Aneides (Castaneides) caryaensis, Patton & Apodaca & Corser & Wilson & Williams & Cameron & Wake, 2019

Patton, Austin, Apodaca, Joseph J., Corser, Jeffrey D., Wilson, Christopher R., Williams, Lori A., Cameron, Alan D. & Wake, David B., 2019, A New Green Salamander in the Southern Appalachians: Evolutionary History of Aneides aeneus and Implications for Management and Conservation with the Description of a Cryptic Microendemic Species, Copeia 107 (4), pp. 748-763 : 748-763

Aneides (Castaneides) caryaensis , new species urn:lsid:zoobank.org:act:99D016DA-6505-4787-BEEB-430C9834F530

Hickory Nut Gorge Green Salamander

Figures 4 , S 5 ; Tables 4, S 3

Holotype.— NCSM 33389 , adult male, USA, North Carolina, Rutherford County, from near Bat Cave (exact location withheld due to conservation concerns), 537 m elevation, J. R. Bailey , 22 June 1962.

Paratypes.— Herein, exact location data for populations other than the holotype of A. aeneus are withheld due to conservation concerns. USNM 446474 , same data as holotype ; MVZ 178584–178585 , North Carolina, Henderson County, A. Westerman, 1 October 1981 ; NCSM 33389– 33391 , North Carolina, Rutherford County, just E. of Henderson Co. line on north side of river, across from Bat Cave , near Bat Cave (ca. 1.9 air miles WNW Chimney Rock), J. R. Bailey, 22 June 1962 .

Diagnosis.— A member of the clade and genus Aneides , subgenus Castaneides , distinguished from the only other member of the subgenus, A. (C.) aeneus , by DNA sequence and preliminary morphological differences. Broadly similar in morphology to A. aeneus but differing in some aspects of coloration and in having 1) broader and elongated heads, 2) a greater number of maxillary and premaxillary teeth, 3) limbs that are slightly longer in relation to size, 4) broader shoulders, and 5) broader feet and longer toes.

Description.— Slender, very long-legged species of moderate size (maximum known standard length, SL, female 59.8 mm) with slender, whip-like tail (0.93–1.07 SL; longest in male holotype for which tail appears to have regenerated very early in life) and very long digits (longest toe 4.4 mm). Standard lengths (SL) of three sexually mature males are 48.5, 52.4, and 58.4 mm; four females are 52.8, 57.8, 58.9, and 59.8 mm. Head and body are strongly flattened; legs typically extended directly lateral from body. Long limbs overlap by 2.5 to 4 costal interspaces when adpressed to the sides of trunk. Head relatively broad (0.17–0.19, mean 0.18 SL); adductor muscles of jaw bulge outward behind eyes, slightly more in males than in females. Eyes large and prominent. Premaxillary teeth slightly enlarged in relation to those of plethodontids excluding other Aneides ; in males teeth penetrate upper lip. Maxillary teeth are in short row; posterior portion of maxillary bone is edentulous (as in fig. 2 of Wake, 1963). Anterior vomerine teeth in concave rows of medium length. Posterior vomerine teeth numerous, organized into unified patch on the roof of mouth. Mandibular teeth borne on dentary bone include two to five very large, conical, recurved teeth; other teeth small to moderate in size. Premaxillary teeth number range from three to seven in males, five to 17 in females. Maxillary teeth totals are 12 to 15 in males, 11 to 24 in females. Very small anterior vomerine teeth totals range from six to 17 in males and 12 to 19 in females. Only potential sexual dimorphism noted is somewhat higher tooth numbers in females and slightly larger jaw muscles in males.

Measurements (in mm), limb interval, and tooth counts of the male holotype.— SL 58.4, TL 62.6, HW 10.7, SG 15.0, HD 4.5, EL 3.5, EW 1.9, ES 3.8, ED 2.7, EN 3.1, IC 5.6, IO 3.4, SF 20.6, IN 3.0, SP 1.1, SW 6.6, SAV 53.8, AX 29.2, LI –4, CG 14, FLL 17.4, HLL 21.0, HAW 6.7, FW 8.8, T3 4.4, T5 3.2, TP 1.1, TW 3.6, TD 3.2. No mental gland evident. MT 8–7, DT 8 (4 large)– 6 (5 large), VT 6–9, PMT 3.

Coloration in life.— Ground color of dorsal surfaces is dark brownish-black. Dorsum covered by lichen-like patches of bright green to yellowish-green pigment. Flanks do not have dark pigment as in A. aeneus ; instead have light grayishyellow ground color on flanks and venter with loose suffusion of punctate melanophores. Density of punctate melanophores decreases on venter, especially near midline, so venter appears much lighter than other surfaces.

