A new species of earth snake (Dipsadidae, Geophis) from Mexico

Abstract A new species of the Geophis dubius group is described from the mountains of the Sierra Zongolica in west-central Veracruz and the Sierra de Quimixtlán in central-east Puebla. The new species is most similar to Geophis duellmani and Geophis turbidus, which are endemic to the mountains of northern Oaxaca and the Sierra Madre Oriental of Puebla and Hidalgo, respectively. However, the new species differs from Geophis duellmani by the presence of postocular and supraocular scales and from Geophis turbidus by having a bicolor dorsum. With the description of the new species, the species number in the genus increases to 50 and to 12 in the Geophis dubius group. Additionally, a key to the species of the Geophis dubius group is provided.

. Distribution of the species of the Geophis dubius group. Bold lines represent country limits and narrow lines limits of Mexican states.

Materials and methods
The sample of the new species (n = 8) was compared with specimens of all of the species of the Geophis dubius group from Mexico, with the exception of G. rostralis. A list of the specimens examined is provided in Supplementary file 1: Table 1. Acronyms for herpetological collections follow Sabaj Pérez (2014), with the addition of ITSZ (Instituto Tecnológico Superior de Zongolica). SMR is an abbreviation for field numbers of uncatalogued specimens in the MZFC.
Scale nomenclature follows Downs (1967) and Savage and Watling (2008). Scale counts were performed with the aid of a dissecting microscope. Ventrals were counted as suggested by Downs (1967). Bilateral characters were scored on both sides. When the condition of a given character was not identical on both sides, the conditions on the left and right sides are given, in that order, separated by a slash (/). Measurements were taken with a ruler, digital calipers, or an ocular micrometer to the nearest 0.1 mm. Head length was measured from the tip of the snout to the posterior end of the parietals. All scale dimensions were measured at their maximum. To examine dentition characters, the maxilla and ectopterygoid were removed from the skull and cleansed in a dilute solution of Proteinase K for approximately one hour. Color codes and descriptions follow Smithe (1975). The diagnosis is based on both the specimens examined and the relevant literature (Bogert and Porter 1966, Downs 1967, Smith and Holland 1969, Campbell and Murphy 1977, Savage 1981, Campbell et al. 1983, Restrepo and Wright 1987, Smith and Chiszar 1992, Smith and Flores-Villela 1993, Lips and Savage 1994, Smith 1995, Wilson et al. 1998, Pérez-Higareda et al. 2001, Myers 2003, Nieto-Montes de Oca 2003, Savage and Watling 2008, Townsend 2009, Townsend and Wilson 2006, Pavón-Vázquez et al. 2011, 2013. Paratypes. Seven specimens, six from the Sierra de Zongolica of west-central Veracruz and one from the Sierra de Quimixtlán of adjacent Puebla, Mexico. Veracruz: Three from the same locality as the holotype (MZFC 28402-03, ITSZ 217); one from Zongolica, 18°39'02"N, 97°00'29"W, 1210 m (ITSZ 071); one from 7 km E Zongolica (MZFC 28405); one from Los Reyes, 18°41'48"N, 97°03'21"W, 1700 m (ITSZ 025). Puebla: Chichiquila, 19°11'35"N, 97°03'57"W, 1700 m (MZFC 28404).

Geophis lorancai
Diagnosis. A member of the Geophis dubius group characterized by the following combination of traits: eye relatively small (see below); single supraocular and postocular present on each side; fifth supralabial and parietal in contact; mental scale and anterior chinshields in contact; smooth dorsal scales throughout the body arranged in 17 rows; ventrals 130, n = 1, in females, and 125-130, n = 7, in males; subcaudals in males 33-35, n = 5; dorsal body and tail pattern consisting of dark crossbands on a paler, red-orange background; reddish orange venter; maxillary teeth 7.
Geophis lorancai may be distinguished from all of the species in the championi and semidoliatus groups, and all of the species in the sieboldi group except G. dunni, G. nasalis, G. occabus, and G. sieboldi by having the dorsal scales arranged in 17 rows (versus dorsal scales arranged in 15 rows in the other species); and from the latter four species by having smooth dorsal scales throughout the body (versus dorsal scales keeled on at least the posterior half of the body in the other species).
