession of several prinodontiforms (then Microcyprini) be- of these derived characters. Rosen and Par- cause the priapium superficially resembles enti (1981) concluded that the atherinoid intromittent organs found among some fishes are not currently definable as mono- members of that group, for example, poecili- phyletic and simply listed the families of ath- ids (Regan, 1913, 1916). Smith (1927) re- erinoids in their Division I of the Atherino- ported that phallostethids which he observed morpha, abandoning the use of the term in Thailand were oviparous. The priapium is atherinoid in formal classification to empha- apparently used by males for passing sperm size uncertainty in our knowledge of rela- bundles to females who subsequently lay fer- tionships of these fishes (table 1). tilized eggs, although details of priapial func- The phallostethids have undergone eleva- tion are unknown. tions and reductions in taxonomic rank since Both Herre (1925) and Myers (1928) point- their discovery; however, no formal state- ed out that some phallostethids have a spi- ment concerning their relationship to another nous first dorsal fin which is lacking in the group of fishes has been made previously. cyprinodontiforms. On this basis, and be- Myers (1935) created a new suborder within cause of the overall resemblance of phallo- the Percesoces, what he termed Phallosteth- stethids to atherinid fishes (the silversides or oidea, which served to emphasize further the hardyheads), Myers transferred the phallo- unique characters of these fishes. Rosen (1964) stethids to the order Percesoces, which then placed the phallostethids in the superfamily contained the silversides, mullets, barracu- Phallostethoidea, suborder Atherinoidei, but das, and threadfins. Bailey (1936) proposed suggested that they may be more closely re- that phallostethids were close relatives of the lated to the cyprinodontiforms. Roberts threadfins (the polynemids) based on a su- (1971b) speculated that phallostethids are perficially similar association of the pectoral closely related to the atherinid subfamily and pelvic fins. Taeniomembradinae of Schultz (1948, 1950). Hubbs (1944) concurred with Myers that However, the Taeniomembradinae was not the phallostethids were more closely related defined by Schultz as monophyletic. He stat- to the atherinids than to the cyprinodonti- ed only that these atherinids possess the forms; however, whereas Myers considered primitive state of the swimbladder character the cyprinodontiforms and the atherinids to used to define a relatively more derived be closely related, Hubbs considered the subfamily. Even the idea that phallostethids percesocans (including the phallostethids and are atherinomorph fishes has been ques- atherinids) to have a relatively more derived tioned recently by V. G. Springer (personal fin structure than that of the cyprinodonti- commun.) who suggests that they may be forms. Thus, Hubbs supported an alignment closely related to the gobioid fishes. of the percesocans closer to some of the per- This report was prompted by: (1) the recent ciform fishes. discovery and diagnosis of a new genus and Rosen (1964) placed the phallostethids, species of atherinid, Dentatherina merceri by atherinids, cyprinodontiforms, along with the Patten and Ivantsoff (1983), which I propose adrianichthyoids (the ricefishes), and the exo- as the closest living relative of the phallo- 1984 PARENTI: PHALLOSTETHID FISHES stethid fishes; (2) the opportunity to examine TABLE 1 Regan's syntypes of Phallostethus dunckeri Classification of Atherinomorph Fishes at the British Museum (Natural History); and, (From Rosen and Parenti, 1981) (3) most important, by the gift of notes and sketches prepared by Dr. Ethelwynn Trewa- Series Atherinomorpha vas in the 1930s as part of her planned re- Division I vision of phallostethid fishes. Both because Family Atherinidae Family Bedotiidae of the scarcity of material and present poor Family Isonidae condition, which precludes a formal rede- Family Melanotaeniidae scription, Dr. Trewavas's notes and sketches Family Phallostethidae of P. dunckeri contain some of the only data Family Telmatherinidae available on the anatomy of this unique Division II species. Order Cyprinodontiformes Order Beloniformes ACKNOWLEDGMENTS Dr. Donn E. Rosen, American Museum of Drs. Ivantsoff, John Patten, and Rosen read Natural History, New York, has frequently and commented on the manuscript. discussed aspects of atherinomorph anatomy and systematics with me. Dr. Tyson R. Rob- Phallostethus dunckeri Regan erts, California Academy of Sciences, San Francisco has, on numerous occasions, freely Phallostethid anatomy has been the focus given information on the anatomy and dis- of numerous studies published since Regan's tribution of phallostethids. Drs. Walter (1913) description of Phallostethus dunckeri Ivantsoff, Macquarie University, Australia, (e.g., Regan, 1916; Myers, 1928; Bailey, 1936; and Brian White, Los Angeles County Mu- Aurich, 1937; TeWinkle, 1939; Herre, 1942; seum of Natural History, Los Angeles, kindly Woltereck, 1942a, 1942b; Hubbs, 1944). shared information on atherinoids. The re- Roberts (1971a, 1971b) presented the most port on the anatomy of Phallostethus dunck- recent reviews of some problems in phallo- eri Regan would not have been possible with- stethid anatomy and systematics. He stated out the gift of notes and sketches made by that basic comparative data of Phallostethus Dr. Ethelwynn Trewavas, Curator Emerita, are unknown because Regan (1913) did not British Museum (Natural History) as well as report states of characters which we now con- her kind permission to use them here. sider to be useful in defining phallostethid I thank Drs. P. Humphry Greenwood, Brit- relationships, and because P. dunckeri is ish Museum (Natural History), London known today only from syntypes (Roberts, (BMNH), Gareth Nelson, American Mu- 1971b). For example, Roberts stated that the seum of Natural History, New York (AMNH), number of branchiostegal rays, and whether and Richard P. Vari and Ms. Susan L. Jewett, or not P. dunckeri has a first dorsal fin, were National Museum of Natural History, Smith- unknown. sonian Institution, Washington, DC. Regan (1913) based his description of (USNM), for lending or allowing me to