Comparisons.— Six adult males range from 49.9 to 55.3 mm SL (mean 52.8), similar to the three males of the new species (48.5–58.4, mean 53.1 mm); three adult females ranged from 44.8 and 53.0 mm (mean 49.5 mm), compared with the somewhat larger females of the new species (52.8–59.8, mean 57.3 mm). Some additional individuals from the Fort Payne area are mature at even smaller sizes; mental glands are present on males as small as 47.3 SL; a specimen from near Bat Cave has male cloacal morphology at 43.9 SL but no mental gland. These two populations are both near the southern limit of the genus in eastern North America. It thus appears that southern populations of Castaneides are smaller, on average, than more northern ones because A. aeneus is reported to reach 140 mm total length (the species occurs as far north as south-central Pennsylvania (39.978N) and as far south as west central Alabama (at least to 32.758N; Petranka, 1998; AmphibiaWeb, 2018). Juterbock (1989) reports males as large as 65.5 SL and females 65 SL in extreme southern Ohio.

The limbs are relatively longer in A. caryaensis relative to A. aeneus ; combined limb length is 0.63–0.67 SL (mean 0.65) in males and 0.61–0.62 SL (mean 0.62) in females, compared to 0.60–0.65 SL (mean 0.62) in males and 0.58–0.62 SL (mean 0.60) in females of the Fort Payne sample of A. aeneus . Additionally, the adpressed limbs cover 2.5 to 4 costal folds in the new species, in contrast to 1.5 to 2.5 in the Fort Payne ( A. aeneus ) sample. All specimens of the new species and of our Fort Payne sample have 14 costal grooves, which means that they have a high likelihood of having 15 trunk vertebrae. Wake (1963) reported counts of 15 (two specimens), 16 (10 specimens), and 17 (4 specimens) trunk vertebrae in individuals from across the range of A. aeneus .

Numbers of teeth are broadly similar in the two species. In A. aeneus , number of premaxillary teeth ranges from 3–9 and number of vomerine teeth ranges from 8–19. In A. caryaensis , number of premaxillary teeth ranges from 5–17 and number of vomerine teeth ranges from 6–19. Number of maxillary teeth differs among species, with A. aeneus possessing between 5 and 13, whereas A. caryaensis possesses between 11 and 24. This increase in the number of maxillary teeth in A. caryaensis relative to A. aeneus corresponds to a lengthening and widening of the head ( Table 4).

Aneides caryaensis is morphologically cryptic in relation to A. aeneus according to our preliminary analyses. However, there exist several notable differences among the two species ( Table 4; Fig. S5 ; see Data Accessibility). Outside of coloration differences ( Fig. 4 ), A. caryaensis possesses wider and longer heads (perhaps associated with more hypertrophied jaws), longer toes, as well as wider feet and bodies ( Table 4). In summary, A. caryaensis appears broader, albeit not significantly longer in total length ( Table 4). Notably, both PCA and LDA indicate that the two species are morphologically differentiated ( Fig. 5 ) using our preliminary data. A great amount of variance (68.9%) was explained by PC1, with an additional 8.8% explained by PC2 ( Fig. 5A ). No one variable loaded most heavily onto PC1, however. Our permutation procedure for LDA revealed that we are able to distinguish among species, on average, with 79% prediction accuracy ( Fig. 5B ).

Habitat and geographic range.— Observations recorded by the collector of the holotype, Joseph R. Bailey (field notes stored in North Carolina State Museum) include the following: ‘‘ June 22, 1962.—about 5–9 PM. Weather warm and fair. Conditions fairly moist.’’ Specimens collected ‘‘just above road on north side of [Broad] river in tight rock crevices in late afternoon. Only a few suitable crevices here. One individual taken at night from rock face on opposite side of river in [ Plethodon ] longicrus area. When tickled into sack below it, it flattened against rock and it was necessary to pry it off in contrast to longicrus of same size which would drop off.’’

Co-occurring species.— Three other plethodontid salamander species are commonly encountered in syntopy with A. caryaensis : Plethodon amplus ( Plethodon jordani species complex), Desmognathus cf. carolinensis (possible intergrade with Desmognathus ocoee ), and a species that occurs in microsympatry and is currently assigned to Plethodon yonahlossee , but that was described originally as Plethodon longicrus ( Adler and Dennis, 1962) . Importantly, the type locality of A. caryaensis (the Hickory Nut Gorge) is also the type locality of P. longicrus . It is noteworthy that these three species are either endemic to the range of A. caryaensis or are differentiated to the extent that they either were once recognized as distinct taxa or are currently of undetermined status.

Etymology.— Named after the Hickory Nut Gorge of Western North Carolina to which the species is restricted. We allude to this locality by referencing the genus Hickory ( Carya ), after which the locality is named.

Figures

FIG. 4. Images representing Aneides aeneus (A) and A. caryaensis (B). Aneides caryaensis is characterized by smaller and less connected lichen-like patches of bright green to yellowish-green pigment.

FIG. 5. Results of Principal Components Analysis (PCA) and Linear Discriminant Analysis (LDA) using 14 morphological characters. For both analyses, data were normalized where possible and necessary (longest toe, 5th toe log-transformed; adpressed limbs converted to absolute value and then log-transformed). (A) PCA with points and normal data ellipses colored by species. (B) Density plot of prediction accuracy by LDA across 1,000 permutations of samples for the training and prediction sets.