Geophis lorancai differs from all of the species in the omiltemanus and chalybeus groups by having a small eye (i.e., its horizontal diameter contained nearly four times in the snout length, versus its horizontal diameter contained less than three times in the snout length in the other species); in addition, it may be distinguished from all of the species in the omiltemanus group by having the fifth supralabial and parietal in contact (versus fifth supralabial and parietal separated by one anterior temporal in the other species); from some species in the chalybeus group (G. dugesii, G. nigrocinctus, and  Geophis lorancai may be distinguished from the species in the latifrontalis group as follows: from G. blanchardi and G. mutitorques, by having a dorsal body pattern consisting of dark crossbands on a paler, red-orange background (versus dorsum uniformly dark in G. blanchardi and adults of G. mutitorques-juveniles with yellow collar); from G. latifrontalis and G. mutitorques, by having the fifth supralabial and parietal in contact (versus fifth supralabial and parietal separated by one anterior temporal in G. latifrontalis and G. mutitorques); and from G. blanchardi and G. latifrontalis, by having the mental and anterior chinshields in contact (versus mental and anterior chinshields separated by the first pair of infralabials in G. blanchardi and G. latifrontalis).
Description of holotype (Fig. 2). Adult male. Head length = 8.9 mm, snout-vent length (SVL) = 268 mm, tail length = 53.4 mm. Head slightly distinct from body. Snout long, contained 2.2 times in head, rounded from above, projecting anteriorly far beyond lower jaw; rostral 0.7 times as broad as high, portion visible from above 0.3 times as long as its distance from frontal, 1.2 times as long as internasals common suture, with posterior end approximately at level of anterior margin of nostrils; internasals broader than long (length / breadth= 0.7/0.8), slightly angulate anteriorly, in lateral contact with anterior and posterior nasals, their length and common suture 0.7/0.8 and 0.5 times as long as prefrontals common suture, respectively. Prefrontals in lateral contact with postnasal, loreal, and eye on each side, and additionally with third supralabial on left side; their length 0.6 times snout length; their common suture 0.5 times frontal length. Frontal slightly broader than long (breadth / length ratio = 1.1). Supraocular large, in contact with prefrontal, frontal, parietal, and postocular; approximately 0.9 times as long as horizontal diameter of eye, 0.6 times as long as loreal, bordering posterior half of dorsal margin of orbit, ventral margin slightly projecting posteriorly beyond posterior margin of orbit. Parietals 1.5/1.6 times as long as broad, their length 0.5 times head length, their common suture 0.8 times as long as frontal.
Nasal divided. Postnasal 1.3/1.1 times as long as prenasal. Combined length of prenasal and postnasal subequal to loreal length. Loreal 1.4/1.5 times as long as deep, contained 2.7/2.5 times in snout length, 1.6 times as long as horizontal diameter of eye, its dorsal margin slightly concave; failing to reach orbit on the left side, in broad contact with anterior margin of orbit on right side. Eye small, contained 4.3 times in snout length, its vertical diameter 0.7 times its distance from lip. One postocular, 1.4/1.3 times as high as long, 1/0.8 times as long as supraocular. Supralabials 6/6, first and second in contact with postnasal, second and third in contact with loreal, third and fourth entering orbit (third contacting prefrontal on left side), fifth largest, in contact with parietal. Ventral margin of third supralabial 1.2/1.6 times that of second supralabial; ventral margin of fifth supralabial 1.9 times that of fourth supralabial, 1.0/1.1 times that of sixth supralabial. Anterior temporal absent. One posterior temporal. Five nuchal scales in contact with parietals.
Mental 1.2 times as broad as long, pointed anteriorly, in posterior contact with anterior chinshields. Infralabials 6/6, first to third in contact with anterior chinshields, third and fourth in contact with posterior chinshields. Anterior chinshields 1.6/1.7 times as long as broad, 1.4 times as long as posterior chinshields. Posterior chinshields in narrow contact with each other anteriorly, separated posteriorly by one midgular scale. Four midgular scales. Infralabials and scales in chin region smooth. Dorsals in 17-17-17 rows, smooth throughout the body; no evident apical pits. Ventrals 128. Subcloacal scute single. Paired subcaudals 34.
