Enchisthenes hartii (Thomas, 1892), in Jalisco, Mexico, 68 and 47 years after its first and last record

The velvety fruit-eating bat, Enchisthenes hartii (Thomas 1892), is a fruit bat species belonging to the monotypic genus Enchisthenes of the family Phyllostomidae (Andersen 1906; Arroyo-Cabrales 2005; Arroyo-Cabrales and Owen 1996). E. hartii has a dark, almost blackish fur coloration on the head and shoulders, which allows it to be distinguished from other members of the Stenodermatinae subfamily (Arroyo-Cabrales 2005; Goodwin 1940). This species has a wide distribution from north-central Mexico to southern Bolivia (Solari 2019), and has been collected mainly in montane cloud forest and pine-oak forest, between 1300 and 2200 m a.s.l (Arroyo-Cabrales and Owen 1997).

In Mexico, E. hartii is distributed in the highlands of the coastal slopes, from Jalisco in the west and Tamaulipas in the northeast and south to Chiapas (Orozco-Lugo et al. 2008). Historically, this species is considered rare or uncommon in Mexico, since records have been occasional and very scarce. However, there are records in scientific literature (Arroyo-Cabrales and Owen 1996; Cervantes et al. 2004; Orozco-Lugo et al. 2008), and institutional databases: National Information System on Biodiversity of Mexico (SNIB, https://www.snib.mx/); Field Museum of Natural History (https://collections-zoology.fieldmuseum.org/taxonomy/311756); The Museum of Natural History, and University of Kansas (https://biodiversity.ku.edu), that provide information on the distribution of E. hartii in Mexico.

So, E. hartii has been collected and recorded initially in ten states (Arroyo-Cabrales and Owen 1996). Recently, its distribution area expanded in two more states, Hidalgo and Morelos, where it was recorded for the first time in 2004 and 2008, respectively (Cervantes et al. 2004; Orozco-Lugo et al. 2008). In total, there are 95 records of E. hartii in Mexico; 70% of the collections originate from Chiapas and Oaxaca (56 and 11 specimens, respectively), while there is only a record of four collected specimens in 1954, three in 1964, and one in 1975 in Jalisco (https://www.snib.mx/; https://collections-zoology.fieldmuseum.org/taxonomy/311,756; https://biodiversity.ku.edu). The objective of this note is to report the presence of E. hartii in the southern coast region of the State of Jalisco in western Mexico, based on the capture of an individual in the municipality of Autlán de Navarro.

During a field trip carried out in January, 2022, bats were captured with four 12-m-long mist nets. Of the captured bats, at 9.00 p.m. one was a pregnant female E. hartii (Figure 1). Specifically, the specimen was captured in a tree corridor, near a stream, 0.1 km from an open cattle pasture used for grazing cows, approximately 2.4 km south of the Ejido de Ahuacapán. The site coordinates are 19°39′24.8´´ N and 104°19′8.2´´ W, with an altitude of 1101 m a.s.l. The climate in the study area is very warm semi-dry (Bs1), with an average annual temperature of 24.7 °C, and an average annual rainfall of 852 mm. The rainy season is in summer, with a marked dry season from November to May (Jardel 1992).

Figure 1:

First record for Enchisthenes hartii in the southern coastal region and Sierra de Manantlán in Jalisco, Mexico. Lateral view with the blackish fur coloration on the head and shoulders (photo: A. García-Méndez).

The landscape around the capture site is a mosaic of grazing cattle pastures, remnants of tropical deciduous forest, and gallery forest. The remnants of tropical deciduous forest are found on slopes and streams beds, and have trees that reach heights of 8–15 m, e.g., Lysiloma acapulcenses, Jacaratia mexicana, Ceiba aesculifolia, Bursera spp, Acacia macilenta, Guazuma ulmifolia (Jardel 1992). While the gallery forest forms a tree corridor of 1.12 km long and 0.07 km wide, along the Ahuacapán stream, and presents randomly distributed tree species, such as Ficus spp., Populus guzmanantlensis, Salix humboldtiana, Inga eriocarpa y Astianthus viminalis (pers. observ.).

The E. hartii individual was identified and released at the capture site. The identification was made using field guides and taxonomic keys (Medellín et al. 2008; Mónica-Díaz et al. 2021; Reid 1997). The specimen presented the following morphological characters: soft, short fur with a velvety appearance; dark brown on the back, darker below, almost blackish on head and shoulders; four narrow light brown lines were observed on the face; the caudal membrane was short and in the shape of an inverted V and presented hairs on the edge. External measurements (mm) were: total length, 55.7; hind leg length 11.2; ear length, 13.3; forearm length, 40.26; body mass 19.1 g. The measurements of this individual correspond to previously described specimens reported for other localities in Mexico (Arroyo-Cabrales and Owen 1996; Cervantes et al. 2004; Orozco-Lugo et al. 2008). Other bat species captured along with E. hartii were in order of abundance: Sturnira hondurensis, Desmodus rotundus, Sturnira parvidens, Dermanura tolteca, Artibeus jamaicensis and A. lituratus.

We conducted a systematic search of records of E. hartii for the State of Jalisco, specifically from protected natural areas (Sierra de Manantlán Biosphere Reserve, Chamela-Cuixmala Biosphere Reserve, Sierra de Quila flora and fauna protection area, and La Primavera flora and fauna protection area), including scientific papers (Iñiguez-Dávalos and Santana 1993, 2004) and databases of biological collections: Institute of Biology, National Autonomous University of Mexico (IBUNAM); National School of Biological Sciences (ENCB), in Mexico; and Field Museum of Natural History (FMNH) and The Museum of Natural History, University of Kansas (KU), in the United States, where specimens are deposited.

Our record of E. hartii is the first one after 68 and 47 years, when it was first and last collected in the State of Jalisco, respectively (Braun and King 2017; Vargas-Cuenca et al. 2014). This record is the first for the southern coastal region and Sierra de Manantlán in Jalisco. A previous record in Colima, near Hacienda San Antonio, was collected in 1976 (Feeney 2016), approximately 39.2 km southeast of our new record, at 1189 m a.s.l. Of the eight previous records of E. hartii for the State of Jalisco, only three were dated and located precisely: 1954 in the municipality of Zapotlán El Grande, near Ciudad Guzmán (Vargas-Cuenca et al. 2014); 1964 Mascota, near Talpa de Allende (Slade 2017); and 1975 in Tuxpan, near Atentique at 1600 m a.s.l (Braun and King 2017), ca. 91 km east, 84.2 northwest and 85.9 km east of the new record, respectively (Figure 2).

Figure 2:

Records of the presence of the E. hartii in Jalisco and Colima states: new record and historical records.

In Mexico, E. hartii is a rare species, since the collected specimens are isolated records, and information on its natural history and ecology is scarce, which limits the determination of the conservation status of this species. However, according to the Official Mexican Standard-NOM-059-SEMARNAT-2010, E. hartii is considered under special protection (Diario Oficial de la Federación 2010). Its reproductive cycle is poorly known. We report the capture of a pregnant female of E. hartii in January. Previously, in Mexico Álvarez and Álvarez-Castañeda (1991) reported a pregnant female captured in August, in Chiapas. Other authors describe captures of lactating females in April in Michoacán (Sánchez-Hernández et al. 1985), and in May, June and July in Chiapas (Baker et al. 1971). Then, it is possible that E. hartii can reproduce at different periods of the year, depending on the local availability of resources. In Costa Rica, E. hartii has been reported to breed throughout the year (Armstrong 1969; Gardner et al. 1970). It is necessary to establish systematic monitoring to generate more extensive knowledge about its distribution and conservation status in Mexico.