Taxonomy of Oceanites

Here we re-evaluate the systematics of Oceanites based on a phylogenetic tree with a complete representation of each taxon described for Oceanites, six subspecies, and a new population from the central Andes of Chile that we propose as a new taxon. We included specimens sampled close to type localities and a broad representation of biometric data from museums. Our sampling suggests that each formerly described subspecies must be elevated to a species category following the GLSC (de Queiroz 1998, 1999, 2007). Our results show that subspecies within two of the currently recognized Oceanites species are polyphyletic. This new phylogenetic hypothesis suggests a new linear sequencing within the genus Oceanites. Following the criteria of Remsen et al. (2023); this should be as follows:

Oceanites chilensis (Mathews 1934) —Fuegian Storm-Petrel

Oceanites exasperatus (Mathews 1912) —Antarctic Storm-Petrel

Oceanites gracilis (Elliot 1859) —Elliot’s Storm-Petrel

Oceanites pincoyae (Harrison et al. 2013) —Pincoya Storm-Petrel

Oceanites barrosi sp. nov. —Andean Storm-Petrel—Golondrina de mar andina (Chilean name)

Oceanites galapagoensis (Lowe 1921) —White-vented or Lowe’s Storm-Petrel

Oceanites oceanicus (Kuhl 1820) —Subantarctic Storm-Petrel

Note that English names used here are those which are officially used now or have been suggested in the recent literature, and these include eponyms. We are using these for convenience of communication and would not oppose the use of other names which may be more informative of the geographic or ecological history of these species.

The species O. exasperatus Mathews, 1912 has the type locality of “at sea, off New Zealand ” and is described as larger than oceanicus. Currently, all Antarctic populations breeding south of the Antarctic Convergence are classified as the larger exasperatus (Roberts 1940; Beck & Brown 1972; Pacha et al. 2023). However, given the geographical distance, the phylogenetic relationships of other populations of O. exasperatus present in Antarctica should be reviewed, particularly in southern Africa and Oceania. Since Wilson’s Storm-Petrel is the English name assigned to O. oceanicus, we suggest using Antarctic Storm-Petrel for O. exasperatus. Murphy & Beck (1918) as well as Bourne (1964b) argued that measurements are variable between southern Atlantic breeding oceanicus and exasperatus, and they suggested that all populations should be treated as oceanicus. Kuhl (1820) named Procellaria oceanica from a drawing of a specimen captured near the mouth of the La Plata River during Cook’s first expedition (Bourne 1964b), the type locality having subsequently been designated by Murphy & Beck (1918) as South Georgia. The nominate subspecies is, therefore, the breeding form in subantarctic islands including South Georgia, Falkland/ Malvinas, and Kerguelen. The name parvus (Falla 1937) exists for populations on Kerguelen Island, but apart from a mention in Roberts (1940), this name has not been used subsequently. Given that Wilson’s Storm-Petrel is the English name that has been applied to multiple taxa in our current study, and the breeding distribution of oceanicus is in subantarctic islands, we consider that the most appropriate name for O. oceanicus s.s. is Subantarctic Storm-Petrel.

The Elliot’s Storm-Petrel has two allopatric populations, nominate gracilis in the Humboldt Current region and the larger and paler form galapagoensis of the Galapagos (Lowe 1921). For O. galapagoensis we adopt the English name used by Howell & Zufelt (2019) for this population, Lowe’s Storm-Petrel. This may require a name change which will require some thought; although Galapagos Storm-Petrel would be obvious, this has been applied in the past to Hydrobates tethys. Fuegian breeding populations of O. chilensis are smaller than oceanicus and named chilensis based on a specimen from Wollaston Island, Chile (Mathews 1934). The complex nomenclatural history is noted in Murphy (1936) and Sheard (1943), and clarified in Palma et al. (2012a, b).

Until this work, there was no name for central Chilean populations (Mathews 1934; Murphy 1936; Sheard 1943; Spear & Ainley 2007; Palma et al. 2012a; Howell & Zufelt 2019). Oceanites barrosi sp. nov. is similar to O. pincoyae and O. chilensis. Differences between these species include the extension of white across the belly and underwing coverts. The holotype specimens were previously identified as O. oceanicus chilensis but were re-identified as O. gracilis gracilis (see Fig. 5) by M. Marin on 4 May 2000 (H.-S. Young, pers. comm.). The extension of white on the belly is a trait that has historically been attributed to O. gracilis. Still, newly reviewed material reveals this to be a trait shared to a greater or lesser degree among gracilis, galapagoensis, pincoyae, and barrosi sp. nov. Our results and new taxonomic arrangement lead to the urgency of discovering the breeding sites of pincoyae, galapagoensis, and barrosi sp. nov. to understand their population sizes and conservation status. It is eye-opening that three of the seven species in Oceanites have not yet had their nests described. In all the proposed taxa, the conservation categories should be re-assessed since population sizes and breeding sites are still unknown for several newly recognized species.