Subject: Odontaspidid systematics and nomenclature
Date: Tue, 03 Jun 1997 15:17:55 -0200
From: Leonard
To: Elasmo-L@umassd.edu

Dear Elasmo-L

I note with interest the continuing discussion on the systematics and nomenclature of sand tiger sharks (ODONTASPIDIDAE). Note that the comment that I supposedly thought (Compagno, 1984, FAO shark catalog) that Odontaspis noronhai was only an extreme variant of O. ferox was taken out of context. To quote from the FAO catalog account of O. noronhai (p. 222): "Compagno (1981a) recognized this species [O. noronhai] but suggested that it possibly was only an extreme variant of O. ferox. However, additional evidence convinced the writer that it is a valid species, readily separable from O. ferox." Additional information further verifies the validity of O. noronhai.

The issue of the nomenclature and systematics of the sand tiger shark, Carcharias taurus RAFINESQUE, 1810, is complex and has been covered in some detail by other writers to Elasmo-L. When a group of British paleontologists and ichthyologists (White, Tucker & Marshall, 1961) proposed that Carcharias RAFINESQUE, 1810 be replaced by Odontaspis AGASSIZ, 1838, they assumed that all of the numerous fossil species placed in Odontaspis were congeneric with all of the few living species placed in Carcharias by Bigelow & Schroeder (1948); hence as Odontaspis has more usage with the far more numerous fossil odontaspidid species, it should be substituted for Carcharias and the latter suppressed. The International Commission on Zoological Nomenclature (ICZN) ruled in favor of White *et al.* in 1965 on this matter, but this ruling quickly became irrelevant in the wake of what might be termed the 'Glickmanian Revolution' in lamnoid paleosystematics (starting with L. S. Glickman's 1964 book Paleogene sharks and their stratigraphic importance), which divided many of the Agassizian 'ragbag' fossil taxa such as Oxyrhina, Lamna, and Odontaspis (all based on living species) into separate genera. Odontaspis was restricted to Odontaspis ferox and its close fossil relatives, while Carcharias taurus and its living and numerous fossil relatives were placed in several genera including Synodontaspis WHITE, 1931 and Paradontaspis WHITE, 1931 (both based on living species).

The Glickmanian Revolution resulted in major oversplitting of the lamnoid genus and family-group taxa, but subsequent paleontological work as well as morphological studies of living species suggested that the generic separation of the ferox and taurus groups was real and of long-standing in the fossil record, and that the pre-Glickman ragbag genus Odontaspis had undergone severe and necessary restriction. I resurrected Eugomphodus GILL, 1862 for the taurus group (Compagno, 1977, 1984) because it was the oldest valid generic name available at the time in the wake of the ICZN's 1965 decision rejecting Carcharias RAFINESQUE, 1810 and Triglochis MUELLER & HENLE, 1837. Some paleontologists, including Cappetta (1987) in his review of Mesozoic and Cenozoic fossil elasmobranchs, preferred using Synodontaspis to Eugomphodus for living members of the taurus group and their immediate relatives. Various paleontologists and neontologists were unsatisfied with the decision rejecting Carcharias, however, but it was only in the early 1980s that Bill Follett and I decided to send a request to the ICZN to reinstate Carcharias because its rejection on nomenclatural grounds interfered with taxonomic work on the family (Compagno & Follett, 1986) [It wasn't that Eugomphodus was more difficult to pronounce than Carcharias, really John! Try Synodontaspis or Triglochis, much less the fossil taurus-group taxa Striatolamia, Jaekelotodus and Hispidaspis!].

To our astonishment the ICZN considered the request after a long hiatus with no word of its progress, agreed with our arguments, and reinstated Carcharias with the special endorsement that it is not to be given precedence over Odontaspis AGASSIZ, 1838, whenever the two are considered synonyms (ICZN, 1987). The decision was too late to include in the Princeton carcharhinoid book (Compagno, 1988), which was in press at the time and retained Eugomphodus, but not for the 1989 South African field guide or the 1990 megamouth paper in the NMFS symposium volume, which made the switch to Carcharias.

Thus there can be a return in part to the nomenclature of Rafinesque, Jordan & Evermann, and Bigelow & Schroeder in considering the sand tiger, ragged-tooth shark, or grey nurse shark as Carcharias taurus, with a circle taking us through Odontaspis taurus, Eugomphodus taurus, and Synodontaspis taurus. Placing the ferox group in Odontaspis follows current work in lamnoid paleontology and phyletics of lamnoids rather than neontological and paleontological tradition. The differences between living members of the two genera are extensive and impressive. Some of these differences are cited in Compagno (1984), Compagno & Follett (1986), and Compagno (1990).

As for Carcharias tricuspidatus, I'm inclined to list it as a tentative synonym of Carcharias taurus in the revised FAO shark catalog (tentatively scheduled for publication at the end of next year) for reasons discussed in part in the original 1984 FAO shark catalog.

Leonard Compagno