A New Species of Subterranean Blind Salamander

Herpetologists' League

A New Species of Subterranean Blind Salamander (Plethodontidae: Hemidactyliini: Eurycea: Typhlomolge) from Austin, Texas, and A Systematic Revision of Central Texas Paedomorphic Salamanders Author(s): David M. Hillis, Dee Ann Chamberlain, Thomas P. Wilcox, Paul T. Chippindale Source: Herpetologica, Vol. 57, No. 3 (Sep., 2001), pp. 266-280 Published by: Herpetologists' League Stable URL: http://www.jstor.org/stable/3893095 . Accessed: 04/08/2011 09:48

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http://www.jstor.org Herpetologica, 57(3), 2001, 266-280 C) 2001 by The Herpetologists' League, Inc.

A NEW SPECIES OF SUBTERRANEAN BLIND SALAMANDER (PLETHODONTIDAE: HEMIDACTYLIINI: EURYCEA: TYPHLOMOLGE) FROM AUSTIN, TEXAS, AND A SYSTEMATIC REVISION OF CENTRAL TEXAS PAEDOMORPHIC SALAMANDERS

DAVID M. HILLIS', DEE ANN CHAMBERLAIN', THOMAS P. WILCOX', AND PAUL T. CHIPPINDALE2 'Section of Integrative Biology, School of Biological Sciences, The University of Texas at Austin, Austin, TX 78712, USA 2Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA

ABSTRACT: We describe a new species of salamander (Eurycea) from the Barton Springs segment of the Edwards Aquifer, Austin, Texas, USA. The new species is most closely related to Eurycea (Typhlomolge) rathbuni from subterranean waters around San Marcos, Texas, and like that species lacks external eyes and shows other morphological features associated with subterranean life. The new species is easily distinguished on the basis of morphology from all previously described species of salamanders, and in particular is easily distinguished from its closest relatives, E. (Ty- phlomolge) rathbuni and E. (Typhlomolge) robusta, as well as the sympatric E. sosorum. We used sequences of the mitochondrial cytochrome b gene to infer the phylogeny of described species of central Texas Eurycea, and these data support the major groups reported previously on the basis of other DNA and allozyme data. We also define names for the major clades of central Texas Eurycea. Key words: Caudata; Plethodontidae; Hemidactyliini; Eurycea waterlooensis new species; Blep- simolge new clade; Notiomolge new clade; Paedomolge new clade; Septentriomolge new clade; Ty- phlomolge clade definition; Eurycea clade definition; Endangered species; Texas; Barton Springs

"[Eurycea neotenes] was described in Sep- tenes, was not discovered at Helotes until tember, 1937, on the basis of nine speci- 1936 (Bishop and Wright, 1937; see also mens taken in April, 1936, from Culebra quote above by L. T. Murray), and some- Creek, 5 miles north of Helotes, Bexar how herpetologists missed the abundant County, Texas .... This is a very interest- Eurycea nana (sympatric with E. rathbuni ing discovery; and surprising, since no at San Marcos Springs) until 1938 (Bishop, small area in Texas has been more care- 1941). Both of these localities were visited fully collected over than that about Helo- by numerous herpetologists for many years tes. Gabriel Marnock made of it an historic prior to the discovery of these common region that many herpetologists have vis- animals. Perhaps even more surprising is ited as a shrine; yet so evident an animal the case of Eurycea sosorum from Barton as this salamander had escaped notice un- Springs, in downtown Austin, Texas. De- til 1936." L. T. Murray (1939:5) spite the fact that dozens of herpetologists received the Ph.D. from the 1940s to the MANY distinct species of paedomorphic 1990s at The University of Texas at Austin, salamanders from the springs and caves of this species was not described until 1993 the Edwards Plateau in central Texas have (Chippindale et al., 1993). been overlooked by generations of herpe- For several years prior to the initial pe- tologists. The first member of this group titions to list Eurycea sosorum as a federal to be described was Eurycea (Typhlomol- Endangered Species in 1992, cleaning ge) rathbuni, which was collected from an practices at Barton Springs had reduced artesian well at the Federal Fish hatchery most of the observable population of sal- in San Marcos, Texas in the 1890s (Stejne- amanders to a small number of individuals ger, 1896). However, the first surface spe- around the main spring outlet (Parthenia cies of paedomorphic salamander de- Spring). Changes in cleaning practices scribed from central Texas, Eurycea neo- (elimination of the use of chlorine, and the

