Natalus jamaicensis (Goodwin, 1970)

TEJEDOR, ADRIAN, TAVARES, VALERIA DA C. & SILVA-TABOADA, GILBERTO, 2005, A Revision of Extant Greater Antillean Bats of the Genus Natalus, American Museum Novitates 3493 (1), pp. 1-23 : 12-21

Natalus jamaicensis (Goodwin), 1959

Figures 2–4

Natalus major jamaicensis Goodwin, 1959 . Natalus stramineus jamaicensis Linares, 1971 .

HOLOTYPE: AMNH 182000 , skull and skin in fluid, collected by C. B. Lewis in St. Clair Cave (locality 1 in the appendix), St. Catherine Parish, Jamaica on 5 March 1954. The skull is complete, and the skin is in good condition.

DISTRIBUTION: Jamaica, known to be extant at the type locality only (fig. 5) .

DIAGNOSIS: A relatively large representative of Greater Antillean Natalus with a long forearm (44.1–44.8 mm) relative to its skull length (17.4–18.1 mm); ear tip pointed, with a shallow notch on the outer margin of ear; point of flexion between rostrum and braincase dorsal to anterior edge of orbit; braincase rising abruptly from rostrum, with an angle greater than 608 between dorsal plane of rostrum and frontal plane of forehead; braincase rounded in dorsal profile, with breadth almost as great as length; postorbital constriction narrow, its sides almost parallel; maxillary distinctly concave above molars; one pair of small palatal fenestrae near the posterior edge of palate; basisphenoid pits shallow and almost imperceptible; posterior edge of ascending ramus of mandible straight and vertical, forming an angle close to 908 with basal plane of dentary, and lacking notch below condyloid process ( tables 2 , 3).

DESCRIPTION: Natalus jamaicensis has a long forearm (44.0–47.0 mm; P, 0.001, compared to Natalus major and Natalus primus ) but a relatively small skull (greatest skull length smaller than that of N. primus , P, 0.001; table 2 ; fig. 6). Its ears are large (20.2–21.2 mm). No significant secondary sexual dimorphism in size was found in our sample of N. jamaicensis .

The hair of Natalus jamaicensis is long, lax, dense, and slightly woolly. The dorsal hairs are longer (9–11 mm) than the ventral hairs (6–7 mm). The dorsal hairs are bicolored, with bases lighter than tips, and the ventral hair is also slightly bicolored, with bases darker than tips. The dorsal hair bases are buff and the tips are light sepia to tawny olive. The ventral hair bases are buff and the tips are pale pinkish­buff. Dorsally, there is a faint lighter­colored band across the shoulders. The pelage extends slightly into the plagiopatagium, dorsally to 6 mm, and ventrally to 10 mm. The uropatagium is sparsely furred in microscopic view. There is a sparse fringe of hairs along the free edge of the uropatagium.

The muzzle is long and dorsoventrally flattened. The small, oval nostrils open ventrolaterally. In ventral view, the tip of the muzzle, between the nostrils, projects slightly be­ yond the upper lip. The lower lip is thickened and has a shallow central groove. The ears are rather square­shaped with a straight anterior edge and a shallow notch on the distal third of the posterior margin, below the tip, giving it a pointed appearance. The ears of N. jamaicensis show rudimentary folds varying in number from five to seven.

The skull is relatively narrow and delicate. The braincase is greatly inflated and abruptly elevated above the rostrum in an angle great­ er than 608. The postparietal region is relatively wide in dorsal view, and is separated from the occipital region by a conspicuous ridge. The sagittal crest is greatly developed and, in the interparietal region, it is noticeably higher than in the supraoccipital region. The postorbital region is very narrow with nearly parallel sides. The rostrum is markedly flattened dorsoventrally, so that the orbits appear relatively narrow in lateral view. The sulcus between the nasal bones is short and shallow, being restricted to the posterior end of the rostrum. The premaxillary region does not project anteriorly, so that in lateral view the diastema between canines and incisors is not particularly noticeable. The maxillary bone is concave above the molars. The rostrum tips downward. The anterior palatal foramina are very small, and near the palatine emargination, their anterior edges lie posterior to the anterior edge of the canines. The bony palate extends more than half the distance between the posterior edge of last molars and the tip of pteryogids. The pterygoid processes are not markedly convergent, and are conspicuously hooked in lateral view. In ventral view the inner edge of each pterygoid is smooth and convex. The basisphenoid pits are very shallow, in contrast with the basisphenoid furrows, which are relatively deep.

The dentary bone is markedly curved (upturned) and thick. The angular process is relatively short, rather straight, and with a blunt spatulate end. The coronoid process is at about the same height as the condyle above the alveolar plane. The ascending ramus is markedly upturned, being relatively tall and square­shaped, with its anterior border concave at the base and rather straight for most of its length, rising from the alveolar plane in an angle close to 908. The posterior border of the ascending ramus rises from the base of the angular process in a nearly straight angle with the base of the dentary. The mental foramen is between the canine and the first premolar.

