Abronia zongolica, García-Vázquez & Clause & Gutiérrez-Rodríguez & Cazares-Hernández & Torre-Loranca, 2022

García-Vázquez, Uri Omar, Clause, Adam G., Gutiérrez-Rodríguez, Jorge, Cazares-Hernández, Erasmo & Torre-Loranca, Miguel Ángel de la, 2022, A New Species of Abronia (Squamata: Anguidae) from the Sierra de Zongolica of Veracruz, Mexico, Ichthyology & Herpetology 110 (1), pp. 33-49 : 36-44

Abronia zongolica , new species

urn:lsid:zoobank.org:act:0A5746B6-D2CE-4F46-AD2E-

19C9CD2E6D30

Sierra de Zongolica Arboreal Alligator Lizard

Dragoncito de la Sierra de Zongolica

Figures 2 , 3 , 4 ; Tables 1 , 2

Abronia graminea .— Guzmán Guzmán, 2011: 125 (in part).

Holotype.— MZFC-HE 35664 (field number LOR 251 ), adult male, Ayahuatulco, Municipality of Mixtla de Altamirano , Sierra de Zongolica, Veracruz, Mexico, 18.608N, 97.028W, datum WGS84, 1600 m elevation, J. R. Hernández Ginez, 20 December 2018.

Paratypes.— 6 specimens, all collected in the Sierra de Zongolica , Veracruz, Mexico. MZFC-HE 35663 , 1 subadult female, same collection data as the holotype; MZFC-HE 35665 , 1 adult male, MZFC-HE 35662 , 1 neonate, Teopantzacoalco , Municipality of San Juan Texhuacán, 18.608N, 97.058W, datum WGS84, 1785 m elevation, M. Á. de la Torre-Loranca, J. C. Sánchez-García, and U. O. García-Vázquez, 23 November 2018; MZFZ 4408 , 1 adult male, MZFZ 4406 , 1 adult female, MZFZ 4407 , 1 neonate, Atiopa , Municipality of San Juan Texhuacán, 18.618N, 97.048W, datum WGS84, 1670–1760 m elevation, M. Á. de la Torre-Loranca and J. R. Hernández Ginez , between October 2018 and February 2019 .

Referred specimens.— 5 vouchers, all from the Sierra de Zongolica, Veracruz, Mexico: MZFZ-IMG 309–311, Huapango, Municipality of Astacinga; MZFZ-IMG 312, Atiopa, Municipality of San Juan Texhuacán; MZFZ-IMG 313, Ayahuatulco, Municipality of Mixtla de Altamirano. All locality data in this and the preceding two paragraphs are masked; see the first paragraph of the Conservation subsection for details.

Diagnosis.— Abronia zongolica can be distinguished from all described congeners (including members of the former genus Mesaspis ) by the following combination of characters: (1) one occipital scale; (2) two primary temporal scales contacting the postocular series; (3) posterolateral head scales moderately protuberant; (4) supra-auricular scales granular, not protuberant or spine-like; (5) 30–34 transverse dorsal scale rows; (6) dorsal scales on the flanks arranged in slightly oblique longitudinal rows relative to the ventrolateral fold; (7) lateralmost row of ventral scales unexpanded relative to the adjacent medial row.

Comparisons.— ( Tables 1 , 2 ) Among members of the former genus Mesaspis , which was recently placed in the synonymy of Abronia based on genomic evidence ( Gutiérrez-Rodríguez et al., 2021), Abronia zongolica differs from all species by having dorsal scales on the flanks arranged in slightly oblique longitudinal rows relative to the ventrolateral fold (vs. parallel longitudinal rows), and by having 30–34 transverse dorsal scale rows (vs..40 rows). The new species further differs from A. cuchumatanus , A. gadovii , and the A. moreletii complex by having 14 longitudinal dorsal scale rows (vs. 16 or 18, 16–18, and 18–22, respectively); from A. antauges and A. juarezi by having vertebral and paravertebral dorsal scales distinctly keeled at midbody in adults (vs. smooth to slightly convex); from A. viridiflava by having the frontonasal scale present (vs. absent); and from A. monticola by having a divided postmental scale in 6/7 or 86% of specimens (vs. undivided).

