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For approximately four decades, scientists have known of the existence of several undescribed species of Siren in the southeastern United States Coastal Plain. One of these species, S. reticulata, was recently described, but a small, seepage-dwelling species has remained undescribed until now. To resolve outstanding questions concerning the phylogeny of Siren, we collected sequence and morphometric data from specimens across the range of Siren. We found S. lacertina and S. reticulata to represent strongly supported monophyletic groups, with S. reticulata having a sister relationship to all other Siren. Additionally, we found five distinct mtDNA lineages within what has been recognized as S. intermedia. Siren lacertina and type-locality S. intermedia (lineage A) are sister mtDNA lineages, whereas S. intermedia lineages B and C show a high level of mitogenomic divergence from type-locality S. intermedia. Analyses of two scnDNA loci revealed that S. lacertina is monophyletic but nested with low positional support in a clade including the three S. intermedia mtDNA lineages. Further study is needed to determine whether S. intermedia lineages A, B, and C represent distinct species or incompletely sorted lineages. We restrict the range of S. intermedia to the region from the Escambia and Perdido river drainages of Florida and Alabama eastward through Virginia (the combined ranges of lineages A, B, and C). We also elevate S. i. nettingi (lineage E) to species status and include the larger S. i. texana form in that taxon, generating a species that occurs from the Mobile Bay drainages westward through the Mississippi Basin and southwest into northeastern Mexico. Lastly, we describe a new miniature species, S. sphagnicola, that ranges from the Florida Parishes of Louisiana eastward to the westernmost tributary creeks of Choctawhatchee Bay in the western Florida panhandle.

Siren intermedia Barnes, 1826 (Figs. 1‒7, 9, 10, & 13) Common name. Intermediate Siren Neotype: UF Herp 190369 (Fig. 7A), adult female (gravid) from Wayne Co., Georgia, USA (31.50109°N, 81.91324°W, datum WGS84, elev. 13 m). Collected on 30 January 2020 by Dirk Stevenson, Arik Hartmann, and Matthew Fedler. Description of neotype: The neotype has 32 costal grooves and faint black spots on the dorsum extending from the head to the fourth costal groove behind the forelimbs. In life, it had a bluish gray venter and sides and a dark grayish brown dorsum. The slightly darker tail tip may indicate old regeneration. A broken chartreuse labial stripe runs from a few millimeters posterior of the nares to just anterior of the gills. Light yellow spots are present ventrolaterally on the head, often surrounding sensory pores. Sparse and more randomly placed small (Paratypes: UF Herp 188598, 189657 (Fig. 7B), 188604 (Fig. 7C), 188605 (Fig. 7D), 186989 (Fig. 7F), 190370 (Fig. 7E), 190371, 190374, 190375. Locality information for these specimens can be found via the Florida Museum of Natural History’s web database (http://specifyportal.flmnh.ufl.edu/herps/). Diagnosis. Siren intermedia has typical Siren characteristics: external gills with three fimbriate gill stalks, three associated gill slits, four toes on the forelimbs, lack of pelvic girdle and hindlimbs, and a thin, pigment-bearing mucus layer that overlies the keratinized skin. This species is best distinguished from other sympatric Siren lineages by costal groove count, which varies geographically. We restrict this species to the recovered S. intermedia lineages A, B and C. All S. intermedia lineages combined that we examined have 29‒33 costal grooves (Fig. 4). Lineage B has a more restricted costal groove range of 29 (n =12), 30 (n = 23), or 31 (n = 3) in areas of sympatry with S. sphagnicola., which has 31‒33 costal grooves in the East Bay, Yellow, Blackwater, and Escambia river drainages. Specimens of lineage B that are comparable in size to S. sphagnicola typically have yellow labial stripes, rostral patches, and ventrolateral flecking (Fig. 10). Siren intermedia lineages A (type clade) (Fig. 7) and C (Fig. 10) can be distinguished from sympatric Siren species by having fewer than 34 costal grooves. These two lineages exhibit hypervariability in pattern and coloration. Yellowish labial stripes and rostral patches may be present or