A new study by Turvey and colleagues (2025), just published in iScience, re-examines the Puerto Rican island-shrew Nesophontes edithae from the classic Morovis caves using precise radiocarbon and U-series dating, morphometrics of jaws and limb bones, and carbon-isotope analyses of tooth enamel to document an earlier, smaller morph in more open, savanna-like habitats and a later, larger morph in closed forests between about 50,000 years ago and the mid-Holocene. Recent work on the Puerto Rican Nesophontes therefore complements, rather than contradicts, the Cuban record, and together both datasets help refine our view of how this extinct group lived and evolved in the Greater Antilles since the Ice Age.
A brief introduction to an odd little mammal
Nesophontes were small, shrew-like mammal endemic to the Greater Antilles. These 'island-shrews' belonged to the order Eulipotyphla, the same broader group that includes living shrews, moles, hedgehogs, and their relatives. Fossils show that Nesophontes were likely nocturnal, semi-fossorial insectivores, and possibly venomous. Each large island had its own endemic forms: three species are currently recognized in Cuba (N. micrus, N. major, N. longirostris), three in Hispaniola (N. paramicrus, N. hypomicrus, N. zamicrus), one in Puerto Rico (N. edithae), and one in the Cayman Islands (N. hemicingulus).
The history of their discovery is closely tied to the American Museum of Natural History in New York. Harold E. Anthony described Nesophontes edithae in 1916 from material collected near Morovis, Puerto Rico. The type specimen was found in Cueva Clara by his wife, Edith I. Anthony, whose name the species still carries. In 1917, Glover M. Allen described N. micrus from material collected in Matanzas by Carlos de la Torre. Later, Anthony described N. longirostris from a cave in Daiquirí, southeastern Cuba. These early discoveries laid the groundwork for more than a century of work on this unusual mammal.
In recent years, new biomolecular methods have greatly improved our understanding of Nesophontes evolution. Collagen sequence analyses (proteomics) published by Buckley et al. (2020) helped clarify the relationships within the group and re-confirmed that Nesophontes and the living solenodons form sister lineages within Solenodontidae-Solenodonota. For the Cuban material, that molecular work showed that most specimens fall into two main collagen lineages corresponding to a smaller morph N. micrus and a larger morph N. major, with the large, long-snouted N. longirostris forming a close relative of N. major rather than a separate deep lineage. These proteomic results provide an independent framework that is consistent with, and helps to refine, the species limits later formalized on morphological grounds by Orihuela (2023).
Against this background, two recent lines of research help refine the picture: Turvey and colleagues’ 2025 study of N. edithae in Puerto Rico, and Orihuela's 2023 revision of the Cuban species.
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| Nesophontes edithae holotype AMNH 14174 (female?) From original photograph published by Anthony (1916). |
The Puerto Rican material is firmly anchored in time. Radiocarbon dating of associated charcoal and U-series dating of bones show that the small morph spans at least ~50,000–16,000 years before present, whereas the large morph appears rapidly around 13,500 years ago and continues into the middle Holocene. Turvey et al. then add stable carbon isotopes from tooth enamel to this framework. The small, older morph has more positive δ¹³C values (mean −7.9‰), while the large, younger morph shows more negative values (mean −10.3‰). This difference is interpreted in terms of habitat: the small morph is associated with more open savanna-type environments rich in C₄ grasses, typical of the Late Pleistocene, whereas the large morph is associated with more closed, C₃-dominated forests typical of Holocene Puerto Rico. In this setting, size change is explicitly tied to a well-constrained climatic and vegetational transition. Because the bones have lost almost all organic content, neither collagen nor DNA could be recovered, and delicate elements such as pelvises were not analyzed molecularly or morphologically; their conclusions rest on stratigraphy, morphometrics, and enamel δ¹³C.
Choate and Birney’s classic paper, “Sub-recent Insectivora and Chiroptera from Puerto Rico, with the description of a new bat of the genus Stenoderma”, was published in 1968 in the Journal of Mammalogy. In that work they already noted that the marked size variation in Puerto Rican Nesophontes could reflect differences between cave assemblages of different ages (a “chrono-temporal” effect), rather than only individual or sexual variation. Turvey et al.’s new study effectively tests and refines that idea. By tying the small and large N. edithae morphs to separate, radiometrically dated Late Pleistocene and Holocene layers at Morovis, and showing that they do not overlap in time while also occupying different isotopic (habitat) niches, their results are consistent with the chrono-temporal interpretation outlined by Choate and Birney, but go further by rejecting the need for strong sexual dimorphism and by quantifying the timing and environmental context of the size shift.
The Cuban story: three species, each with incipient sexual dimorphism
By contrast, recent work on Cuban taxa (Orihuela et al., 2020), and specially the most recent revision (Orihuela 2023) has been explicitly island-wide and taxonomic in scope. Following one species through time at a single locality, that study assembled and statistically analysed large numbers of Nesophontes specimens—thousands of bones—from several carefully radiocarbon dated beds and specimens. Where layers could be assigned to the same age, specimens from those single-age horizons were compared directly. Those results were then contrasted with material from older and younger units in the same sites, and finally with samples from other regions of the island, but in some cases precise chronological control was not available. This stepwise approach allowed Orihuela to ask both how many species were present and how much variation occurred within each species across space and, where possible, through time.