266 September 2001] HERPETOLOGICA 267 reduction in mechanical disturbance and Springs). Here we name the new species the use of high-pressure hoses) from from Barton Springs. 1992-1997 (when the species was formally listed as Endangered) resulted in some re- METHODS covery of the population. The biggest We sequenced copies of the mitochon- threat to the continued existence of this drial cytochrome b gene from individuals species now comes from development of of all the described species of central Tex- the recharge zone of the Barton Springs as Eurycea (except for Eurycea robusta, segment of the Edwards Aquifer, which which is known only from the holotype; has resulted in some new decline of the see Appendix I for a listing of specimens). population (especially from increased sil- We amplified a 1026-1141 bp fragment of tation of the aquifer and springs). None- the mitochondrial cytochrome b gene us- theless, efforts to protect Eurycea sosorum ing the forward primer MVZ15 (GAAC- allowed some recovery of the species in TAATGGCCCACACWWTAC GNAA; the mid-1990s from the extremely small Moritz et al., 1992) and the reverse primer population sizes that resulted from earlier HEMTHRREV (CTTTGRCTTACAAG- cleaning practices in the pool area. The GYCAATG) or EURCB9 (GATTGAG- City of Austin has protected one of the GAYRCTTGTCCAATTTC). We used outlets of Barton Springs (Sunken Gar- standard PCR conditions (Palumbi, 1996) dens Spring) as a salamander refuge since with annealing temperatures of 45-52 C 1998, and the city plans to restore another and extension times of 1-1.5 min, and outlet (Eliza Spring) to a more natural standard automated sequencing protocols state that is expected to benefit salaman- (Li-Cor and PE Biosystems). Phylogenetic der populations. Prior to its protection, analyses were performed using the Sunken Gardens Spring was heavily af- MVZ15-EURCB9 fragment (1026 bp). fected by humans, who often used the Phylogenetic analyses (parsimony and spring for bathing and even washing maximum-likelihood criteria) were con- clothes, and most of Eliza Spring was en- ducted using PAUP* (v4.b4, Swofford, cased in concrete in the early 1900s. 1998). An exact solution for the parsimony Since the description of Eurycea soso- analysis (with equal character weighting) rum, there have been occasional sightings was found using the branch-and-bound of juveniles of a morphologically distinct search algorithm. The maximum-likeli- paedomorphic salamander at Barton hood analysis was based on the GTR+F+ Springs that resembles E. (Typhlomolge) INV model of sequence evolution (Swof- rathbuni more than E. sosorum. However, ford et al., 1996). Rate heterogeneity was given the Endangered status of Eurycea modeled using four evolutionary rate clas- sosorum, collection of salamanders at Bar- ses, including an invariant class. For the ton Springs has been closely regulated and maximum likelihood analysis, we per- restricted. Combined with the fact that formed heuristic searches (TBR branch this second species is only very rarely seen swapping) on five stepwise addition trees at the surface, and typically only juveniles based on random taxon addition. We con- are seen in the spring outlets, obtaining ducted 500 bootstrap replicates for parsi- sufficient material for its description has mony and 100 bootstrap replicates for been difficult. However, we have now ver- maximum likelihood analyses (Felsenstein, ified that a parallel situation exists between 1985). Barton Springs and San Marcos Springs. Measurements were made with digital In each case, there are two species of sal- calipers to the nearest 0.1 mm. Measure- amanders: one surface species with func- ments used to compare species included tional image-forming eyes (E. sosorum at total length (TL: tip of snout to tip of tail), Barton Springs and E. nana at San Marcos standard length (SL: tip of snout to pos- Springs) and one blind subterranean spe- terior margin of cloaca), axilla-groin cies (an undescribed species at Barton length, trunk width (at maximum point be- Springs and E. rathbuni at San Marcos tween axilla and groin), width of the upper 268 HERPETOLOGICA [Vol. 57, No. 3

,2 ~ ~ ~ ~ ~ ~ B

B D

ji~~~~ ~Scale 2 cm (Aand B); 1 cm (Cand D)

FIG. 1 Comparison of the dorsal and lateral aspects of the heads and forelimbs of (A) Eurycea rathbuni (TNHC 51175, from Rattlesnake Cave, Hays Co., Texas); (B) E. robussta (TNHC 20255, holote); (C) E. sosorum (TNHC 51184, holotype); and (D) E. waterlooensis (TNHC 60201, holotype). Note that (A) and (B) are at 0.5x scale compared to (C) and (D).

forelimb (at maximum), head width at = 62.5 mm); TNHC 60203, a juvenile (to- eyes, maximum head width, height of the tal length 18.0 mm) collected 3 May dorsal and ventral tail fins at mid-tail, and 1999 from Barton Springs Pool, Zilker height of the caudal musculature at mid- Park, Austin, Travis Co., Texas; and TNHC tail. 60320, a juvenile (total length = 13.0 mm) collected 27 August 1998 from Eliza SPECIES DESCRIPTION Spring, Zilker Park, Austin, Travis Co., Eurycea waterlooensis sp. nov. Texas. All specimens of this species have Holotype.-TNHC 60201 (Fig. ID), been collected by employees of the City of collected 13 January 1998 by Robert Han- Austin's Watershed Protection Depart- sen and Dee Ann Chamberlain from ment (Robert Hansen and Dee Ann Sunken Gardens Spring (Fig. 2), an outlet Chamberlain) under a permit issued by of Barton Springs, Zilker Park, Austin, the United States Fish and Wildlife Ser- Travis Co., Texas. This individual was a ju- vice (Endangered Species Permit TE venile (27.5 mm total length) when cap- 833851). tured, but was raised in captivity until 13 Etymology.-In 1837 or 1838, Mira- November 1998 (to a total length of 68.6 beau Buonaparte Lamar, then Vice Presi- mm), when the distal 2-mm of its tail was dent of the Republic of Texas, went in removed for molecular analysis and the search of a new site for the capital city on specimen was preserved. the western frontier of the Republic. He Paratypes.-TNHC 60202, collected 22 found a site along the Colorado River in- January 1999 from the type locality and habited by Joseph Harrell on the north preserved 16 December 1999 (total length bank of the river, and William and Stacy Septemnber2001] HERPETOLOGICA 269

FIG. 2.-Sunken Gardens Spring salamander refuge, the type locality of Eurycea waterlooensis.

Barton, who had settled on the south bank dark eye spots that are present are covered of the river around what would become by undifferentiated skin). The dark eye known as Barton Springs. When Lamar spots are superficially indistinguishable became President of the Republic of Texas from those in E. rathbuni, whereas the in December 1838, he directed a commis- vestigial eye spots of E. robusta are pro- sion to visit the site, and in January 1839 portionally smaller and less visible (Fig. 1). they selected the site for the new capital Other described species of Eurycea typi- and named it Waterloo. The Congress of cally have external eyes with well devel- Texas changed the name of the city to Aus- oped lenses, although lenses are absent in tin. Eurycea waterlooensis, therefore, is some specimens of E. tridentifera (the named after the original name of Austin, dark eye spots are proportionally much Texas, whose citizens have long protected larger in E. tridentifera than in E. water- Barton Springs for its natural beauty, its looensis, E. rathbuni, or E. robusta). We clean, cool water, and its unique biological call E. waterlooensis a "blind salamander," diversity. We recommend that this species following the practice with E. rathbuni be known by the common name of Austin and E. robusta, because all three species Blind Salamander. lack image-forming lenses. However, all Diagnosis.-Eurycea waterlooensis is three species do have small eye spots be- easily distinguished from all other species low the surface of the skin (presumably of Eurycea by the following combination homologous with the pigment layer of the of morphological characters. (1) Eurycea retina), and may be able to detect the waterlooensis is perennibranchiate, which presence or absence of light. (3) There are distinguishes it from most species of Eu- 12 costal grooves in E. waterlooensis, as in rycea from outside the Edwards Plateau E. robusta and E. rathbuni. Most other region of central Texas. (2) External eyes species of paedomorphic Eurycea have 13 are absent (there are no lenses, and the or more costal grooves. Most specimens of 270 HERPETOLOGICA [Vol. 57, No. 3

