Nesophontidae Anthony, 1916

Morgan, Gary S., Macphee, Ross D. E., Woods, Roseina & Turvey, Samuel T., 2019, Late Quaternary Fossil Mammals From The Cayman Islands, West Indies, Bulletin of the American Museum of Natural History 2019 (428), pp. 1-81 : 12-13

Family Nesophontidae Anthony, 1916

REMARKS: Nesophontidae is a family of solenodonotan lipotyphlans, the only known representatives of which are species of the late Quaternary Antillean genus Nesophontes ( Whidden and Asher, 2001; Brace et al., 2016). The affinities of Nesophontes have been diversely treated in the century since the discovery of the first member of the genus (Anthony, 1916). Most authors have favored a close relationship to soricoids, usually on the basis of an apparently shared pattern of molar dilambdodonty (e.g., Saban, 1954; Van Valen, 1967), but others have discussed whether Nesophontes might instead be the sister taxon of Solenodon , another lipotyphlan restricted to the Caribbean but exhibiting molars that are morphologically zalambdodont (e.g., Gregory, 1920; McDowell, 1958; Asher and Sánchez-Villagra, 2005). This dispute was recently settled in favor of the latter hypothesis, on the basis of ancient DNA evidence collected from a 750 year old N. paramicrus specimen from Hispaniola (Brace et al., 2016). The closest known relatives of Nesophontes and Solenodon are probably Eocene and Oligocene insectivores in the family Geolabididae from North America ( Simpson, 1956; McDowell, 1958; MacFadden, 1980; Lillegraven et al., 1981; Morgan and Woods, 1986). Molecular dating indicates that the split between Solenodontidae and Nesophontidae occurred around 40 Ma. In view of their distinctiveness and antiquity within Lipotyphla , these families were recently placed in their own suborder, Solenodonota , by Brace et al. (2016). Their mutual divergence may have occurred on the North American mainland, in which case two invasions of the Greater Antilles by solenodonotans must be inferred. Alternatively, divergence may have occurred after initial colonization of the island arc by a joint ancestor, requiring only a single invasion ( Simpson, 1956; McDowell, 1958; MacFadden, 1980; Lillegraven et al., 1981; Morgan and Woods, 1986; Iturralde- Vinent and MacPhee, 1999). Nesophontes and Solenodon are the only two endemic genera of land mammals in the West Indies that are clearly of Nearctic origin. All other Antillean terrestrial mammals have explicitly South American or more general Neotropical affinities ( Morgan and Woods, 1986).

The type species and largest member of the genus, Nesophontes edithae , was originally described from Puerto Rican cave deposits (Anthony, 1916). It is also known from Amerindian archaeological sites on Vieques and the Virgin Islands ( Morgan and Woods, 1986; Quitmyer, 2003). Five species of Nesophontes have been described from Cuba: N. micrus Allen, 1917 , N. longirostris Anthony, 1919 , N. major Arredondo, 1970 , N. submicrus Arredondo, 1970 , and N. superstes Fischer, 1977 . Three species of Nesophontes have also been described from Hispaniola by Miller (1929): N. hypomicrus , N. paramicrus , and N. zamicrus . Nesophontes is unknown from Jamaica, Bahamas, or Lesser Antilles.

Considerable size variation exists within Puerto Rican samples of N. edithae , which was initially interpreted by Anthony (1916) as representing sexual dimorphism. As large-scale sexual dimorphism is unknown in other recent lipotyphlans, this variation was used as part of the original justification for erecting a new family to accommodate the species (Anthony, 1916). However, size variation in N. edithae has been subsequently interpreted as more likely to reflect allochronic plasticity, with specimens of varying sizes probably originating from different depositional horizons across the Late Quaternary (Choate and Birney, 1968; McFarlane, 1999). Condis Fernández et al. (2005) analyzed metrical and morphological variation in Cuban Nesophontes , and concluded that only two species could be supported, N. major and N. micrus , the latter incorporating all of the other nominal taxa. Importantly, these authors showed that size is a particularly labile character within Cuban Nesophontes and is therefore not a dependable basis for erecting species boundaries, especially when considered in isolation. Silva Taboada et al. (2007) went even further, suggesting that all previously diagnosed Cuban species of Nesophontes are in fact morphs of N. micrus . However, their subordination of all nominal taxa within a single species was made without any commentary, and they did not review the diagnostic value of the characters cited by Condis Fernández et al. (2005) for distinguishing N. micrus and N. major . The Hispaniolan species have not been subjected to revision in recent years, and the scale of intraspecific variation in Cuban Nesophontes raises the question whether these three species are truly distinct, or instead just size morphs of one or two variable species. Since this issue cannot be settled here, for the purposes of this study we retain Miller’s taxa as valid.

The previous existence of Nesophontes on Cayman Brac and Grand Cayman has been repeatedly noted in the literature (e.g., Patton, 1966; Varona, 1974; Morgan et al., 1980; Steadman and Morgan, 1985; Morgan and Woods, 1986; Morgan, 1994a), but no formal systematic determination of its status has ever been undertaken. Regrettably, the Cayman material is too fragmentary or otherwise damaged to make a morphometric treatment worthwhile.