Among members of Abronia not formerly attributed to the genus Mesaspis , Abronia zongolica differs from all species except the deppii group (sensu Campbell et al., 2016; contra Campbell and Frost, 1993) by having dorsal scales on the flanks arranged in at least slightly oblique longitudinal rows relative to the ventrolateral fold (vs. parallel longitudinal rows in other species), and differs from all species except the subgenera Abronia , Aenigmabronia , and Scopaeabronia (plus a few individuals of A. lythrochila ; see Campbell and Frost, 1993) by having the lateralmost row of ventral scales unexpanded relative to the adjacent medial row (vs. expanded in other species). The new species further differs from the subgenera recognized by Campbell and Frost (1993) as follows. Unlike the subgenus Abaculabronia , the new species has a dorsum with dark, sometimes interrupted or faint crossbands in living adults (vs. dorsum with no trace of crossbands in living adults), and the supranasal scales not in contact (vs. in contact in 8/9 or 89% of specimens). Unlike the subgenus Aenigmabronia , the new species has one occipital scale (vs. two occipitals), and protuberant head shields on the posterolateral ‘‘corners’’ of the head are present (vs. absent). Unlike the subgenus Auriculabronia , the new species has protuberant or spine-like supra-auricular scales absent (vs. present). Unlike the subgenus Lissabronia , the new species has protuberant head shields on the posterolateral ‘‘corners’’ of the head present (vs. absent). Unlike the subgenus Scopaeabronia , the new species has the lower primary temporal unexpanded (vs. expanded), six longitudinal nuchal scale rows (vs. eight rows), and 30–34 transverse dorsal scale rows (vs. 38–47 rows).

Additionally within the subgenus Abronia , the new species shares with the deppii group the morphological synapomorphy of having dorsal scales on the flanks arranged in at least slightly oblique longitudinal rows relative to the ventrolateral fold. Because both the deppii group and the subgenus Abronia , unlike all other subgenera mentioned in the previous paragraph, are non-monophyletic based on the genomic analysis of Gutiérrez-Rodríguez et al. (2021), we here compare the new species to each species within the subgenus Abronia . Among non- deppii -group members of this subgenus ( A. fuscolabialis , A. graminea , and A. taeniata ; Group III of Gutiérrez-Rodríguez et al., 2021), the new species differs by having an oblique row of enlarged lateral neck scales, each

3 times larger than adjacent scales (vs. row of enlarged scales absent, or poorly developed and not reaching nuchal scales); flanks at least partially yellow and contrasting with darker back in adult males (vs. flanks and back similar in color); and dorsal scales on the flanks arranged in slightly oblique longitudinal rows relative to the ventrolateral fold (vs. parallel longitudinal rows). Within the deppii group, the new species differs from A. deppii and A. martindelcampoi (Group I of Gutiérrez-Rodríguez et al., 2021) by having the anterior superciliary scale contacting the cantholoreal scale (vs. usually not in contact), the first postorbital supralabial scale not enlarged (vs. enlarged), two primary temporal scales contacting the postocular series (vs. one), and 30–34 transverse dorsal scale rows (vs. 27–29 in A. deppii and 24– 28 in A. martindelcampoi ). Within the oaxacae group nested within the deppii group ( A. cuetzpali , A. mixteca , and A. oaxacae ; Group V of Gutiérrez-Rodríguez et al., 2021), the new species differs by having one occipital scale (vs. two or three).

