Ancient DNA from the extinct Haitian cave-rail (Nesotrochis steganinos) suggests a biogeographic connection between the Caribbean and Old World

Abstract

Worldwide decline in biodiversity during the Holocene has impeded a comprehensive understanding of pre-human biodiversity and biogeography. This is especially true on islands, because many recently extinct island taxa were morphologically unique, complicating assessment of their evolutionary relationships using morphology alone. The Caribbean remains an avian hotspot but was more diverse before human arrival in the Holocene. Among the recently extinct lineages is the enigmatic genus Nesotrochis, comprising three flightless species. Based on morphology, Nesotrochis has been considered an aberrant rail (Rallidae) or related to flufftails (Sarothruridae). We recovered a nearly complete mitochondrial genome of Nesotrochis steganinos from fossils, discovering that it is not a rallid but instead is sister to Sarothruridae, volant birds now restricted to Africa and New Guinea, and the recently extinct, flightless Aptornithidae of New Zealand. This result suggests a widespread or highly dispersive most recent common ancestor of the group. Prior to human settlement, the Caribbean avifauna had a far more cosmopolitan origin than is evident from extant species.

First genetic data for the critically endangered Cuban endemic Zapata Rail Cyanolimnas cerverai, and the taxonomic implications

“…Similar to the whole-mitochondrion analyses by Oswald et al (2021), our analyses of COI placed Nesotrochis outside Rallidae, separated from Cyanolimnas by some 45 million years (Fig. 1).…”

“…In line with Oswald et al (2021), Nesotrochis was recovered as a sister lineage to Sarothruridae (Fig. 1).…”

“…S2). We then obtained a larger set of 450 COI sequences of extant taxa within the order Gruiformes from GenBank, and additionally included sequence data from ancient DNA of the extinct Nesotrochis steganinos (Oswald et al 2021), because of its proposed close relationship to the extant taxa included in the analyses in combination with its recent extinction (Oswald et al 2021 S2). We further trimmed this dataset to a 962-bp region that maximized overall sequence coverage and fully overlapped the Zapata Rail COI sequence (see "Data availability").…”

Evolutionary history of New World crakes (Aves: Rallidae) with emphasis on the tribe Laterallini

“…Consequently, we suggest caution in the interpretation of the phylogenetic position of fossil taxa based on these morphological characters. Recent mitochondrial genome sequences of the Caribbean Island extinct rail Nesotrochis have shown that it is closer to the Sarothruridae and Aptornithidae than to the Rallidae (Oswald et al, 2021). However, Garcia‐R and Matzke (2021) included Nesotrochis in their ‘ Aramides ’ clade, a result that could have been influenced by the inadequacy of morphological data to clarify its placement (Livezey, 1998) or caused by their omission of data from the Sarothruridae and Aptornithidae.…”

Catalogue of Cuban fossil and subfossil birds

“…27 August 2019: morphology of the hypotarsus in Nesotrochis indicates it is not a Rallidae (Mayr 2019), but shares osteological characters with flufftails, Sarothruridae (Africa and New Guinea) and related taxa (Heliornithidae). 17 March 2021: mitochondrial genome analysis of N. steganinos Olson, 1974 (Hispaniola) corroborates that the genus is not a rallid (Oswald et al 2021), but a sister taxon to Sarothruridae and the extinct flightless Aptornithidae (New Zealand).…”