Color in life (Fig. 3): Dorsal and lateral surfaces of head and anterior end of body (to approximately level of 12 th middorsal scale) black; those of rest of body and tail with black transverse marks on a reddish orange background color (color 17, Spectrum orange; Smithe, 1975). Fifteen black transverse marks on body; 1 st -2 nd , 4 th -5 th , 7 th , 9 th , 11 th -12 th , and 14 th -15 th saddle-shaped, about 6-10 scales in length, usually extending laterally to lateral margin of ventral scales (one saddle extending laterally to third dorsal row on right side); remaining five marks consisting each of a transverse band extending on one side of body and bifurcating at midline into two transverse bands on opposite side, forming a Y-shaped mark; Y-shaped marks 7-9 scales in length at their longest. Reddish orange rings between saddles 4-6 scales in length. Eight black transverse marks on tail; anterior three saddle-shaped, about 1.5-4 scales in length, extending laterally to lateral margin of subcaudals or nearly so; 4 th mark irregular, elongate, presumably formed by fusion of several adjacent transverse marks, 9.5 scales in length at its longest, in lateral contact with first dorsal scale row at three points on each side; remaining marks shorter, irregular; posterior end of tail with black and red checkered pattern. Reddish orange rings between black marks 1-2.5 scales in length. Ventral surface of head pale grey; that of body and tail immaculate reddish orange except for one dark splotch on middle of 7 th ventral and black lateral ends of those ventrals involved in transverse body marks; tail surface increasingly dark posteriorly.
Dentition. The description below is based on the dentition on the right side of paratypes ITSZ 25 and MZFC 28402 and on the left side of paratype MZFC 28403. Scored characters were consistent in all the specimens. Maxilla extending anteriorly to level of suture between 2 nd and 3 rd supralabials; posterior fourth of maxilla curved ventrally in lateral view; anterior tip of maxilla toothless, bluntly pointed; maxillary teeth 7, recurved; teeth slightly longer at middle of maxilla; large flange projecting medially at approximately level of middle of maxilla; posterior end of maxilla laterally compressed into moderate flange. Anterior end of ectopterygoid bifurcate; dorsal branch long, compressed; ventral branch very short, stump-like.
Variation. This section is based on the examination of the seven paratypes. We describe only character conditions that differ from those in the holotype. Ranges are given for some characters. When ranges included the holotype, we report its condition. Two males (MZFC 28403-28404) have an incomplete tail; thus, subcaudal and total segmental counts, tail length, tail length / total length ratio, and number of tail black markings are not reported for those specimens.
Color pattern (Fig. 3). General pattern similar to that of holotype in all specimens. Transverse dark marks on body and tail 13-20 and 4-10, respectively. Body pattern composed of dark crossbands and Y-shaped marks in all specimens (10 and 2, in ITSZ 25;13 and 4, in ITSZ 71;17 and 3, in ITSZ 217;12 and 4, in MZFC 28402;12 and 2, in MZFC 28403;18 and 1, in MZFC 28404;15 and 2, in MZFC 28405) and single, unusual marks in some specimens: adjacent transverse bands connected to each other, forming a zigzagging mark, in two specimens (zigzagging mark in contact with lateral edge of ventral scales at three points on each side in ITSZ 25, at four points on one side and three points on opposite side in ITSZ 71); two adjacent transverse bands connected along midline, forming a H-shaped mark, in one specimen (MZFC 28404). Tail pattern composed of black crossbands in all specimens (7, in ITSZ 25;8, in ITSZ 71;2, in ITSZ 217;7, in MZFC 28402;5, in MZFC 28405) in addition to one Y-shaped mark in ITSZ 71, and one zigzagging mark in contact with lateral edge of ventral scales at two points on one side and three points on opposite side in ITSZ 217; posterior end of tail light in ITSZ 25, dark in MZFC 28402 and MZFC 28405, and checkered with red and black in ITSZ 71 and ITSZ 217. Ventral surface of head and body immaculate, except for black stippling, heavier on anterior portion of body, in ITSZ 71, and dark first ventral, lateral ends of ventrals gradually paler posteriorly, in two specimens (MZFC 28402-28403); ventral surface of tail paler, subcaudals adjacent to black dorsal marks with dark lateral ends; dark pigment gradually heavier pos-teriorly; dark pigment on posterior edge of most subcaudals in two specimens (MZFC 28402 and 28404).
Etymology. The specific name is treated as a noun in the genitive case and honors Biologist Miguel Ángel de la Torre Loranca, who obtained most of the specimens of the new species from the Sierra de Zongolica.