Description of the holotype.— ( Figs. 2–4 ) Adult male with both hemipenes partially everted, snout–vent length (SVL) 112 mm, head length from rostral to upper anterior edge of

auricular opening 25.2 mm, head width at broadest point 19.6 mm, head width/length ratio ¼ 78.4%, tail unbroken and unregenerated, tail length (TL) 154 mm (1.37 times SVL), and 81 caudal whorls. Supranasals 1/1, somewhat expanded medially; postnasals 2/2, upper slightly smaller than lower; one pair of anterior and posterior internasals situated between rostral and frontonasal; prefrontals over twice as large as posterior internasals, contacting each other medially; canthals 1/1, preventing contact between posterior internasal and prefrontal; loreals 1/1, about one-half size of cantholoreals, and contacting both postnasals; cantholoreals 1/1, extending onto dorsum of canthus rostralis, broadly contacting anterior median supraocular, canthal, prefrontal, and fifth supralabial; median supraoculars 5/5; lateral supraoculars 3/3; superciliaries 6/5, anteriormost on left side contacting cantholoreal and similar in length to adjoining superciliary, on right side fused with adjoining superciliary; preoculars 1/1; suboculars 2/2, posteriormost barely separat- ed from lowermost primary temporal by ninth (left side) or eighth (right side) supralabial; postoculars 3/3; frontal large, separated from frontonasal and interparietal; parietal separated from median supraoculars; one large occipital, slightly larger than interparietal, abnormally divided into a small triangular anterior scale and a much larger posterior scale; one transverse row of scales separating occipital from first transverse row of nuchals; primary temporals 4/4, only lowermost two contacting postoculars on each side; secondary temporals 4/4; tertiary temporals 4/4; supralabials 10/11, antepenultimate the posteriormost to reach orbit; infralabials 9/9; postmental divided; four pairs of enlarged chinshields posterior to postmental, posteriormost ones subequal in size to adjacent ones, separated by two scales; sublabials 4/4, anteriormost contacting third infralabial but not postmental.

Minimum longitudinal nuchal scale rows 6; transverse dorsal scale rows 32–33; longitudinal dorsal scale rows 16, arranged in slightly oblique longitudinal rows on sides of body; eight dorsal-most longitudinal scale rows strongly keeled, others entirely smooth or with faint partial keels; transverse ventral scale rows 33; longitudinal ventral scale rows 12; lateralmost row of ventral scales unexpanded relative to the adjacent medial row of ventral scales; head and several anterior rows of nuchals with well-developed osteoderms; more posteriorly on dorsum and flanks of body, osteoderms appear very weakly developed or absent; supra-auricular scales granular and non-protruding; about seven moderately sized scales (lateral neck scales) between lateral nuchals and first large scales on ventrolateral surface of neck; lateral neck scales with enlarged oblique row reaching the lateral nuchals, each scale in row 3 times larger than adjacent lateral neck scales; antebrachial from insertion of the forelimb to wrist 12–13; ventrolateral fold moderately well developed with small scales and granules interspersed in interstitial skin throughout ventrolateral fold; subdigital lamellae on fourth toes 21/21.

Coloration of the holotype.— ( Figs. 2–4 ) In life, body gray-brown, becoming bright yellow with scattered dark speckles on paravertebral scale rows and flanks. Body with distinct but narrow and uneven black chevron-shaped crossbands, often interrupted on flanks. Many vertebral and paravertebral dorsal scales with bright yellow posterior blotch, especially at midbody. Scales in and along ventrolateral fold bright to pale yellow with scattered dark speckles, some scales with black wedge-shaped markings at anterior margin. Lateral neck scales predominantly bright to pale yellow, but some entirely black scales consolidate into one or two oblique, oblong markings. Interstitial skin between lateral neck scales often dark gray and prominent. Partial black bar borders the dorsal-most lateral neck scales. Dorsal surface of forelimbs and hindlimbs mostly yellow, but many scales flecked with medium gray-brown, sometimes heavily, especially on the hindlimbs. Digits predominantly gray-brown with yellow flecks. Head predominantly cream-colored with yellow highlights and some gray-tinged scale margins, nearly all scales moderately to faintly rugose; rugosity accentuated by heavy black vermiculations, which extend onto all nuchal scales and across 2–3 transverse dorsal scale rows posterior to the forelimb insertion. Scales between orbit and rostral on sides of head cream to pale yellow with some darker marbling; rugosity and vermiculations absent. Tail medium gray-brown with yellow anterior margins or blotches on some lateral scales, particularly anterior third of tail. Tail with roughly 22 indistinct dark brown to black crossbands that do not or only faintly extend to venter, many reduced to a single dorsal blotch. Lower jaw, chin, and throat pale yellow, many scales flecked or blotched with dark gray, sometimes heavily. Venter of body and limbs bright yellow, some scales with dark gray flecks. Iris pale gray-green.

