Otaria flavescens (Shaw, 1800)

Lucero, Sergio, Rodríguez, Sara M., Teta, Pablo, Cassini, Guillermo & D’Elía, Guillermo, 2019, Solving a long-standing nomenclatorial controversy: designation of a neotype for the southern sea lion Otaria flavescens (Shaw, 1800), Zootaxa 4555 (2), pp. 296-300 : 297-299

Otaria flavescens (Shaw, 1800)

Synonyms: aurita Bechstein, 1800; byronia de Blainville, 1820 ; chilensis Muller, 1841; chonotica Philippi, 1892; fulva Philippi, 1892; godeffroyi Peters, 1866; hookeri Schlater, 1866; leoninus F.G. Cuvier, 1827; minor Gray, 1874; molossina Lesson and Garnot, 1826; mollosinus Lesson, 1827; pernettyi Lesson, 1827; pygmaea Gray, 1874; rufa Philippi, 1892; ulloae Tschudi, 1844; uraniae Lesson, 1827; velutina Philippi, 1892.

Neotype. MACN-Ma 23.26, Adult male, skull and mandible, almost without teeth, acquired by the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” on july 18th, 1923 (data on collector is missing) ( Fig. 2 ).

Type locality. San Sebastián (ca. -53.2979, -68.4512), Provincia de Tierra del Fuego, Antártida e Islas del Atlántico Sur, República Argentina ( Fig. 3 ).

Measurements of the neotype.- Condylobasal length = 346.4 mm; zygomatic width = 236.0 mm; braincase width = 120.5 mm; rostral length = 88.3 mm; rostral width = 100.0 mm; rostral height = 76.1 mm; postorbital constriction = 33.8 mm; mastoid width = 210.0; palatal length = 206.0 mm; palatal width = 55.0 mm; upper postcanine length = 94.0 mm; alveolus width of upper canine = 24.0 mm; length of dentary = 276.4 mm; coronoid height = 120.0; length of coronoid process = 89.0 mm; length of lower postcanine row = 81.0 mm;

Distribution. Otaria flavescens is distributed along the Atlantic and Pacific coasts, from the Galápagos Islands in Ecuador (Pacific) and southern Brazil (Atlantic) in the north, to the archipelago of Tierra del Fuego and Islas Malvinas in the south ( Aguayo and Maturana, 1973; Pine et al., 1978; Sielfeld, 1983; Bastida et al., 2007).

Emended morphological diagnosis. (modified from Brunner, 2003) A species of the family Otariidae characterized by the following combination of character states: skull robust; rostrum sloped and broad, specially between the canines; nasals short and broad; preorbital processes well developed; interorbital constriction wide; supraorbital processes robust, rounded-to-quadrate; palate long, reaching the hamular process of the pterygoid, and wide, with its lateral edges curved ventrally; posterior border of the palate nearly straight; zygomatic arches wide, planned dorsoventrally at the squamoso- jugular margin; mastoids heavy and long in adult males but more reduced in females; canines large and robust; sagittal crest most pronounced in adult males, extending along the frontal and increasing in height towards the occipital crest; occipital crest in males very robust, flaring dorsolaterally from the posterior margins of the sagittal crest; mandible heavy, particularly at the canine roots; coronoid process with a deep and long masseteric fossa (see Fig. 2 ).

Remarks: Usage of the name flavescens has some advantages in searches for bibliography and occurrence records over the usage of byronia . For example, a search in Google Scholar (https://scholar.google.com/; conducted on November 11, 2018) for Otaria flavescens retrieved 3550 results against 1800 for Otaria byronia . Similarly, there are 3704 documented occurrences for Otaria byronia in GBIF (Global Biodiversity Information Facility; accessed on November 11, 2018) against 552 for O. byronia .

The type locality of Phoca byronia was defined as “…the island of Tinian …Cette île est l’une des îles Marianiies ou des Larrons, située à l’est des Phillipines ou par le 15° de latitude méridionale et le 215° de long. méridionale de Greenwich” (de Blainville, 1820) (= Northern Mariana Islands in the northeastern Pacific); however, as have been discussed by several authors (e.g., Rodriguez & Bastida, 1993), this is likely an error, since this island is far away from the known distribution of this species and of any other otarid. Scheffer (1958), based on the discussion provided by Allen (1905) and Hamilton (1934), stated that the holotype of byronia probably came from the Strait of Magellan or Islas Juan Fernandez. This is a large area that encompasses both Atlantic and mostly Pacific waters, between 33.90° S, 80.70° W and 52.60° S- 68.30 ° W. With the evidence at hand, it is not possible to determine the exact provenance of the animal studied by de Blainville. Considering the uncertainty on the geographic origin of the type of byronia and given that it is lost ( Rodríguez and Bastida, 1993), the selection of a neotype for this taxon is also warranted; this action would allow ending the ambiguity on to which populations this taxonomic form applies. Having said that, we prefer to not undertake this nomenclatorial action and leave it for a future taxonomic study aimed to test the putative distinction between Peruvian and northern Chilean populations and Atlantic and southern Chilean populations, to which currently the taxonomic name flavescens applies.

We end this contribution mentioning the well-known fact that even for well-studied and charismatic large mammals, as the pinnipeds, nomenclatorial and taxonomic issues are still pending of resolution. As such, we call for continuing support of collection-based research aimed to characterize the biodiversity at the species level.

Figures

FIGURE 2. Neotype of Phoca flavescens Shaw, 1800 (MACN-Ma 23.26). Scale = 50mm.

FIGURE 3. Map of southern South America, depicting the restricted type locality (red star) of Phoca flavescens Shaw, 1800 (MACN- Ma 23.26). The blue shadow in the inset South American map indicates the distributional range of Otaria flavescens.