Morphologically, the Cuban revision re-examines N. micrus, N. major, and N. longirostris based on a large sample integrating cranial, dental, petrosal, endocranial, and postcranial measurements. Statistical distributions of key variables such as maxillary toothrow length, breadth across canines, and femoral length are distinctly bimodal when all Cuban Nesophontes are pooled, and do not fit a single Gaussian population, supporting the recognition of at least two Cuban species rather than extreme intraspecific variation. Within this framework, body mass is estimated with several independent methods (molar area, cranial length, limb shaft circumference). For N. micrus, the range is ~37–56 g, and for N. major ~33–67 g, with N. longirostris slightly larger than N. major. These values are consistent with a clade of small, mouse-to-rat sized insectivores and fall below the values obtained for N. edithae in Puerto Rico, in line with the long-standing view that N. edithae was among the largest members of the genus.
In recent years, new biomolecular methods have also improved our understanding of Nesophontes evolution. Collagen sequence analyses (proteomics) published by Buckley et al. (2020), with Orihuela as co-author, clarified relationships within the group and confirmed that Nesophontes and the living solenodons form sister lineages. For the Cuban material, that molecular work showed that most specimens fall into two main collagen lineages corresponding to N. micrus and N. major, with the large, long-snouted N. longirostris closely allied to N. major rather than representing a completely separate deep lineage. These proteomic results provide an independent framework that is consistent with, and helps to refine, the species limits formalized on morphological grounds by Orihuela (2023).
Both studies also incorporate stable isotopes, but with different substrates, resolutions, and goals. Turvey et al. analyse δ¹³C in tooth apatite, which is robust to diagenesis and directly reflects the carbon-isotope composition of plants at the base of the local food web. Their key signal is a statistically significant shift in enamel δ¹³C between the small and large morphs that closely tracks the Pleistocene–Holocene transition from open to closed habitats. Isotopes in this case are used primarily to support a chronoclinal habitat shift already suggested by the dated stratigraphy.
In Cuba, the isotopic work is an initial attempt to understand diet and habitat in two species that are already known to be sympatric (Orihuela et al., 2020; Orihuela, 2023). Collagen δ¹³C and δ15N values are reported for N. micrus, N. major, and Solenodon cubanus from several well-dated Holocene cave deposits. Carbon values for Cuban Nesophontes span roughly −20‰ to −9‰, implying a mixture of C₃ and C₄ resources, and hence use of both open and closed environments. When plotted against body size and compared with Solenodon, the data suggest that N. major was slightly more associated with shaded, closed habitats (more negative δ¹³C), whereas N. micrus tended toward more open grassland–savanna conditions (more positive δ¹³C). At the same time, the isotope data indicate that both species foraged across a heterogeneous landscape of mixed and riverine woodland interspersed with more open areas. he results presented by Orihuela et al. (2020) and Orihuela (2023) are best regarded as a first baseline for Nesophontesisotope ecology in Cuba, to be refined as larger and better time-constrained samples become available; the aim was to establish this baseline to be built upon later, rather than to provide a definitive picture.
Paleoart reconstruction of Nesophontes major by Adrian Tejedor (C)
Different islands, complementary stories?
The two papers reach different conclusions about the role of sexual dimorphism in explaining size variation, but under different empirical conditions. In Puerto Rico, Turvey et al. test the long-standing hypothesis that the size disparity in N. edithae reflects strong sexual size dimorphism. They find that within each stratigraphic unit the size distributions of their largest measurement series are unimodal, and that small and large morphs never co-occur in the same temporal horizon at the Morovis sites. Combined with the isotopic and chronological evidence for distinct palaeoenvironments, they interpret the small and large morphs as allochronic populations tied to different climatic and habitat regimes, and conclude that their results refute the earlier hypothesis of pronounced sexual dimorphism in Puerto Rican nesophontids. Because pelvises and other delicate postcranial elements are not preserved in sufficient numbers or investigated, their analysis appropriately does not include on pelvic anatomy.
In Cuba, the situation is more complex. The revision shows that N. micrus and N. major form two morphometrically distinct clusters at the species level, but also that within each species there is low, but detectable, morphometric variation that is consistent with modest sexual size dimorphism. Finite mixture analyses of selected cranial, petrosal, humeral, and femoral measurements suggest two overlapping subgroups per species with an average male:female ratio of about 1:1.03, similar to values reported for N. edithae femora by McFarlane (1999). Pelvic morphology shows additional differences: more robust morphotypes have more curved sciatic notches and thicker, rounder and more angost pubic symphyses than gracile morphotypes, patterns interpreted as male and female respectively. These pelvic contrasts parallel differences in humeral and femoral robustness: robust morphotypes have thicker shafts, larger femoral heads and more strongly marked muscle attachment scars, whereas gracile morphotypes are smaller and lighter. Orihuela (2023) emphasizes that these differences are modest and that Cuban Nesophontes “do not display substantial sexual size dimorphism” overall, with sex-linked variation treated as just one part of the size range within each species. This naturally raises the question of which morphotype is male and which is female: Anthony (1916) assumed the larger form was male, but the Cuban data do not require that, and the reverse could just as well be true. Resolving this would require independent sexing: for example, genetic or chromosomal markers in suitable material, to see who caries the female or male chromosomes.
