Independent evolutionary histories in allopatric populations of a threatened Caribbean land mammal

Abstract

Aim To determine the evolutionary history, relationships and distinctiveness of allopatric populations of Hispaniolan solenodon (Solenodon paradoxus), a highly threatened Caribbean 'relict' mammal, to understand spatio-temporal patterns of gene flow and the distribution of diversity across complex large island landscapes and inform spatial conservation prioritization.Location Historical and modern-day solenodon specimens were analysed from sampling localities across Hispaniola, representing this geotectonically complex island's distinct northern, south-eastern and south-western biogeographic provinces.Methods We successfully amplified mitochondrial cytochrome b and control region sequences from 34 solenodon samples. Bayesian phylogenetic analyses were applied to assess the relationship between these sequence data, and coalescent simulation and approximate Bayesian computation were used to identify which model of solenodon intra-island demographic history best explains the observed patterns of variation. We also conducted morphometric analysis of 110 solenodon specimens to investigate whether allopatric Hispaniolan populations can be differentiated using craniodental characteristics.Results Unique haplotypes were identified in solenodon samples from each biogeographic region, with no haplotype sharing between regions. Higher marginal posterior probability values were found for a three-population model comprising allopatric northern, south-eastern and south-western Hispaniolan populations, with exceptionally low migration rates inferred between all populations, indicating that they are genetically isolated. Modal estimates of long-term effective female population size are extremely low for south-western and south-eastern populations. Morphometric differentiation is observed between all three populations.Main conclusions Evolutionary differentiation of Hispaniolan solenodons into three distinct populations is congruent with phylogenetic patterns observed in several other Hispaniolan species, with population isolation possibly associated with past marine transgression. We interpret these populations as distinct subspecies, with the two genetically impoverished southern subspecies particularly vulnerable to environmental change. Our improved understanding of Hispaniolan solenodon evolutionary history provides an important baseline for identifying wider patterns of intra-island diversification and prioritizing conservation attention for evolutionarily significant populations.

Using the past to contextualize anthropogenic impacts on the present and future distribution of an endemic Caribbean mammal

“…Turvey et al. () report estimates of effective population size as approximately 3000 for S. paradoxus paradoxus in the northern Dominican Republic, yet only approximately 30 each for the other 2 groups. These genetic data, combined with our SDM results, suggest urgent attention is required to ensure the survival of these 2 populations in the future and contribute to a discussion for the role of corridors.…”

“…It maintains the potential for gene flow within populations (or putatitive subspecies) in the Dominican Republic (that is, between S. paradoxus woodi and S. paradoxus paradoxus) while effectively dooming S. paradoxus haitensis to low population sizes, inbreeding, and extinction. Turvey et al (2016) report estimates of effective population size as approximately 3000 for S. paradoxus paradoxus in the northern Dominican Republic, yet only approximately 30 each for the other 2 groups. These genetic data, combined with our SDM results, suggest urgent attention is required to ensure the survival of these 2 populations in the future and contribute to a discussion for the role of corridors.…”

“…Recent genetic studies suggest the 3 allopatric populations of S. paradoxus represent 3 subspecies: S. paradoxus paradoxus in northeastern Dominican Republic, S. paradoxus woodi in southwestern Dominican Republic, and S. paradoxus haitensis remaining only on the Tiburon peninsula in Massif de la Hotte (Turvey et al 2016;Brandt et al 2017;Grigorev et al 2018) (Fig. 1).…”

“…Quaternary fossil records document an island‐wide distribution for solenodons (Ottenwalder ), yet today's distribution consists of 3 allopatric populations scattered across fragmented habitat; the remnant population in Haiti is entirely isolated and nearly extinct (Turvey et al. ). Although genetic data for this species are limited and lack historic baselines, they suggest S. paradoxus may have multiple subspecies facing varying levels of genetic impoverishment (Brandt et al.…”

“…The decline of S. paradoxus has been linked to predation by village dogs and deforestation inside and outside nationally protected landscapes (Rupp & Leon 2009;Turvey et al 2014). Quaternary fossil records document an island-wide distribution for solenodons (Ottenwalder 2001), yet today's distribution consists of 3 allopatric populations scattered across fragmented habitat; the remnant population in Haiti is entirely isolated and nearly extinct (Turvey et al 2016). Although genetic data for this species are limited and lack historic baselines, they suggest S. paradoxus may have multiple subspecies facing varying levels of genetic impoverishment (Brandt et al 2017;Mychajliw 2017;Grigorev et al 2018).…”