Distribution and ecology (Fig. 1). Geophis lorancai is known from the Sierra de Zongolica of west-central Veracruz and the Sierra de Quimixtlán in adjacent extreme east-central Puebla between 1210 and 1700 m elevation (Fig. 1). All of the specimens of G. lorancai were obtained between October 1996 and April 2013. In these sierras, the terrain is irregular with numerous hills (some of them isolated), ascents and descents, and streams. The terrain shows a general decline towards the Gulf coastal plain (i.e., from west to east). The area is covered with cloud forest and pine-oak associations. In both sierras, G. lorancai is sympatric with G. semidoliatus, another species with dark crossbands on a red background belonging to the G. semidoliatus group.
All of the specimens of Geophis lorancai were found in cloud forest. The principal arboreal components of the vegetation at the type locality are Liquidambar styraciflua, Quercus spp., Saurauia scabrida, Clethra mexicana, Lippia myriocephala, Heliocarpus appendiculatus, Magnolia mexicana, Carpinus carolineana, and Ternstroemia sylvativa. The bush stratum is dominated by Psychotria galeottiana, Piper ssp., Phyllonoma laticuspis, and Miconia spp. Species found in the herbaceous stratum are Smilax spp., Selaginella spp., Begonia spp., Monstera deliciosa, Philodendron spp., Salvia spp., and Dhalia coccinea. Epiphytes of the Bromeliaceae and Orchidaceae families are common in this type of vegetation and mainly represented by the following species: Tillandsia punctulata, T. multicaulis, Nidema boothii, Lycaste deppei, and L. consobrina (Rzedowski 1978, Cázares Hernández personal communication). The specimens of G. lorancai were found either among the leaf litter or under fallen logs.

Discussion
With the addition of Geophis lorancai, the number of species in the genus increases to 50, and the number of species in the G. dubius group to 12, of which ten occur in Mexico (Fig. 1): seven are endemic to Mexico (G anocularis, G. dubius, G. duellmani, G. juarezi, G. lorancai, G. rostralis, and G. turbidus), two are shared only with Guatemala (G. carinosus and G. immaculatus), and one with Guatemala, El Salvador, and Honduras (G. rhodogaster). Two species are distributed only in Central America: G. nephodrymus in Honduras and G. fulvoguttatus in Honduras and El Salvador.
Geophis lorancai fills a gap in the distribution of the G. dubius group between the ranges of G. turbidus and those of the species from northern Oaxaca. Pavón-Vázquez et al. (2013) described G. turbidus from northern Puebla. This species has been recently reported also from adjacent Hidalgo (Cruz-Elizalde et al. 2015), and represents the northern limit of the distribution of the G. dubius group. With the exception of a doubtful record of G. dubius from "Jalapa" in central Veracruz (see below), the closest records to G. lorancai of this group are found in northern Oaxaca, where several endemic species are found (i.e., G. anocularis, G. duellmani, and G. juarezi). Other species found in Oaxaca are G. dubius, widely distributed in central and northern Oaxaca, and G. rostralis, from the Sierra Madre del Sur.
The validity of the record from Jalapa has been questioned. Bogert and Porter (1966) considered this record as doubtful on the basis that although "Jalapa" was the locality given by Fischer (1886) as the source of the specimen he described as G. fuscus, he did not specify the state and there are ''at least a dozen'' other localities with the same name in Mexico, including two in the state of Oaxaca. For many years central Veracruz has been a collecting site for many herpetologists, yet G. dubius has never been found there. The only species of Geophis found in central Veracruz are the common G. semidoliatus (semidoliatus group), G. blanchardi, G. mutitorques (both belonging to the latifrontalis group), and G. chalybeus (chalybeus group). According to this, and the fact that G. dubius is a common species in the state of Oaxaca, it seems possible that the specimen from Jalapa assigned to this species comes from Oaxaca.
Geophis lorancai and G. turbidus are similar in scalation and relatively close geographically. Thus, it is conceivable that these two taxa represent the same species with two color morphs: one predominantly dark and another one with dark crossbands on a red-orange background, as in the polymorphic species G. occabus and G. brachycephalus (Pavón-Vázquez et al. 2011). However, a phylogenetic analysis of Geophis based on several mitochondrial and nuclear genes shows that G. lorancai and G. turbidus are considerably divergent genetically and not each other's sister species (Canseco-Márquez et al. unpublished data).