Table 2 in Taxonomy, phylogeny, and diversity of the extinct Lesser Antillean rice rats (Sigmodontinae: Oryzomyini), with description of a new genus and species

Table 2. Condition of morphological characters for West Indian rice rat taxa
Character traitPennatomysMegalomysOligoryzomysSizeMediumLargeSmallPedal plantar padsUnknownHypothenar absent or vestigial, digitals largeHypothenar present, digitals smallNasals posterior extensionEven with maxillary–frontal– lacrimal suturePosterior to maxillary–frontal– lacrimal sutureEven with maxillary–frontal– lacrimal sutureLacrimal articulationEqual maxillary and frontalPrimarily with maxillaryEqual maxillary and frontalSupraorbital shapeSlightly convergent anteriorly with weak crestConvergent anteriorly with well-developed crestSquared, smooth marginsPosterior margin of zygomatic plateSlightly anterior to M1 alveolusApproximately even with M1 alveolusAnterior to M1 alveolusCarotid circulation patternUnknownIII*II*Anterior section of masseteric crests in ramusJoinedSeparatedSeparatedLabial accessory root on M1AbsentPresentUnknown†Roots on m233Unknown†Roots on m323Unknown†Anteromedian flexus on M1AbsentPresent, shallowPresent, deepMesofossette on M2SingleSingleDoublePosteroloph on M3AbsentPresentPresentAnterolophid on m2 and m3PresentPresentAbsent
Megalomys characters are based on Megalomys luciae and Megalomys desmarestii only.
*Pattern II, stapedial foramen present, sphenofrontal foramen absent; pattern III, stapedial foramen and sphenofrontal foramen absent.
†Other species of Oligoryzomys do not have a labial accessory root on M1, and have only two roots on m2 and m3.