Fregetta

Bretagnolle, Vincent, Flood, Robert L., Gaba, Sabrina & Shirihai, Hadoram, 2022, Fregetta lineata (Peale, 1848) is a valid extant species endemic to New Caledonia, Bulletin of the British Ornithologists’ Club 142 (1), pp. 111-130 : 117-119

Phylogenetic relationships between Fregetta storm petrels

Recent genetic work shed light on the Fregetta complex, but also added uncertainties and confusion. These have confirmed that live F. maoriana and the three F. maoriana specimens are the same taxon ( Robertson et al. 2011). They are distinct from and not close to Oceanites and lie within Fregetta ( Robertson et al. 2011, 2016). This is supported by evidence from Mallophaga: Philoceanus fasciatus , a species found on both F. tropica and F. grallaria , has been collected on F. maoriana , and is morphologically very different from both Philoceanus robertsi , parasitic on Oceanites oceanicus , and Philoceanus garrodiae , parasitic on Grey-backed Storm Petrel Garrodia nereis ( Stephenson et al. 2008b) .

Three studies provide Fregetta phylogenetic trees; based on either short (c.500 bp; Cibois et al. 2015), long (960 bp; Robertson et al. 2016), or complete cyt- b sequences ( Robertson et al. 2011); as well as seventh intron of beta Fib ( Robertson et al. 2011, 2016). This diversity of genetic material led to contrasting conclusions. F. maoriana was closer to F. tropica than F. grallaria in both complete cyt- b and nuclear intron ( Robertson et al. 2011), closer to F. tropica than F. grallaria in short cyt- b ( Cibois et al. 2015), but closer to F. grallaria in long cyt- b and closer to F. tropica in nuclear intron ( Robertson et al. 2016). In addition, F. lineata AMNH 194110 was sequenced and results indicate that it diverges from F. maoriana and, based on partial cyt- b sequence (557 bp), is more closely related to F. grallaria , especially F. [g.] titan, than to F. tropica ( Cibois et al. 2015, Robertson et al. 2016). A matter of note, Robertson et al. (2016) commented that Cibois et al. (2015) were wrong to include NHMUK 1953.55.101 (collected on Gough Island, South Atlantic, held at the Natural History Museum, Tring) as F. grallaria . However, the sequence was taken from Robertson et al. (2011), as recorded in GenBank, so the original error is owned by the latter.

Our findings show that USNM 15713 and AMNH 194110 are the same taxon, F. lineata , based on morphometrics, although no genetic data are available for the USNM specimen. Interestingly, the Brisbane specimen QM 14391 was sequenced and clumped with F. [g.] titan ( Robertson et al. 2011), as did the Ua Pou specimen AMNH 194110 ( Cibois et al. 2015), supporting the case for aggregating them. Incidentally, whilst QM 14391 is labelled F. tropica, Robertson et al. (2016) treated it as F. grallaria , presumably because sequences clade with F. grallaria rather than F. tropica . However, systematics of the group are complicated by the opaque taxonomy of the genus Fregetta itself ( Howell 2010, 2012), with more than 20 different names proposed for these birds, and the complex situation in Tristan da Cunha, South Atlantic ( Brooke 2004, Howell 2012, Flood & Fisher 2013). In particular, taxonomy of the F. grallaria and F. tropica complexes are not resolved ( Crochet 2008, Howell 2010, 2012, Robertson et al. 2016). That said, there is consensus that the four Fregetta taxa ( F. grallaria , F. tropica , F. lineata and F. maoriana ) form a monophyletic clade, based on mtDNA and nuclear DNA, albeit a single gene in both cases ( Robertson et al. 2011, Cibois et al. 2015, Robertson et al. 2016). This clade is distinct from Oceanites and supports the generic denomination Fregetta .