the sympatric E. sosorum have 14-15 cos- and tail. The only adult specimen of E. wa- tal grooves, although Chippindale et al. terlooensis collected in the wild appears (1993) reported single specimens of this somewhat darker in coloration (the laven- species with 13 and 16 costal grooves. (4) der appearance is more strongly devel- The limbs of E. waterlooensis are propor- oped) compared to the juveniles of this tionally much shorter than in E. rathbuni species, or compared to the adults that or E. robusta. The adpressed limbs of E. have been raised in captivity. Eurycea wa- rathbuni overlap by 5-9 costal folds; those terlooensis can also be distinguished from of the single specimen of E. robusta over- E. rathbuni and E. robusta by its much lap by one costal fold; and the adpressed shorter limbs (see above) and by propor- limbs of E. waterlooensis are separated by tional differences in head and body shape. 1-3 costal folds. (5) The tail fins of E. wa- The head, body, and limbs of E. robusta terlooensis are weakly developed; the ven- are much thicker and heavier than in ei- tral portion of the tail fin is present only ther E. waterlooensis or E. rathbuni. The on the posterior half of the tail, and the trunk width is 45.8% of the axilla-groin dorsal portion is very low or absent on the length in the single specimen of E. robus- anterior half of the tail. In contrast, most ta, compared to 34.5% in 10 specimens of other species of paedomorphic Eurycea E. rathbuni measured by Potter and Sweet (including the closest relatives E. rathbuni (1981), and 30.3% in the holotype of E. and E. robusta, as well as the sympatric E. waterlooensis. The width of the upper sosorum) typically have well-developed tail forelimb is 19.1% of the forearm length in fins that are distributed along the entire E. robusta, compared to 7.4% in E. rath- length of the tail (although fin develop- buni and 11.4% in E. waterlooensis. The ment is somewhat variable in E. sosorum). head of E. rathbuni is nearly as wide at At mid-tail, the relative proportions of the the eye spots as at its widest point (just in heights of the dorsal tail fin, the caudal front of the gills), whereas in E. water- musculature, and the ventral tail fin are looensis and E. robusta, the head is mark- approximately 0.31-0.54-0.15 in the ho- edly narrower at the eye spots than at the lotype of E. robusta, 0.26-0.60-0.14 in widest point in front of the gills (Fig. 1). specimens of E. rathbuni, and 0.05-0.95- As described above, the tail fins of E. wa- 0.0 in the holotype of E. waterlooensis. terlooensis are much more weakly devel- In general appearance and coloration, oped than in E. rathbuni or E. robusta. E. waterlooensis is most similar to E. rath- The hind digits of E. waterlooensis also buni and E. robusta. These three species differ from both E. rathbuni and E. ro- share a lateral expansion of the anterior busta in relative length; the hind digits of cranial elements that produce an extended E. waterlooensis are 4-3-2-5-1 in order of snout (Fig. 1). Eurycea rathbuni and E. decreasing length, whereas in the other waterlooensis (and presumably E. robusta, two species the digits are 3-4-2-5-1. The which we have not seen in life) have a re- gills on the known specimens of E. water- flective, pearly white appearance which looensis are also proportionally smaller apparently results from the transparent than in either E. robusta or E. rathbuni skin and the underlying reflective connec- (Fig. 1). tive tissues. However, specimens of E. wa- All known specimens of E. waterlooen- terlooensis show more pigmentation than sis are smaller than adults of E. rathbuni either E. rathbuni or E. robusta, and live or E. robusta, although E. waterlooensis specimens of E. waterlooensis exhibit a grows considerably larger than E. sosorum. translucent or reflective lavender colora- The largest preserved specimen of E. wa- tion in the dorsal skin above the pearly terlooensis (the holotype) has a standard white luster, a result of a light but nearly length (SL) of 35.6 mm and total length uniform distribution of melanophores in (TL) of 66.6 mm (68.6 mm before the tail the skin. In addition, some specimens of tip was removed), and the largest living E. waterlooensis exhibit a distinct row of specimen in captivity was approximately iridophores along each side of the body 81 mm TL in December 2000. In contrast, September 2001] HERPETOLOGICA 271 the holotype of E. robusta has a SL of 57.1 length: 11.2 mm; upper hindlimb width: mm and TL of 100.8 mm, and 10 speci- 1.5 mm; tail length: 32.7 mm (34.7 mm mens of E. rathbuni measured by Potter before removal of the tail tip). and Sweet (1981) had a mean SL of 56.1 There are 12 costal grooves, although mm and TL of 100.9 mm. Five specimens the anterior-most and posterior-most cos- of E. waterlooensis maintained alive in tal grooves are very weakly developed, so captivity grew rapidly for -8 mo from -15 that only 10 costal grooves are readily ap- mm to -60 mm TL, after which growth parent. There are four digits on the fore- slowed to -1 mm/mo; we conclude from limbs, 3-2-4-1 in order of decreasing these observations that individuals likely length, and five digits on the hindlimbs, 4- reach sexual maturity at about 60 mm TL. 3-2-5-1 in order of decreasing length. The The only adult of E. waterlooensis collect- snout is elongate and flattened, and the ed in the wild was 66 mm TL. body is flattened ventrally. The tail fins are The only known species of aquatic sal- weakly developed and clearly evident only amander that is sympatric with Eurycea on the posterior half of the tail. waterlooensis is E. sosorum (Fig. 3). These In life, the overall appearance of the ho- two species are easily distinguished by the lotype was pearly white with a light lav- lack of external eyes and the pronounced ender hue, with lightly pigmented skin and extension of the snout in E. waterlooensis a few lateral highly reflective white spots (Figs. 1, 3), as well as its smaller number formed by iridophores, which were more of costal grooves (12, versus 13-16 in E. concentrated on the tail. In the preserved sosorum). Coloration of E. sosorum is typ- specimen, small dark eye spots are evi- ically darker than in E. waterlooensis, with dent, but they are buried deep beneath varying degrees of dorsal blotching and the skin. The dorsal surfaces of the head, mottling produced from an irregular pat- body, and tail are covered with a relatively tern of melanophores, with areas of high uniform distribution of melanophores at a concentrations of silvery-white iridop- density of approximately 25/mm2. There hores. In contrast, E. waterlooensis exhib- are a few light colored spots, lacking in its the overall pearly white luster also seen melanophores, that correspond to the lo- in E. rathbuni, apparently the result of the cation of the reflective iridophores that light-reflective connective tissue that un- were evident in life. The ventral surfaces derlies the skin. There is a relatively uni- of the head and body are almost complete- form but light distribution of melano- ly lacking melanophores, and in life the phores across the dorsal surfaces of the heart and other internal organs were visi- head, body, and tail of E. waterlooensis ble through the skin. The gills were bright (ventral surfaces are unpigmented). In ad- red in life. dition, there are typically a few spots of Variation. -The paratypes are similar to highly reflective iridophores along the side the holotype in most respects, although of the body of E. waterlooensis, and a TNHC 60202 is darker overall. TNHC higher concentration of these spots on the 60203 and 60320 are juveniles, in which tail. the eye spots appear proportionally larger Description of the holotype.-Standard in relation to the head than in the adults; length: 35.6 mm; total length: 66.6 mm the tail fins are proportionally larger in the (68.6 mm before tail tip was removed); juvenile specimens as well. Six additional snout to gular fold: 8.6 mm; snout to base specimens are currently maintained alive of third gill ramus: 11.9 mm; eye spot to in captivity by the City of Austin; as of De- base of third gill ramus: 8.5 mm; width of cember 2000, these specimens were 81 head at level of the jaw articulation: 7.3 mm, 80 mm, 68 mm, 66 mm, 50 mm, and mm; diameter of eye spots: 0.45 mm; dis- 30 mm in total length. The live specimens tance between eye spots: 3.1 mm; maxi- resemble the other known specimens, al- mum trunk width: 5.7 mm; axilla-groin though the largest specimen collected length: 18.8 mm; forelimb length: 8.8 mm; from the wild (66 mm) is the darkest in- upper forelimb width: 1.0 mm; hindlimb dividual. The light dorsolateral islands of 272 HERPETOLOGICA [Vol. 57, No. 3