Chronologically, the Puerto Rican and Cuban records complement each other. Turvey et al. work with a vertical, high-resolution Late Pleistocene–Holocene sequence at a single locality, and are able to document a relatively rapid size shift (on the order of three millennia) against a well-dated climatic backdrop. The Cuban data, in contrast, are dominated by late Holocene cave assemblages spanning roughly the last two millennia, with emphasis on spatial variation among sites and co-occurrence of species rather than on long-term chronoclinal trends. The isotope section of the Cuban work explicitly highlights temporal averaging and seasonal effects as potential complications, and calls for larger, stratigraphically constrained datasets to explore diachronic patterns in more detail.
Taken together, both studies point to a picture in which Nesophontes were neither ecologically rigid nor morphologically static. In Puerto Rico, a single lineage (or closely related lineages) shows large, environmentally correlated changes in body size and habitat use through the Late Quaternary, without evidence for strong sexual dimorphism driving the pattern. In Cuba, two smaller-bodied species coexist in Holocene landscapes, partitioning habitats and resources in subtler ways, with only modest sex-linked size differences within each taxon.
The methods are also complementary: Turvey et al. combine enamel isotopes with precise dating to frame a local chronoclinal story, while the Cuban revision uses extensive morphometrics, pelvic anatomy, collagen isotopes, and broader geographic coverage to refine taxonomy and ecological reconstruction.
Taken together, these differences also remind us that Cuba and Puerto Rico do not share the same geological or environmental history. Island size, topography, climate trajectories, and habitat mosaics have all differed through the Late Quaternary, and it is plausible that Nesophontes did not play exactly the same ecological roles or follow identical evolutionary paths on each island. At the same time, the present records are still incomplete and unevenly sampled, so these contrasts are best viewed as indications that island context matters for Nesophontes evolution, rather than as proof of any single evolutionary scenario. Future work will be needed to test how far these island-specific patterns really extend.
Conclusions
The key message is that these “island shrews” were dynamic components of Antillean ecosystems, tracking environmental change over tens of thousands of years and partitioning habitats at fine scales, long before human arrival. The Puerto Rican and Cuban records do not contradict each other; rather, they describe different facets of the same lineage’s history under different island contexts, and both leave open important questions that will be addressed as new material and methods become available.
Cited Literature
Turvey, S. T., Lamb, A. L., Rye, P., Vale Nieves, A., Cooper, J. H., & van Calsteren, P. 2025. Major body size change in an extinct tropical island mammal associated with glacial–interglacial environmental shifts. iScience 113968, in press. https://doi.org/10.1016/j.isci.2025.113968 Cell+1
Orihuela León, J. 2023. Revision of the extinct island-shrews Nesophontes (Mammalia: Eulipotyphla: Nesophontidae) from Cuba. Journal of South American Earth Sciences 130, 104544. https://doi.org/10.1016/j.jsames.2023.104544ResearchGate
Orihuela, J., Pérez Orozco, L., Álvarez Licourt, J. L., Viera Muñoz, R. A., & Santana Barani, C. 2020. Late Holocene land vertebrate fauna from Cueva de los Nesofontes, western Cuba: Stratigraphy, chronology, diversity, and paleoecology. Palaeontologia Electronica 23(3), a57. https://doi.org/10.26879/995 Palaeontologia Electronica
Buckley, M., Harvey, V. L., Orihuela, J., Mychajliw, A. M., Keating, J., Almonte Milán, J. N., Lawless, C., Chamberlain, A. T., Egerton, V. M., & Manning, P. L. 2020. Collagen sequence analysis reveals evolutionary history of extinct West Indies Nesophontes (“island-shrews”). Molecular Biology and Evolution 37(10), 2931–2943. https://doi.org/10.1093/molbev/msaa137 PMC
Choate, J. R., & Birney, E. C. 1968. Sub-Recent Insectivora and Chiroptera from Puerto Rico, with the description of a new bat of the genus Stenoderma. Journal of Mammalogy 49(3), 400–412. Nature
McFarlane, D. A. 1999. A note on dimorphism in Nesophontes edithae (Mammalia: Insectivora), an extinct island-shrew from Puerto Rico. Caribbean Journal of Science 35, 142–143. BioMed Central
Anthony, H. E. 1916. Preliminary diagnosis of an apparently new family of insectivores. Bulletin of the American Museum of Natural History 35, 725–728.
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