Phylloderma septentrionalis Goodwin 1940

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Phylloderma septentrionalis Goodwin, 1940 Phylloderma stenops septentrionalis – Handley (1966: 762) Examined material. 6 specimens including 6 skins, 6 skulls, 2 complete mitochondrial genomes. Holotype. AMNH 126868 (14°18.00’N; 87°50.00’W), an adult female, collected by Cecil F. Underwood (collector number 2033), skin with skull removed (Goodwin 1940), the specimen is housed in the American Museum of Natural History, New York, USA. Type locality. “ Las Pilas, six miles north of Marcala, about 4000 feet elevation; Department of La Paz, Honduras, March 26, 1937 ”. Diagnosis. Phylloderma septentrionalis is distinguished by its larger size (FA 65.4–82.5 mm; GLS 32.7–35.3 mm), pointed ears with subtle striations, and a high, rounded braincase. It differs from P. stenops by the presence of bilobed upper inner incisors, a non-pointed main cusp on the third lower premolar (p 4), and shallower upper molar cusps with reduced metastylar and parastylar shelves. The skull is robust, with a short rostrum and complete, rounded zygomatic arches. Externally, the underparts are distinctly paler and extend over the shoulders and neck sides, contrasting with the darker dorsal fur and wing membranes. Description. Phylloderma septentrionalis is a large and robust species. Reported measurements for this species, including the ranges from this study, are: Total length 109.6–137 mm, forearm length 65.4–82.5 mm; and greatest skull length 32.7–35.3 mm (Goodwin 1940, Bárquez and Ojeda 1979; Hall 1981). Externally, it is similar to P. stenops, but larger and differing in cranial characters (Goodwin 1940). The chin has a V-shaped naked cushion, margined by round papillae. The nose leaf is slender. The hair is short. The upperparts are brown with lighter bases; the underparts with the light coloration extending to the shoulders and the sides of the neck; the wing membranes are blackish brown (Goodwin 1940; Hall and Kelson 1959). The ears are large and pointed, with slight undulations on their posterior half; the tragus is long and narrow. The tail is visible from the upper side of the uropatagium. The upper inner incisors are bilobed; the upper external incisors are small, without evident lobulation, although the cutting edges are not uniform. The lower external incisors have irregular cutting edges but are not evidently bilobed and somewhat smaller than the internal ones. Goodwin (1940) noted that the inner lower incisors are twice as wide as the outer; however, they are not wider, but longer. The anterior face of the upper canine lacks longitudinal grooves. The lower canine has a cingulum on its inner side rising less above the level of the incisors when viewed from the front. The anterior upper premolar (P 1) is in contact with canine anteriorly and with the posterior upper premolar (P 3) posteriorly but not mounted on it. The second lower premolar (p 3) is tiny and is located between the other two premolars. The main cusp of the third lower premolar (p 4) lacks a point. The upper molars have shallow metacones and paracones and the metastylar and parastylar shelves are relatively shorter, with a distinct W-shaped pattern. The lower molars have trigonids with sharp and serrated cuspids (Goodwin 1940). The braincase is relatively high and rounded. The rostrum is shorter than the braincase, with no depression between the orbits. It is also rather wide, giving a robust appearance to the skull. The zygomatic arches are rounded and complete (Goodwin 1940) (Fig. 4). Comparisons. The averages of the craniodental and external measurements analyzed in this study were greater for P. septentrionalis than for P. stenops. In the cases of GLS, MET III, MET IV, and METV, the measurements do not overlap and are always greater in the northern Central American species. The skull differs in size, but not in shape, although there are some differences in the teeth worth noting: the upper inner incisors are bilobed in P. septentrionalis, but with smooth or weakly bifid cutting edges in P. stenops (Bárquez and Ojeda 1979); the main cusp of the lower third premolar (p 4) is not pointed in P. septentrionalis, but the contrary in P. stenops; the metacones and paracones are rather shallow, and the metastylar and parastylar shelves are shorter in P. septentrionalis compared to P. stenops. The ears of P. septentrionalis are pointed, with less visible striations, while in P. stenops they are rounded with more marked inner striations (Bárquez and Ojeda 1979) (Fig. 4). Distribution and habitat. Phylloderma septentrionalis occurs from southern Mexico (Oaxaca and Chiapas) to Nicaragua, presumably with the Hess Escarpment as the limit of its distribution (Fig. 5). This species is considered rare and inhabits primarily lowland and humid forest, although it has been recorded from a variety of forested and agricultural habitats (Carter et al. 1966; Timm et al. 1989; Santos-Moreno and Gallardo 2014). Natural history. This species consumes fruits, other plant materials, and insects (LaVal 1977; McCarthy 1982; York 2008). York (2008) suggested that it may be an effective seed disperser for some Annonaceae and Cucurbitaceae; however, details on the dietary breadth in the species remain unknown. Little is known about the reproductive cycle; LaVal (1977) reported capturing a pregnant female with a single embryo during the dry season (early February) in Costa Rica; this specimen also carried four males of the bat fly Strebla christinae. Remarks. Goodwin (1940) designated AMNH 126868 as the holotype of Phylloderma septentrionalis and mentioned additional paratypes from La Flor Archaga, Honduras, but did not provide catalogue numbers for them. Because paratype status could not be corroborated from the AMNH labels or database records available to us, no additional specimens are treated here as confirmed paratypes. The holotype was not included among the measured specimens; the comparative material from Las Pilas includes AMNH 126867 and AMNH 126869. Conservation status. The International Union for Conservation of Nature (IUCN) currently classifies Phylloderma stenops as ‘ Least Concern’, but P. septentrionalis has not been assessed separately. However, the Mesoamerican taxon (formerly Phylloderma s. septentrionalis) is listed as “ Threatened ” within the Conservation Initiatives for the Mammals of Oaxaca, Mexico (Briones-Salas et al. 2016), and is deemed “ Critically Endangered ” in Nicaragua (Medina-Fitoria 2014; Nassar et al. 2020). In Honduras, it has not been categorized under any risk or threat category (Turcios-Casco et al. 2020). Its conservation status remains unstudied in Guatemala, Belize, and El Salvador. Given its rarity in Central America and its restriction to well-preserved habitats, its vulnerability increases with threats to ecosystems. Recognition of P. septentrionalis at the species level may help prioritize conservation strategies for the species in Central America, particularly by encouraging studies of its distribution, abundance, and vulnerability.