In preservative (ethanol after formalin), overall color pattern unchanged except all yellow dramatically faded to various shades of cream, and dorsum of back and tail with slight green tinge. Manus and pes cream-colored with faint rusty tinge. Subdigital lamellae medium gray-brown.

Morphological variation.— ( Figs. 3–4 ) All six paratypes similar to the holotype in most respects. Two adult males ( MZFC-HE 35665 , MZFZ 4408 ) with SVL 95.8 and 97.7 mm, head length from rostral to upper anterior edge of auricular opening 20.5 and 22.4 mm, head width at broadest point 16.3 and 16.6 mm, respectively, tail broken in MZFC-HE 35665 and broken and regenerated in MZFZ 4408 . One adult female ( MZFZ 4406 ) with SVL 86.6 mm, head length 19.1 mm, head width 14.4 mm, tail unbroken and unregenerated, TL 127.4 mm (1.47 times SVL). One subadult female ( MZFC-HE 35663 ) with SVL 81.1 mm, head length 17.6 mm, head width 13.1 mm, tail broken and regenerated, TL 104.2 mm (including 26.7 mm regenerated tissue). Two neonates ( MZFC-HE 35662 , MZFZ 4407 ) with SVL 44.2 and 45.6 mm, head length 10.5 and 10.8 mm, head width 7.1 and 7.5 mm, respectively, tail broken in MZFZ 4407 , and broken and regenerated in MZFC-HE 35662 .

The six paratypes closely resemble the holotype in scalation, with exceptions as follows. Supranasal markedly expanded medially on left side and contacting right posterior internasal in MZFC-HE 35662 and MZFZ 4407 ; postnasals subequal in size in MZFC-HE 35665 ; postnasal on right side absent in MZFZ 4406 ; prefrontals in narrow contact with each other in MZFC-HE 35662 ; cantholoreal in narrow contact with supralabials on right side and separated from supralabials on left side by expanded preocular in MZFZ 4408; superciliaries 6/ 4 in MZFC-HE 35662 , 5 / 5 in MZFZ 4408 , 6 / 5 in MZFZ 4407 , and 6/6 on all other paratypes; anteriormost superciliary markedly elongate on right side on MZFZ 4408 , due to aberrant fusion with adjacent superciliary; postoculars 2–4 on left side and 3–4 on right side across all paratypes (mean ¼ 3.1); frontal–interparietal contact absent in MZFZ 4407 , narrow contact in all other paratypes; parietal–median supraocular contact broad in MZFZ 4406 , narrow in MZFC-HE 35663 , absent in all other paratypes; one large occipital entire and not aberrantly divided in all paratypes except MZFC-HE 35663 , in which a small triangular scale separates the occipital from the interparietal (same as holotype); two transverse rows of scales separating occipital from first transverse row of nuchals in MZFC-HE 35665 , MZFZ 4406 , and MZFC-HE 35662 ; primary temporals 4/2 with uppermost on left side very small in MZFC-HE 35663 , 4 / 3 with medial temporals presumably fused on right side in MZFZ 4407 , 3 / 2 in MZFZ 4406 ; tertiary temporals 4/ 5 in MZFZ 4406 and MZFZ 4407 , 5 / 5 in MZFC-HE 35665 ; supralabials 10–12 (mean ¼ 10.8); infralabials 9–11 (mean ¼ 9.1); postmental single in MZFZ 4407 ; sublabials 4–5 (mean ¼ 4.5).