FIG. 3.-Comparison of the sympatric species Eurycea sosorum (top) and E. waterlooensis (bottom). Both of these specimens are part of the captive breeding program for these species administered by the City of Austin. iridophores in three of the living speci- is somewhat variable among the known mens are present as pairs of light spots ex- specimens, although all have weakly de- tending along each side of the back, and veloped tail fins in comparison to E. rath- these spots are more numerous and con- buni or E. robusta. In most of the speci- centrated on the tail. Tail fin development mens, there is a very shallow dorsal tail fin September 2001] HERPETOLOGICA 273

that extends to near the base of the tail, material after it was brought into captivity. but the ventral tail fin does not extend an- In captivity, this species feeds readily on a terior to the mid-point of the tail. wide variety of small aquatic invertebrates. Distribution and natural history.-This As part of the recovery efforts for the species has been observed at three of the endangered Eurycea sosorum, the City of four outlets of Barton Springs: Parthenia Austin is developing a captive breeding (Main) Spring, which forms Barton program for the species. This program also Springs Pool (photograph in Chippindale now includes E. waterlooensis, and six of et al., 1993); Eliza Spring (photograph in the known individuals are currently main- Chippindale et al., 1993); and Sunken tained alive as part of this program. Dis- Gardens (Old Mill) Spring (Fig. 2). To turbances associated with human activities date, E. sosorum is the only species of sal- in Barton Springs Pool are probably less amander that has been observed at the likely to affect E. waterlooensis than E. so- Upper Spring outlet of Barton Springs. sorum, although both species are negative- City of Austin employees have conducted ly affected by changes in the Barton a monthly salamander census of the four Springs segment of the Edwards Aquifer outlets of Barton Springs from 1997 to the that result from development in the represent. During the period of July 1998- charge and contributing zones of the aqui- December 2000 (when records of E. so- fer. In particular, the rapidly increasing sorum and E. waterlooensis were differ- levels of siltation in Barton Springs and the entiated), 1535 salamanders were ob- aquifer seen over the past decade are a served (many of these probably represent cause for concern regarding the continued repeat observations in different months), existence of these two species. of which 1518 were E. sosorum and only Captive specimens of E. waterlooensis 17 were E. waterlooensis. However, these often crawl out of the water onto the sides observations are likely a reflection of the of an aquarium, where they use the side respective habitats of the two species: E. of their flattened muscular tails to adhere sosorum is primarily a surface species, to the wet surface of the glass. Individuals whereas E. waterlooensis, like its relative spend many minutes at a time out of water E. rathbuni, is probably mostly restricted if humidity is near 100%. to subterranean cavities of the Edwards Aquifer. All but one of the specimens of PHYLOGENETIC RELATIONSHIPS AND E. waterlooensis observed in the springs HIGHER TAXONOMY have been juveniles, which likely were Our inferred phylogeny of the central flushed out of the aquifer accidentally. Of Texas paedomorphic salamanders based on the 18 documented observations of E. wa- cytochrome b sequences is shown in Fig. terlooensis (the 17 observations from July 4. There was a single best maximum-like- 1998-December 2000 plus the holotype lihood solution (Fig. 4), and four equally collected in January 1998), 14 were at short parsimony trees. The four parsimony Sunken Gardens Spring, three in the main solutions differed among themselves in the pool (Parthenia Spring), and one in Eliza relationships among E. tridentifera, E. la- Spring. Specimens of E. waterlooensis titans, E. pterophila, and E. neotenes, al- have been observed throughout much of though one of the four solutions for these the year, although 12 of 18 observations taxa was identical to the maximum likeli- were in the winter months of November, hood tree shown in Fig. 4. In addition, December, and January, and four of the each of the parsimony trees switched the remaining observations were in the mid- positions of E. chisholmensis and E. nauf- summer months of July and August (the ragia compared to the maximum likeli- two remaining observations were in Feb- hood tree. However, all the deeper ruary and May). branches of the tree were the same in both The wild-caught adult specimen of E. analyses, and most of the major groups waterlooensis defecated the remains of were supported by high bootstrap propor- amphipods, ostracods, copepods, and plant tions in both analyses (Fig. 4). Among the 274 HERPETOLOGICA [Vol. 57, No. 3