The upper incisors are small and with slightly hooked tips. The inner incisors are transversally aligned with the outer ones, so that the inner incisors are not visible in lateral view. The base of the canine is robust in occlusal view, with a well­developed cingulum that is slightly longer than it is wide. In occlusal view, the premolars are successively larger, and are relatively short and crowded. The molar row is relatively thick, its width about half the width of the palate. The first and second molar are approximately equal in size, with the third slightly smaller.

The lower incisors are small, tricuspid, and subequal. The canine is curved, relatively short, and with a well­developed cingulum. In occlusal view, the canine and the premolars are relatively short longitudinally, with the first premolar slightly shorter than the canine and the other two premolars. The first two molars are larger and wider than the third, the first more projected labially than the other two. The last premolar and the first molar are relatively crowded (fig. 3).

COMPARISONS: The large body size (forearm length 44.0–47.0 mm) of Natalus jamaicensis readily separates this species from Natalus stramineus (35.0–41.0 mm; Tejedor et. al., 2004) and Natalus tumidirostris (37.2–41.5 mm; Tejedor, unpublished data). From Natalus primus and Natalus major , N. jamaicensis is best distinguished by discrete external and/or cranial characters because, although clearly distinct in morphometry from the former two species (as shown by our principal component analysis [PCA] results; fig. 7), N. jamaicensis overlaps in size with the other two Greater Antillean species.

Natalus jamaicensis differs externally from Natalus primus by its pointed ear tips (rounded in N. primus ), and from Natalus stramineus and Natalus tumidirostris by its straight anterior ear margin (slightly to deeply concave in the latter two species). From Natalus major and all remaining species of the genus, N. jamaicensis is best distinguished on the basis of cranial characters. Most conspicuously, N. jamaicensis shows several cranial modifications concomitant with its high degree of cranial flexion. First, in N. jamaicensis the frontal plane of the braincase rises very steeply from the rostrum, in an angle greater than 608, a condition that is unique among species of the genus Natalus . Second, the braincase of N. jamaicensis is markedly inflated and almost as wide as it is long, hence it has an almost circular profile in dorsal view. In all other species of Natalus the braincase is longer than wider and thus appears oval­shaped. Third, the postorbital constriction of the skull of N. jamaicensis is proportionally narrower than in all other species of Natalus (mean postorbital breadth is significantly smaller than in N. major and N. primus ; P, 0.001; fig. 6), with sides almost parallel in dorsal view, whereas in all other species of Natalus the sides of the postorbital constriction markedly diverge anteriorly. Also, the rostrum of N. jamaicensis is flattened dorsally to a greater degree than in other species of Natalus , and shows a marked reduction of the sulcus between nasal bones, a rather dorsal location of the infraorbital foramen, and a concave shape of the maxillary in the area dorsal to the molars. The concave maxillary bone is sufficient to diagnose N. jamaicensis because all other species of Natalus have markedly convex to markedly inflated maxillary bones.

REMARKS: Fossil mandibles of Natalus from Grand Cayman were described by Morgan (1994) as being smaller than any other Greater Antillean Natalus , and as having a relatively large last premolar. Morgan referred to these fossils as Natalus cf. N. major and remarked that they may represent and undescribed form. Given the geographical proximity of the Cayman Islands to Jamaica and Cuba, it is probable that either of the populations of these two larger islands may be the closest relative of the Grand Cayman Natalus . Future examination of these fossils should shed light on this question.

Natalus jamaicensis

JAMAICA

St. Catherine Parish

1. St. Clair Cave, Linstead (188079N, 778019W). AMNH 181999 , 182000 (holotype), 214131, 246123, 246126–246128, 271575, 271576 (8 males, 1 female) ; FLMNH 13688–13692 (3 males, 2 females) ; FMNH 93784 (female) ; BMNH 65.4000 a, 65.4000b; JI No. 3, JI No. 4, Goodwin (1959) ; ROM 37029, 37065–37076 (4 females) .

St. Elizabeth Parish

2. Wallingford Cave, Balaclava (188109N, 778 399W). AMNH 147208 (fossil), Koopman and Williams (1951).

Figures

Fig. 2. Dorsal and ventral views of the skull of three species of Greater Antillean Natalus. A, Natalus primus (MNHN 51, field number); B, Natalus major (AMNH AT 51, field number); C, Natalus jamaicensis (AMNH 246127).

Fig. 3. Dorsal view of the right mandibular ramus of three species of Greater Antillean Natalus. A, Natalus primus, B, Natalus major, C, Natalus jamaicensis.

Fig. 4. Photograph of an adult male Natalus major (showing a bright yellowish pelage) captured in Cueva Grande de Julián, Sánchez Ramírez province, Dominican Republic, in January 2002. Photograph by A. Tejedor.