Transverse dorsal scale rows 30–34 (mean ¼ 32.3); transverse ventral scale rows 32 in MZFC-HE 35663 and MZFZ 4406; lateralmost row of ventral scales weakly enlarged overall in MZFC-HE 35662; osteoderms appear weakly developed in MZFC-HE 35662 and MZFZ 4407; lateral neck scales as few as 5 in MZFC-HE 35663; subdigital lamellae on fourth toes 17–22 (mean ¼ 19.8), excluding the counts from MZFZ 4408 which is missing both toe tips.

Color pattern variation.— In life, the two adult male paratypes ( MZFZ 4408 and MZFC-HE 35665 ) differ from the holotype as follows: dorsum medium gray; black chevron-shaped crossbands 0.5–2 scales wide, often extend to ventrolateral fold in MZFZ 4408 , reduced to narrow interrupted paravertebral dashes in MZFC-HE 35665 ; many scales in and along ventrolateral fold with black wedge-shaped anterior marking in MZFZ 4408 ; lateral neck scales mostly pale cream to whitish; partial black bar bordering dorsal-most lateral neck scales broken and indistinct in MZFC-HE 35665 ; dorsum of head with indistinct, arrowhead-shaped dark marking centered at occipital scale in MZFZ 4408 ; dorsum of head medium gray with cream highlights in MZFZ 4408 , cream with light gray margins on some scales in MZFC-HE 35665 ; black vermiculations extend across all nuchal scales and onto 3–4 transverse dorsal scale rows posterior to forelimb insertion in MZFZ 4408 ; sides of head from rostral to orbit medium gray with pale cream marbling in MZFZ 4408 , uniform pale gray in MZFC-HE 35665 ; supralabial scales posterior to orbit, and lowermost temporal scales, medium-gray with cream marbling and light to moderate black vermiculations in MZFZ 4408 , these scales cream to pale gray with vermiculations only on temporals in MZFC-HE 35665 ; anterior to autotomy point, tail with roughly 13 indistinct dark gray-brown crossbands in MZFZ 4408 , 3 heavily obscured dark gray crossbands in MZFC-HE 35665 ; ventral scales on head and body with hairline dark margins in MZFZ 4408 , only some scales with dark margins in MZFC-HE 35665 ; venter of head, body, and tail, and limbs mostly pale cream to whitish.

In life, the adult female paratype (MZFZ 4406) differs from the holotype as follows: body medium brown-gray with strong green tinge, becoming pale gray on paravertebral scale rows and flanks; chevron-shaped crossbands dark gray, 1–2 scales wide, often offset and partially fused along dorsal midline, terminate on flanks; posterolateral margins of some dark crossbands cream or pale yellow; scales in and along ventrolateral fold pale gray or cream, some with dark speckling; lateral neck scales mostly pale cream, lack adjacent dark dorsal bar; dorsum of all limbs pale gray with green tinge, hindlimbs blotched with medium gray-brown; digits tan to brown with green tinge; dorsum of head pale yellow with green tinge, most scales faintly rugose; rugosity accentuated by faint to moderate dark gray vermiculations, which extend onto most vertebral and paravertebral nuchal scales; sides of head from rostral to orbit to lowermost secondary temporal scale pale yellow with green tinge, with hairline black margins on many scales and some dark marks; temporal scales with moderate to weak black vermiculations, absent on supralabial scales; tail medium gray-brown becoming pale gray on sides with green tinge throughout; tail with roughly 24 broken, often offset crossbands, none reduced to a single dorsal blotch; lower jaw, chin, and throat cream to pale yellow, lack green tinge, lateralmost scales often with black to dark gray margins; venter of body, limbs, and tail pale yellow to cream, becoming pale gray laterally; dark crossbands on tail weakly visible on venter, most prominent on posterior half of tail.