E. chisholmensis 100 100 E tonkawae 31 67 E. naufragia

E rathbuni 100 100 E. rathbuni 100 98 E. waterlooensis 100 100 E. waterlooensis

E. nana

E. tridentifera 100 47 97 90 61 E. latitans 42 86 E. pterophila

100 100 6 8 E. neotenes 51 E. sosorum

61 Eurycea sp. (Pedernales) TroughSpring 98 E troglodytes 94 Sutherland complex HollowSpring E. multiplicata

10 changes

FIG. 4.-Phylogenetic relationships of the central Texas clade of paedomorphic Eurycea, based on sequences of the cytochrome b gene (museum voucher numbers and GenBank accession numbers are given in Appendix I). The branching topology of the tree shown is based on the best maximum likelihood solution; branch lengths are based on character reconstructions under parsimony. The numbers adjacent to branches indicate bootstrap support for the respective clades, with bootstrap values for the parsimony analysis shown on top and bootstrap values for the maximum likelihood analysis shown below. September 2001] HERPETOLOGICA 275

Septentriomolge >& E. chisholmensis E. tonkawae E. naufragia

Paedomolge Typhlomolge E. rathbuni E. robusta E. waterlooensis

Eurycea

NotiomolgeNotiomolge | F ~~~~E.E nanatride ntife ra E. latitans E. pterophila E. neotenes E. sosorum Blepsimolge E. troglodytes

E. lucifuga (and other Eurycea)

FIG. 5.-Nomenclature of the clades of central Texas Eurycea. The node-based clade names are defined in the text.

species in our analysis, E. waterlooensis is logenetic relationships inferred by Chip- most closely related to E. rathbuni, and pindale et al. (2000), because they found this grouping was supported in ?98% of T rathbuni to be more closely related to bootstrap replicates (both parsimony and some species of Eurycea than all the spe- maximum likelihood analyses). However, cies of Eurycea are to one another (see because we were unable to include E. ro- also Fig. 4). However, this change is re- busta in our analysis, the relationships quired only because of the ranked nature among E. rathbuni, E. robusta, and E. wa- of Linnaean nomenclature. The name Ty- terlooensis remain unclear. phlomolge is still available for a monophy- Mitchell and Reddell (1965) proposed letic group within Eurycea (Fig. 5), re- that Typhlomolge rathbuni (the type spe- gardless of the rank to which it is assigned. cies of Typhlomolge by monotypy) be According to the rules of the International placed in the genus Eurycea. This taxo- Code of Zoological Nomenclature (ICZN, nomic change was supported by the phy- 1999), any uninominal name of a ". . . ge- 276 HERPETOLOGICA [Vol. 57, No. 3

nus-group division of a genus, even if it is genetic tree or indenting conventions. Al- proposed for a secondary (or further) sub- though we look forward to modifications division, is deemed to be a subgeneric of the rules of nomenclature to allow the name even if the division is denoted by a use of unranked names, we here follow the term such as 'section' or 'division' rules of the ICZN in naming groups within (Art. 10.4). Therefore, if the name Ty- Eurycea. However, we choose to define all phlomolge is associated with a group with- clade names phylogenetically (in addition in the genus Eurycea, then Typhlomolge is to the ICZN requirements of a diagnosis a subgenus under ICZN rules, even if and type species designation) so that they more or less inclusive names are also pro- may also be used under a phylogenetic sys- posed within Eurycea. A name for a more tem of nomenclature and will be clear in inclusive clade that includes Typhlomolge their phylogenetic meaning. (but is still part of Eurycea) is also a sub- We here define Typhlomolge Stejneger genus under the ICZN rules (even though 1896 as "the last common ancestor of Eu- we may refer to it as a section or some rycea rathbuni (Stejneger 1896), Eurycea other informal rank). robusta (Potter and Sweet 1981), and Eu- The name Typhlomolge could be ap- rycea waterlooensis Hillis, Chamberlain, plied to several different clades that in- Wilcox, and Chippindale 2001, and all of clude the type species (E. rathbuni). How- the descendants of that common ances- ever, the characters that have been used to tor." We define E. robusta as part of this diagnose this group (e.g., by Potter and group, even though we have no sequence Sweet, 1981) indicate that the name Ty- data for this species, on the basis of the phlomolge logically should be associated morphological evidence described by Pot- with the clade that contains E. rathbuni, ter and Sweet (1981) in support of Ty- E. robusta, and E. waterlooensis (Fig. 5). phlomolge. We include all three species in This group, however, is phylogenetically the definition for the clade Typhlomolge, imbedded deep within Eurycea. Under because the relationships among the three the Code, the choice of one genus (for Eu- species are not clear, and any two species rycea) or several genera (for Eurycea, Ty- potentially could define a clade that ex- phlomolge, etc.) is subjective. If Eurycea is cludes the third species. The name Ty- ranked as a genus and Typhlomolge as a phlomolge is formed from the Greek ty- subgenus, then the treatment of interme- phlos, meaning "blind," and the generic diate clades between Eurycea and Ty- name Molge Merrem 1820 (a synonym of phlomolge is somewhat problematic. Un- Triturus Rafinesque 1815), which in turn der the Code, these intermediate groups is derived from the German word molch, will also be subgenera (even if named as meaning salamander or monster (Stejne- sections or divisions), thus creating sub- ger, 1907). Because molch, and therefore genera within subgenera. A phylogenetic Typhlomolge, is masculine, the original system of nomenclature that does not re- name Typhlomolge robusta was misfor- quire ranks (e.g., de Queiroz and Gauthier med, and should have been Typhlomolge 1990, 1992, 1994; see also http:// robustus. However, the combination Eu- www.ohiou.edu/phylocode/) would elimi- rycea robusta matches in gender, so no nate the subjective nature of ranking de- change is needed in the present combi- cisions, and would not create misleading nation under ICZN rules. The known con- ranks (e.g., subgenera that are imbedded tent of Typhlomolge is limited to E. rath- within other subgenera). Under such a sys- buni, E. robusta, and E. waterlooensis. We tem, the name Typhlomolge would be used also define Eurycea Rafinesque 1822 as to refer to a distinctive monophyletic "the last common ancestor of Eurycea group of subterranean blind salamanders rathbuni (Stejneger 1896) and Eurycea lu- (Fig. 5), without reference to a particular cifuga Rafinesque 1822, and all of the de- subjective rank. The hierarchical relation- scendants of that common ancestor." Eu- ships of this taxon to others could be de- rycea lucifuga is the type species of Eu- picted by other means, such as a phylo- rycea. Rafinesque (1822) suggested that September 2001] HERPETOLOGICA 277

