Ancient DNA of the extinct Jamaican monkey Xenothrix reveals extreme insular change within a morphologically conservative radiation

Abstract

The insular Caribbean until recently contained a diverse mammal fauna including four endemic platyrrhine primate species, all of which died out during the Holocene. Previous morphological studies have attempted to establish how these primates are related to fossil and extant platyrrhines, whether they represent ancient or recent colonists, and whether they constitute a monophyletic group. These efforts have generated multiple conflicting hypotheses, from close sister-taxon relationships with several different extant platyrrhines to derivation from a stem platyrrhine lineage outside the extant Neotropical radiation. This diversity of opinion reflects the fact that Caribbean primates were morphologically extremely unusual, displaying numerous autapomorphies and apparently derived conditions present across different platyrrhine clades. Here we report ancient DNA data for an extinct Caribbean primate: a limited-coverage entire mitochondrial genome and seven regions of nuclear genome for the most morphologically derived taxon, the Jamaican monkey Xenothrix mcgregori. We demonstrate that Xenothrix is part of the existing platyrrhine radiation rather than a late-surviving stem platyrrhine, despite its unusual adaptations, and falls within the species-rich but morphologically conservative titi monkey clade (Callicebinae) as sister to the newly recognized genus Cheracebus. These results are not congruent with previous morphology-based hypotheses and suggest that even morphologically conservative lineages can exhibit phenetic plasticity in novel environments like those found on islands. Xenothrix and Cheracebus diverged ca. 11 Ma, but primates have been present in the Caribbean since 17.5-18.5 Ma, indicating that Caribbean primate diversity was generated by multiple over-water colonizations.biogeography | Callicebus | extinct mammal | island evolution | phylogeny

Craniodental Allometry, Prenatal Growth Rates, and the Evolutionary Loss of the Third Molars in New World Monkeys

“…Third molar loss is exceptionally rare in primates (e.g., Swindler, ). Outside of extant callitrichids, one fossil platyrrhine, Xenothrix , is the only other example of evolutionary third molar loss in primates with debates about the phylogenetic placement of this extinct genus ongoing (MacPhee and Horowitz, ; Cooke et al, , Woods et al, ). Debates center around orbital shape and dental morphology in these two taxa, but many studies agree that the dental formulas shared between Xenothrix and extant callitrichids are convergent (Rosenberger, ; Rosenberger et al, ; MacPhee and Horovitz, ).…”

Rapid size change associated with intra-island evolutionary radiation in extinct Caribbean “island-shrews”

“…Despite adverse preservational conditions for ancient biomolecules in Caribbean environments, we were able to recover aDNA successfully from the extinct Hispaniolan island-shrew Nesophontes zamicrus, the smallest known non-volant endemic Caribbean land mammal [14]. This is only the second extinct Caribbean eulipotyphlan species for which genomic data are available, and our data represent some of the first aDNA sequences that have been recovered for any extinct vertebrates known from the rich Holocene subfossil record of the Greater Antilles [78,79].…”

Evolutionary and phylogenetic insights from a nuclear genome sequence of the extinct, giant ‘subfossil’ koala lemurMegaladapis edwardsi

“…Paleogenomic approaches have immense potential for helping to resolve phylogenetic relationships and for insights into the evolutionary biology of now-extinct taxa and ancestral clades 53 . Our study follows the recent analysis of a nuclear genome sequence from a ~5,800 years BP baboon (extant Papio ursinis ) 54 , the sequencing of a mitochondrial genome and five nuclear genes from an extinct Caribbean monkey ( Xenothrix mcgregori ) 55 , and prior mitochondrial DNA sequencing studies of multiple extinct subfossil lemur species 4–7 . In addition to paleogenomics, we are following continuing developments in the field of paleoproteomics 56 for similar insights from samples with inadequate ancient DNA preservation, including those considerably older.…”