Nephelomys ricardopalmai, Ruelas & Pacheco & Inche & Tinoco, 2021

Ruelas, Dennisse, Pacheco, Víctor, Inche, Betsy & Tinoco, Nicolas, 2021, A preliminary review of Nephelomys albigularis (Tomes, 1860) (Rodentia: Cricetidae), with the description of a new species from the Peruvian montane forests, Zootaxa 5027 (2), pp. 175-210 : 192-196

publication ID	https://doi.org/ 10.11646/zootaxa.5027.2.3
publication LSID	lsid:zoobank.org:pub:96F3122D-88C9-4246-8A2D-4FFD3C3F4065
persistent identifier	https://treatment.plazi.org/id/03AB6665-FFCE-5154-F0F3-FDEEFD13FDD3
treatment provided by	Plazi
scientific name	Nephelomys ricardopalmai
status	sp. nov.

Treatment

Nephelomys ricardopalmai , new species

Ricardo Palma’s rice rat

Figs. 8 View FIGURE 8 , 9 View FIGURE 9 , and 10

Hesperomys (Calomys) albigularis: Thomas, 1882:103

Oryzomys albigularis: Thomas, 1926:160 View in CoL

Nephelomys albigularis: Uturunco and Pacheco, 2016:503 View in CoL

Holotype. An adult female preserved as dry skin, skull, and body carcass in alcohol, deposited at Museo de Historia Natural , Universidad Nacional Mayor de San Marcos, Lima, Peru (MUSM 46989); collected by Víctor Pacheco (original number VPT 4500) on May 08, 2016.

Paratypes. Ten adult specimens collected in the Área de Conservación Privada Huiquilla, from 2781 m to 3056 m elevation: four adult females preserved as fluid with the removed skull (MUSM 46995, 46991, 47016, 47020), five adult males preserved as fluid with the removed skull (MUSM 46990, 47015, 47005, 47019, 47021), and one adult male preserved as skin, removed skull, and body carcass in alcohol (MUSM 46994). Measurements of the type series are presented in Table 6 .

Type locality. Área de Conservación Privada Huiquilla (6° 23’ 04” S, 77° 59’ 18” W, 2781 m a.s.l.), Longuita District , Luya Province, Amazonas Department, Peru ( Fig. 11 View FIGURE 11 ) GoogleMaps .

Distribution. Nephelomys ricardopalmai is found in the montane cloud forest of Amazonas and San Martín Departments, between the right margin of the Marañón River and the left margin of the Huallaga River ( Fig. 1 View FIGURE 1 ).

Etymology. The specific name is given in honor of the Peruvian politician, journalist, and writer Ricardo Palma Soriano (1833–1919). Among his main achievements, Ricardo Palma is recognized for the foundation of the Academia Peruana de la Lengua , for his traditional writing about the Peruvian customs represented in his well-known “Tradiciones Peruanas”, and for the reconstruction of the National Library after the War of the Pacific (1879–1883) as part of the post-war national reconstruction, for which he was named as “El Bibliotecario mendigo” (“The beggar Librarian”). In this war, the original manuscript of his novel “Los Marañones” was burned ( Pantigoso Pecero 2018), which was said to narrate the Spanish explorer’s adventures and rebel conquistador Lope de Aguirre in the Peruvian Amazonian.

Diagnosis. This montane rat of the genus Nephelomys is differentiated from their congeners by the following combination of morphological traits: slightly long hairs at rump level (~ 11.3 mm); whitish tips of the ventral pelage; short and scattered hairs on the lateral margin of the metatarsal; short silver hairs on the metatarsal; narrow hypothenar pads; faintly bicolor tail; white pectoral patch; slightly narrow rostrum; narrow and hourglass-shaped interorbital region; interorbital ridges absent; convergent and narrow zygomatic arches; low zygomatic plates; short and usually narrow incisive foramina; posterior margin of the hard palate smoothly squared or with a small median postpalatal process; simple and small posterolateral palatal pits that sit in a shallow fossa; ventral margin of the external auditory meatus with a smooth edge and no cleavage; slightly large toothrow; slightly broad M1; narrow and long anteroloph of M1; deep metaflexus of M1; deep hypoflexus of M2; deep posteroflexid of m2; developed anterolabial cingulum of m2; deep protoflexid of m3; slightly angular mandibular sigmoid notches; and thin coronoid processes.