In preservative, the subadult female paratype (MZFC-HE 35663) differs from the holotype as follows: body medium-brown, becoming slightly rusty brown on flanks; black chevron-shaped crossbands 0.5–1 scales wide, some broken at dorsal midline, usually with pale yellow or cream blotch or dash at posterolateral margin; scales in and along ventrolateral fold rusty brown with pale yellow to cream highlights; lateral neck scales mostly pale brown or cream, lack adjacent dark dorsal bar; interstitial skin on lateral neck inconspicuous, medium-gray, not forming oblique dark markings; limbs rusty brown, becoming dark gray posterolaterally; dorsum of head medium-brown with some gray highlights; black vermiculations weak on lateralmost nuchal scales, terminate at forelimb insertion; sides of head from rostral to orbit to lowermost secondary temporal scale cream with brown tinge, many scales with hairline dark gray margins; temporal scales with weak black vermiculations, absent on supralabial scales; tail medium-brown with rusty and gray highlights; anterior to autotomy point, tail with roughly 13 broken, often offset dark gray to black crossbands, none reduced to a single dorsal blotch, some with pale yellow to cream spot at posterior or posterolateral margin; regenerated portion of tail uniform medium-brown; lower jaw, chin, and throat pale cream to very pale brown with dark flecking; venter cream to pale gray or pale brown, often with moderate to heavy dark flecking.

In preservative, the two neonate paratypes (MZFZ 4407 and MZFC-HE 35662) differ from the holotype as follows: body pale gray to medium brown-gray lacking green tinge; dorsal crossbands black to dark gray, partly bordered posteriorly by pale gray to white; vertebral and paravertebral dorsal scales lack pale posterior blotches; lateral neck scales mostly pale gray; dorsum of all limbs pale gray to medium brown-gray, moderately to heavily flecked or blotched with black or dark gray; fingers and toes dark gray to medium brown-gray; dorsum of head same color as body, scales flat, most scales with hairline black margins, few scales rugose and only faintly so; rugosity accentuated with limited black vermiculations, not extending onto nuchal scales or transverse dorsal scales; sides of head from rostral to orbit to lowermost secondary temporal scale pale gray to pale brown-gray with hairline black margins on most scales, otherwise unmarked; tail same color as body with black to dark gray crossbands; regenerated portion of tail in MZFC-HE 35662 uniform dark gray; lower jaw, chin, and throat pale gray lacking green tinge; cream tinge on anterior half of jaw in MZFC-HE 35662; venter of body and limbs pale gray, nearly all scales moderately to heavily flecked with dark gray; venter of tail same as body except for uniform dark gray regenerated portion in MZFC-HE 35662; venter of tail mostly brown-gray with heavy dark gray flecking in MZFZ 4407.

In preservative (ethanol after formalin), all other paratypes maintain their general color pattern as described above, but like the holotype all yellow or cream is faded to pale cream or whitish, and brown areas are more gray and occasionally have a green tinge. Also, as in the holotype, manus and pes cream or whitish with faint rusty tinge, and subdigital lamellae medium gray-brown.

Etymology.— The specific epithet zongolica is a feminine singular adjective in the nominative case and refers to the Sierra de Zongolica of Veracruz, Mexico. This mountain range supports the only confirmed populations of the new species. The name ‘‘zongolica’’ appears to be derived from the words ‘‘tzoncolican’’ or ‘‘tzoncolihucan’’ in the Nahuatl language, which roughly translate as ‘‘where hair is braided’’ (Melgarejo Vivanco, 1950).