the name Eurycea was mythological in or- C, 890: C, 903: C, 922: C, 934: C, 940: T, igin, although the etymology is not clear. 985: T, 1015: G, 1016: T, and 1018: T. Our inferred phylogenetic relationships Type species. -Eurycea chisholmensis. of the central Texas paedomorphic spring Content.-This clade is the "northern and cave salamanders are largely consis- group" of Chippindale et al. (2000), and tent with results based on allozyme and includes all the species of central Texas DNA data presented by Chippindale et al. Eurycea from north of the Colorado River (2000), and these relationships are now in Texas (currently, E. tonkawae, E. chish- well-enough understood that we name the olmensis, and E. naufragia). following major clades within this group. Etymology.-The name Septentriomol- Although all of these names are subgenera ge is formed from the Latin word septen- under ICZN rules, we use the informal trionalis, meaning "northern," and the old terms "section" and "division" to indicate generic name Molge (see the etymology of the relative hierarchy of the names for Typhlomnolge, above). Septentriomolge is their use under Linnaean nomenclature. masculine in gender. The species names of all the species in these groups can be treated identically un- Blepsimolge new clade (subgenus) der Linnaean nomenclature and phyloge- Definition.-The last common ancestor netic nomenclature (Cantino et al., 1999) of Eurycea neotenes Bishop and Wright by treating Eurycea as a genuis under the 1937, Eurycea nana Bishop 1941, and Eu- former system and as a recommended rycea troglodytes Baker 1957, and all of clade address for the species under the lat- the descendants of that common ancestor. ter system. This is one version of Method Diagnosis.-The following combination M of Cantino et al. (1999) for naming spe- of nucleotide states within the cies under a system of phylogenetic no- cytochrome b gene is menclature. diagnostic for Blepsimolge. The numbers refer to the positions within the Septentriomolge new clade (subgenus) aligned sequences referenced in Appendix I; position 1 corresponds Definition.-The last common ancestor to position 16268 of the complete of Eurycea tonkawae Chippindale, Price, Xenopus laevis mitochondrial genome Wiens, and Hillis 2000, Eurycea chishol- (GenBank accession number M10217). mensis Chippindale, Price, Wiens, and These character states are fixed within and Hillis 2000, and Eurycea naufragia Chip- unique to Blepsimolge in our pindale, Price, Wiens, and Hillis 2000, and analysis: 247: C, 514: G, 770: A, 805: C, all of the descendants of that common an- 866: T, 891: C, 1021: C, and 1024: C. cestor. Type species. -Eurycea nana. Diagnosis.-The following combination Content.-This clade contains E. lati- of nucleotide states within the cytochrome tans, E. nana, E. neotenes, E. sosorum, E. b gene is diagnostic for Septentriomolge. tridentifera, E. troglodytes, and E. ptero- The numbers refer to the positions within phila. the aligned sequences referenced in Ap- Etymology.-Blepsimolge is formed pendix I; position 1 corresponds to posi- from the Greek word blepsis (meaning tion 16268 of the complete Xenopus laevis "