Morphological description. Figs. 4–6 View FIGURE 4 View FIGURE 5 View FIGURE 6 , 8–10. A View FIGURE 8 View FIGURE 9 View FIGURE 10 medium-sized oryzomyine rodent (Total length: 289.00— 323.00 mm). Body. The tail is conspicuously longer than head and body length (about 114 %) and faintly bicolor. In the manus, digit I is small compared with the other digits, and digit V is smaller than digit II. In the pes, digit I is smaller than digit V (dV), and this last is smaller than digit II. Scales on the hindfoot are small and a narrow hypothenar pad is present on the plantar surface. Pelage. The dorsal pelage is slightly long (11.3 mm on average on the rump), soft, and bicolored, with the base “Blackish neutral gray” color (color 82) and the tips “Clay color” (color 26). The tips of the lateral pelage are “Cinnamon” (color 39), and the tips of the ventral pelage are whitish. No sharp delimitation is observed between the dorsal, lateral, or ventral pelage. A white pectoral patch is always present, in which hairs are completely white. The metatarsals are covered with short and silver hairs, and the hairs are short and scattered on the lateral margin. The genal vibrissae extend backward beyond the pinnae. Two or three short carpal vibrissae reach the base of dV. Skull. The braincase is slightly inflated. The rostrum is slightly narrow. The nasal bones have an anterior border rounded and a posterior margin slightly rounded. The nasal bones are short, not extending to the level of the lacrimal bones. The lacrimal bones are small and slightly square. The interorbital region is narrow and hourglass-shaped, without interorbital ridges. The zygomatic arches are convergent and narrow. The zygomatic notches are deep. The zygomatic plates are placed low and have a rounded anterior border. The incisive foramina are short, not reaching the anterior border of the M1, narrower than the breadth of the palate, and have a parenthesis-shape. The premaxillary portion of the incisive foramina septum is broad. The carotid circulation pattern is type 1 (sensu Voss 1988). The palate is long. The posterior margin of the hard palate (the anterior limit of the mesopterygoid fossa) is smoothly squared or with a small median postpalatal process present (64.44 %, 35.56 %, respectively). The posterolateral palatal pits are small, simple, and sit on a shallow fossa. The auditory bullae are slightly swollen. The Eustachian tubes are medium size and slightly broad. The ventral margin of the external auditory meatus has a smooth edge without a cleavage. The alisphenoid struts are usually absent (82.35 %). The tegmen tympani is reduced and does not overlap the squamosal bone. The hamular processes of pterygoid bone are broad and short. Mandible. A capsular process is present but does not reach the sigmoid notch. The sigmoid notch is slightly deep and angular. The coronoid processes are short, thin, and pointed; and the angular processes are broad.

Teeth. Upper incisors are opisthodont with enamel pigmented yellow or pale yellow. The toothrows are slightly large (5.25—5.89 mm). The upper molar rows are parallel. The protocone, paracone, hypocone, and metacone are well-defined cusps in the M1 and M2 and less defined in the M3. The M1 presents a procingulum asymmetrically divided into anterolingual and anterolabial conules by a deep anteromedian flexus; the anterolabial conule is larger than the anterolingual conule; the anteroloph and mesoloph are well developed, anteroloph is narrow and long; the paraflexus, metaflexus, protoflexus, and hypoflexus are deep; the mesoflexus is slightly deep. The M2 presents well developed anteroloph and mesoloph; the posteroloph is little developed; the paraflexus and metaflexus are very deep, but the mesoflexus and hypoflexus are not very deep. The M3 presents well developed anteroloph and mesoloph; the paraflexus, mesoflexus, metaflexus, and hypoflexus are conspicuous. The first (m1) and second (m2) lower molars have protoconid, paraconid, hypoconid, metaconid, and entoconid well-defined; the mesolophid is present, well developed, and projected lingually; the hypoflexid is deep, and the posterolophid is well developed. The m1 exhibits an anteromedian flexid that asymmetrically divides the procingulum into anterolingual and anterolabial conulids; the anterolophid and protolophid are present; the anteroflexid, metaflexid, and protoflexid are deep; the posteroflexid of m2 is deep. In the m3, the metaconid, protoconid, and hypoconid are well defined, and the entoconid is very small; the anterolabial cingulum is developed and narrow, and the protoflexid is deep.

Morphological comparisons. Comparisons among species of Nephelomys from the Peruvian Yungas are detailed in the morphological qualitative evidence results (see above) and summarized in Table 4 and Figs. 4 View FIGURE 4 , 5 View FIGURE 5 , and 6.

Habitat. Nephelomys ricardopalmai sp. nov. occurs in the montane cloud forests, or Peruvian Yungas, from 1900 m to 3200 m elevation. Following Britto (2017), N. ricardopalmai inhabits Montane Rain Forest and Very Humid Montane Forest. The Private Protected Area Hierba Buena—Allpayacu and Copal, located in the Corosha district, Amazonas, is characterized by being permanently cloudy; nonetheless, a wet season and a dry season are well marked, with an elevational range from 1800 to 3040 m ( Chávez Argandoña 2018). The Corosha cloud forest consists of low (10 to 15 m high) canopy forests, with trees covered by bromeliads, orchids, mosses, and lichens. The Rio Abiseo National Park in the San Martín Department includes misty forest at 3200 m elevation, low tree forest on sandy terraces at 2650 m elevation, riparian vegetation of a sandy beach at 2100 m elevation, and forest of tall trees and undergrowth between 2000 and 2100 m elevation ( Leo & Romo 1992).

breviations are described in Material and methods.