Distribution and ecology.— Based on vouchered material, the distribution of A. zongolica extends across less than 10 km in the Sierra de Zongolica from near Ayahuatulco to Huapango ( Fig. 5 ). All confirmed localities lie within the Río Alpatlahuaya drainage, and span an elevational range of 1,500 – 2,200 m. Suitable elevations above 1,500 m and mesic tropical forests are continuous between the known localities, and thus A. zongolica likely occurs in other regions of the Sierra de Zongolica. We are aware of records of Abronia from nearby forested areas of west-central Veracruz that also might represent A. zongolica . Pending detailed analysis of these populations and deposition of museum vouchers, we have considered their taxonomic allocation uncertain at this time. Additionally, Guzmán Guzmán (2011) published a photograph from an unspecified locality of what is identified as a female A. graminea , but which is actually an adult A. zongolica (likely a male) based on multiple diagnostic features as given in Table 2 .

Abronia zongolica is found in mature pine-oak forest (sensu Rzedowski, 2006), with dominant tree species including Quercus conspersa , Q. crassifolia , Q. laurina , and Q. rugosa ; the arboreal stratum also regularly contains Alnus acuminata , Cupressus benthamii , C. lindleyi , and Pinus patula ( Fig. 6 ). Epiphytes are typically abundant and primarily consist of bryophytes, but also include the bromeliad Tillandsia imperialis and fern Elaphoglossum paleaceum . Abronia zongolica seems to be both arboreal and diurnal. Most individuals were found hidden behind or within bromeliads on tree trunks or branches, ranging from the root or buttress level up to 4 m in height. Individuals were also directly observed while active by day amongst the branches of trees and shrubs. An analysis of fecal material from two individuals of A. zongolica (MZFZ-IMG 312 and 313) indicates that the species feeds on insects (Orthoptera, Coleoptera, Lepidoptera, and Hemiptera) along with other unidentified small invertebrates. To our knowledge, this is the first published wild dietary data for any arboreal species of Abronia . Like all arboreal congeners for which data exist ( Schmidt-Ballardo et al., 2015), A. zongolica is a viviparous species that gives birth in the spring: a captive female (MZFZ-IMG 309) birthed four neonates in early May that measured 30–33 mm SVL.

Abronia zongolica is sympatric with A. graminea in the municipalities of Astacinga and San Juan Texhuacán ( Fig. 5 ). Both species occupy similar forest microenvironments, but A. graminea is usually more abundant and is also distributed at higher elevations in coniferous forests, where A. zongolica appears to be absent. The only other gerrhonotine anguid lizard species that shares habitat with A. zongolica in the Sierra de Zongolica is the terrestrial Barisia imbricata .

Conservation.— None of the vouchered populations of A. zongolica occur in designated protected areas. However, the species might eventually be documented in the Parque Nacional Cañón del Río Blanco, the Reserva Ecológica Natural en la Cuenca Alta del Río Atoyac, or even the Reserva del Bicentenario ( Castillo-Hernández and Flores-Olvera, 2017; Pérez-Sato et al., 2018). Regionally, deforestation has caused extensive habitat loss and fragmentation ( Gómez-Díaz et al., 2018), including to the surroundings of all vouchered localities for A. zongolica . Due to agricultural demands and other livelihood requirements for the growing human population in the Sierra de Zongolica, we expect that this deforestation will continue. Climate change is also forecasted to dramatically reduce the area of cloud forests in this region ( Ponce-Reyes et al., 2012; Rojas-Soto et al., 2012). Because A. zongolica also occurs in more widespread mid-elevation forests, the threat posed by climate change remains difficult to quantify (but see Elsen et al., 2020). Additionally, the species could be threatened by direct killing due to mistaken beliefs that it is dangerously venomous ( Penguilly Macías et al., 2010) and by harvest for the pet trade ( Altherr, 2014; Auliya et al., 2016; Hernández Mares, 2018), although we consider these factors less important compared to deforestation and climate change. Nonetheless, based on the risk of hobbyist commercialization, we have preemptively masked the locality data reported herein by (1) rounding all GPS coordinates to the nearest hundredth of a decimal degree, and (2) not giving distances or cardinal directions from the nearest settlement or landmark.