1937, and all of the descendants of that 682: T, 692: A, 694: A, 700: A, 704: A, 706: common ancestor. A, 716: C, 742: A, 766: A, 856: A, 898: A, Diagnosis.-The following combination 902: A, 919: C, 929: T, 930: C, 931: A, 932: of nucleotide states within the cytochrome T, 941: A, 978: C, 980: C, 988: T, 991: T, b gene is diagnostic for Notiomolge. The and 1023:T. numbers refer to the positions within the Type species.-Eurycea tonkawae. aligned sequences referenced in Appendix Content. -This clade contains all the I; position 1 corresponds to position 16268 spring and cave Eurycea of the Edwards of the complete Xenopus laevis mitochon- Plateau of central Texas (see content of drial genome (GenBank accession number Blepsimolge, Typhlomolge, and Septen- M10217). These character states are fixed triomolge). within and unique to Notiomolge in our Etymology.-Paedomolge is formed analysis: 4: C, 22: C, 79: C, 250: C, 319: T, from the Greek prefix paedo- (from the 367: C, 403: C, 415: T, 427: T, 448: C, 545: Greek word paidos, meaning "child") and A, 556: A, 577: C, 616: T, 619: T, 784: C, the generic name Molge (see above). The 826: T, 863: T, 904: T, 926: A, 943: C, 946: name refers to the paedomorphic form of G, 973: C, 976: C, 982: A, and 1003: C. most of the species within this clade (a few Type species.-Eurycea neotenes. naturally transforming populations are Content.-This clade contains all the known within the E. troglodytes complex). species of paedomorphic Eurycea in cen- Paedomolge is masculine in gender. tral Texas that occur south of the Colorado River. It includes all the species in the BIOGEOGRAPHY clades Typhlomolge and Blepsimolge, and Figure 4 indicates that the oldest split is equivalent to the "southern group" of among the species of Paedomolge (the Chippindale et al. (2000). paedomorphic salamanders of the Ed- Etymology.-Notiomolge is formed wards Plateau) was between the clade from the Greek word notios (meaning north of the Colorado River (Septentriom- "southern") and the generic name Molge olge) and the clade south of the Colorado (see above), and is masculine in gender. River (Notionolge). This split presumably resulted from the action of the Colorado Paedomolge new clade (section) River as it cut down through the water- Definition. -The last common ancestor bearing strata of the Edwards Aquifer. The of Eurycea rathbuni (Stejneger 1896) and Edwards Plateau was first uplifted in the Eurycea tonkawae Chippindale, Price, late Cretaceous, but the erosion of the riv- Wiens, and Hillis 2000, and all of the de- er through the aquifer-bearing Edwards scendants of that common ancestor. Limestone formation was completed dur- Diagnosis.-The following combination ing a later round of uplifting in the Mio- of nucleotide states within the cytochrome cene (Abbott, 1975; Ragsdale, 1960; b gene is diagnostic for Paedomolge. The Woodruff and Abbott, 1986). Today, there numbers refer to the positions within the are believed to be few or no hydrological aligned sequences referenced in Appendix connections between the portions of the I; position 1 corresponds to position 16268 Edwards Aquifer north and south of the of the complete Xenopus laevis mitochon- Colorado River (Slade et al., 1986). The drial genome (GenBank accession number species of Septentriomolge differ from the M10217). These character states are fixed species of Notiomolge at an average of 180 within and unique to Paedomolge in our of 1026 positions (17.5%) of the cyto- analysis: 1:A, 10: C, 115: A, 118: T, 127: C, chrome b gene sequenced in this study 133: T, 161: A, 187: C, 190: T, 196: T, 199: (range: 167-194 differences, or 16.3- T, 244: A, 337: T, 341: T, 355: A, 400: A, 18.9%). Within Notiomolge, there is a pri- 430: C, 431: T, 457: A, 466: T, 481: G, 496: mary split between Typhlomolge and Blep- C, 536: T, 541: A, 544: T, 553: A, 562: C, simolge, which indicates a relatively an- 565: C, 566: A, 571: C, 601: C, 628: A, 634: cient speciation event between the subter- A, 658: T, 667: C, 668: C, 676: A, 680: A, ranean and the largely epigean species September 2001] HERPETOLOGICA 279

(with more recent colonization of subter- as a central principle in taxonomy: phylogenetic def- ranean habitats by E. latitans, E. tridenti- initions of taxon names. Systematic Zoology 39: 307-322. fera, and some populations of the other . 1992. Phylogenetic taxonomy. Annual Re- species of Blepsimolge). The average num- view of Ecology and Systematics 23:449-480. ber of nucleotide changes between the . 1994. Toward a phylogenetic system of bio- species of Typhlomolge and Blepsimolge is logical nomenclature. Trends in Ecology and Evo- 96 of 1026, or 9.4% (range: 84-102, or lution 9:27-31. FELSENSTEIN, J. 1985. Confidence limits on phylog- 8.2-10.0%). The level of sequence diver- enies: an approach using the bootstrap. Evolution gence between the two species of Ty- 39:783-791. phlomolge at Barton Springs and San Mar- INTERNATIONAL COMMISSION ON ZOOLOGICAL No- cos Springs (3.3% between E. waterlooen- MENCLATURE. 1999. International Code of Zoolog- sis and E. rathbuni) is similar to the level ical Nomenclature, 4th ed. International Trust for Zoological Nomenclature, London, U.K. of sequence divergence between the two LEVITON, A. E., R. H. GIBBS, JR., E. HEAL, AND C. species of Blepsimolge at these localities E. DAWSON. 1985. Standards in herpetology and (2.3% between E. nana and E. sosorum). ichthyology: part I. Standard symbolic codes for in- A third pair of subterranean/surface spe- stitutional resource collections in herpetology and cies exists in the Blanco River drainage (E. ichthyology. Copeia 1985:802-832. MITCHELL, R. W, AND J. R. REDDELL. 1965. Eury- robusta and E. pterophila). Therefore, the cea tridentifera, a new species of troglobitic sala- separation of these three segments of the mander from Texas and a reclassification of Ty- Edwards Aquifer may have resulted in the phlomolge rathbuni. Texas Journal of Science 23: co-speciation of one species of Typhlom- 343-362. olge and one species of MORITZ, C., C. J. SCHNEIDER, AND D. B. WAKE. Blepsimolge in 1992. Evolutionary relationships within the Ensa- each hydrologic area. tina eschscholtzii complex confirm the ring species interpretation. Systematic Biology 41:273-291. Acknowledgments.-We thank R. Hansen, who MURRAY, L. T. 1939. Annotated list of amphibians collectedsome of the type seriesof Euryceawater- and reptiles from the Chisos Mountains. Contri- looensisand provided information about the salaman- butions from Baylor University Museum 24:1-16. der surveys at Barton Springs; 0. Hernandez, who Palumbi, S. R. 1996. Nucelic acids II: the also assisted with polymerase collecting; D. Cannatellafor pro- chain reaction. Pp. 205-247. In D. M. viding access to specimens in the Texas Memorial Hillis, C. Moritz, and B. K. Mable (Eds.), Museum and providing Molecular System- advice on the manuscript; atics, 2nd ed. and A. Baldwin Sinauer, Sunderland, Massachusetts, who collected some of the data on U.S.A. cytochrome b sequences. POTTER, F. E., JR., AND S. S. SWEET. 1981. Generic boundaries in Texas cave salamanders, and a re- LITERATURE CITED description of Typhlomolge robusta (Amphibia: ABBOTT,P. L. 1975. On the hydrology of the Edwards Plethodontidae). Copeia 1981:64-75. Limestone, south-central Texas. Joumal of Hydrol- RAFINESQUE, C. S. 1822. On two new salamanders ogy 24:251-269. of Kentucky. Kentucky Gazette (new series) 1:3. BISHOP, S. C. 1941. Notes on salamanders with de- RAGSDALE, J. A. 1960. Petrology of Miocene Oakville scriptions of several new forms. Occasional Papers Formation, Texas Coastal Plain. M.A. Thesis, Uni- of the Museum of Zoology, University of Michigan versity of Texas, Austin, Texas, U.S.A. 451:1-21. SLADE, R. S., JR., M. E. DORSEY, AND S. L. STEWART. BISHOP, S. C., AND M. R. WRIGHT. 1937. A new ne- 1986. Hydrology and water quality of the Edwards otenic salamander from Texas. Proceedings of the Aquifer associated with Barton Springs in the Aus- Biological Society of Washington 50:141-143. tin area, Texas. Water Resource Investigation Re- CANTINO, P. D., H. N. BRYANT, K. DE QUEIROZ, M. port 86-4036, United States Geological Survey, J. DONOGHUE, T. ERIKSSON, D. M. HILLIS, AND Austin, Texas, U.S.A. M. S. Y. LEE. 1999. Species names in phylogenetic STEJNECER, L. 1896. Description of a new genus and nomenclature. Systematic Biology 48:790-807. species of blind tailed batrachian from the subter- CHIPPINDALE, P. T., A. H. PRICE, AND D. M. HILLIS. ranean waters of Texas. Proceedings of the United 1993. A new species of perennibranchiate salaman- States National Museum 18:619-621. der (Eurycea: Plethodontidae) from Austin, Texas. . 1907. Herpetology of Japan and adjacent ter- Herpetologica 49:248-259. ritory. United States National Museum Bulletin 58: CHIPPINDALE, P. T., A. H. PRICE, J. J. WIENS, AND 1-577. D. M. HILLIS. 2000. Phylogenetic relationships and SWOFFORD, D. L. 1998. PAUP*. Phylogenetic Anal- systematic revision of central Texas hemidactyliine ysis Using Parsimony (*and Other Methods). Ver- plethodontid salamanders. Herpetological Mono- sion 4. Sinauer Associates, Sunderland, Massachu- graphs 14:1-80. setts, U.S.A. DE QUEIROZ, K., AND J. GAUTHIER. 1990. Phylogeny SWOFFORD, D. L., G. J. OLSEN, P. J. WADDELL, AND 280 HERPETOLOGICA [Vol. 57, No. 3