Given this available threat data, together with the aforementioned distribution and ecology of A. zongolica , we propose its categorization under three relevant speciesimperilment frameworks. First, we suggest that A. zongolica be provisionally assessed as Endangered (B1ab[iii] þ 2ab[iii]) on the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species. Second, we evaluate A. zongolica as having an Environmental Vulnerability Score (EVS; Wilson et al., 2013) of 18 out of 20, placing it in the High Vulnerability category. Contributory geographic distribution, ecological distribution, and human persecution scores of 6, 8, and 4, respectively, substantiate this EVS, but if the species is shown to have a broader distribution and/or becomes commercially exploited for the pet trade, the latter two scores would warrant being updated to 7 and 6, respectively. Lastly, we recommend a categorization of Amenazada (Threatened) for A. zongolica on the Norma Oficial Mexicana list ( SEMARNAT, 2010), which is the only legally binding imperiled-species list in Mexico. We base this recommendation on the species meeting Criteria A.(I) þ B.(II) þ C.(II) þ D.(II) as defined by the Anexo Normativo I. All three proposed categorizations are consistent with those of many other arboreal species of Abronia ( SEMARNAT, 2010; Wilson et al., 2013; Clause et al., 2020).

Figures

FIG. 2. Abronia zongolica, new species, head of holotype (MZFC-HE 35664, head width 25.2 mm) in dorsal view (top), right lateral view (middle; image intentionally mirrored horizontally) and ventral view (bottom), in preservative. Scale bars represent 10 mm.

FIG. 3. Abronia zongolica, new species, color variation in life (photos not to scale). (A) Adult male holotype (MZFC-HE 35664, snout–vent length [SVL] 112 mm); (B) adult male paratype (MZFC-HE 35665, SVL 95.8 mm); (C) adult female paratype (MZFZ 4406, SVL 86.6 mm; image intentionally mirrored horizontally); (D) neonate paratype (MZFZ 4407, SVL 45.6 mm). Photos by Miguel Ángel de la Torre-Loranca and Antonio Esaú Valdenegro- Brito.

FIG. 4. Head comparison of adult Abronia zongolica and Abronia graminea, illustrating differences in (1) circumorbital area color, (2) upper and lower jaw color pattern, and (3) presence/absence of well-developed oblique row of enlarged lateral neck scales. Locality and voucher information for each image is as follows, listed from top-to-bottom. Abronia zongolica: Teopantzacoalco (paratype, MZFC-HE 35665), Ayahuatulco (holotype, MZFC-HE 35664), Huapango (referred specimen, MZFZ-IMG 310), Atiopa (paratype, MZFZ 4406), Huapango (referred specimen, MZFZ-IMG 311). Abronia graminea: El Sumidero (MZFC-HE 32991), Puerto del Aire (MZFZ-IMG 322), Acultzinapa (MZFZ-IMG 336), Puerto del Aire (Clause et al., 2016: fig. 2), Puerto del Aire (MZFZ-IMG 338). All photos taken within 1 month of capture. From top, first and third images of A. zongolica and fifth image of A. graminea intentionally mirrored horizontally. Photos by Miguel Ángel de la Torre-Loranca, Adam G. Clause, and Antonio Esaú Valdenegro- Brito.

FIG. 5. Geographic distribution of Abronia zongolica and proximate populations of the only known sympatric congener, A. graminea in Mexico. The star represents the type locality of A. zongolica. See Appendix 1 for locality information of mapped records of A. graminea.

FIG. 6. Habitat of Abronia zongolica at the type locality in Veracruz, Mexico.