D. M. HILLIS. 1996. Phylogenetic inference. Pp. AY014846): Hays Co., San Marcos Springs, 290 53' 407-514. In D. M. Hillis, C. Moritz, and B. K. 35" N, 970 55' 50" W (type locality); E. naufragia Mable (Eds.), Molecular Systematics, 2nd ed. Sin- (TNHC 51005, GenBank AY014843): Williamson auer, Sunderland, Massachusetts, U.S.A. Co., Cedar Breaks Hiking Trail Spring, 300 39' 36" WOODRUFF, C. M., JR., AND P. L. ABBOTT. 1986. N, 970 45' 02" W; E. neotenes: (TNHC 60313, Stream piracy and evolution of the Edwards Aqui- GenBank AY014850): Bexar Co., Helotes Creek fer along the Balcones Escarpment, central Texas. Spring, 29? 38' 15, N, 980 41' 40" W (type locality); Pp. 77-89. In P. L. Abbott and C. M. Woodruff, Jr. E. pterophila (TNHC 60316, GenBank AY014851): (Eds.), The Balcones Escarpment: Geology, Hy- Hays Co., Fern Bank Springs, 290 59' 00" N, 980 00' drology, Ecology and Social Development in Cen- 49" W (type locality); E. rathbuni: (TNHC 51174, tral Texas. Geological Survey of America, San Di- GenBank AY014844; TNHC 60314, GenBank ego, California, U.S.A. AY014845): Hays Co., Rattlesnake Cave, 290 54' 07" Accepted: 3 December 2000 N, 970 55' 17" W; E. sosorum (TNHC 50919, Associate Editor: Stephen Tilley GenBank AY014857): Travis Co., Barton Springs, 300 15' 49" N, 970 46' 14" W (type locality); E. tonkawae APPENDIX I (TNHC 60311, GenBank AY014842): Travis Co., Stillhouse Hollow Springs, 300 22' 28" N, 970 45' 55" Localities for Populations of Central Texas Eurycea W (type locality); E. trMdentifera (TNHC 51057, Examined for Cytochrome b Sequences GenBank AY014848): Comal Co., Honey Creek All localities are in Texas unless otherwise noted. Cave, 290 50' 50" N, 980 29' 30" W (type locality); E. Specimen numbers and GenBank accession numbers troglodytes (TNHC 60312, GenBank AY014853): are in parentheses following species names; museum Bandera Co., Sutherland Hollow Spring, 290 44' 58" acronyms follow Leviton et al. (1985). N, 990 25' 36" W; (TNHC 60318, GenBank Eurycea chisholmensis (TNHC 52770, GenBank AY014852): Gillespie Co., Trough Spring, 300 08' 36" AY014841): Bell Co., Salado Springs, 300 56' 37" N, N, 990 04' 40" W; E. waterlooensis (TNHC 60201, 970 32' 31" W (type locality); E. latitans (TNHC GenBank AY014855): Travis Co., Sunken Gardens 54536, GenBank AY014849): Kendall Co., Pfeiffer's Spring (type locality; holotype); (THNC 60203, Water Cave, 29? 45' 44" N, 980 39' 59" W (subter- GenBank AY014856): Travis Co., Barton Springs Pool ranean extension of type locality); E. m. multiplicata: (paratype), 300 15' 49" N, 970 46' 14" W; E. sp. (Ped- (TNHC 60315, GenBank AY014854): Polk Co., AR, ernales) (TNHC 60317, GenBank AY014847): Travis Band's Spring at Forest Service camp approximately Co., Hammett's Crossing Spring, 300 20' 28" N, 980 40 km SE of Mena; E. nana (UTA A-53663, GenBank 08' 14" W.