absent. Numerous distinct black spots may be present, absent, or occur in patches on the dorsal and lateral surfaces of the head and body, and some individuals possess reticulated patterns (UF Herp 186989, 192033, and an unvouchered specimen from the same locality as 192033). These traits are also present in other Siren species and may be variable within populations of any of these species, emphasizing the need for accurate costal groove counts to distinguish from other species in the vicinity. Original description, first redescription, and comments. Le Conte (1828) provided the following description: “Its greatest length is twelve inches: colour uniform dusky, very slightly paler beneath, sometimes faintly speckled with darker above.” Barnes (1826) and Harlan (1827) announced that the species was going to be described and provided the same information when summarizing Le Conte’s forthcoming manuscript.According to Harlan (1827): “Colour resembling that of the Lacertina; branchiae resembling those of the Striata [i.e., Pseudobranchus striatus Le Conte]. Length about one foot.” We designated a neotype from near the type locality for the express purpose of clarifying the taxonomic status of a nominal taxon whose specimens (syntypes) were destroyed. Smith et al. (1975) clarified that the name should be attributed to Barnes (1826). Le Conte’s (1828) description provided additional traits that are generic among Siren and failed to identify any features that distinguish it from other Siren given our current understanding of the genus. Siren intermedia is extremely variable in both color and pattern, and many phenotypes overlap those of S. lacertina and S. nettingi. The original type locality was purportedly Le Conte’s Woodmanston Plantation, Riceboro, Georgia (Harper 1935). We chose the neotype locality, which is approximately 45 km SW of Woodmanston Plantation, because all sequenced specimens from the surrounding region and Altamaha River drainage belong to the same mtDNA lineage as our single Woodmanston Plantation specimen. The neotype locality is easily accessible and yielded many S. intermedia compared to other localities in the area. Additionally, the locality has stereotypical habitat for S. intermedia consisting of a cypress swamp with many small creeks and large accumulations of muck, leaf packs, and submerged Creeping Rush (Juncus repens [Michaux]). Noble and Marshall (1932) provided a redescription of S. intermedia but failed to state where the specimens they examined came from, and they likely included specimens from populations later split into the nettingi and texana subspecies of S. intermedia. This would explain their higher costal groove range for S. intermedia (up to 36 grooves). Additionally, they stated that the outer capsule of the egg was wider for S. lacertina than S. intermedia. This may ultimately be proven true by future studies, but their data are contradictory in light of the revised Siren taxonomy. Noble and Marshall (1932) compared specimens of what they considered to be S. intermedia and S. lacertina from the same locality (Maverick Co., Texas) to each other, as well as S. intermedia and S. lacertina from Oakley, Berkeley Co., South Carolina. A recent genetic study (LaFortune 2015) found that the Rio Grande drainage has only one genetic group of Siren; thus, Noble and Marshall (1932) and Flores-Villela and Brandon (1992) were comparing large and smaller individuals of the same species (now S. nettingi) using different names. Their findings indicate that different-sized individuals of the same species may have different-sized eggs, or they were comparing specimens with eggs at various stages of development. Size. The largest specimen we examined (UF Herp 186989) measured 191 mm SVL and 125 mm TaL (316 mm TL). Noble & Marshall (1932) reported a male S. intermedia (MCZ Herp A-140) from Georgetown, South Carolina, that measured 212 mm SVL and 347 mm TL. This animal is likely a member of S. intermedia lineage C. Goin (1957) provided 240 mm SVL and 381 mm TL for the maximum size of “ S. i. intermedia ” specimens he examined. However, he failed to provide the collecting locality or attribute the measurements to a vouchered specimen; thus, we are unable to assign it to a lineage. Because Goin assumed that only S. i. intermedia was present in the coastal drainages of Mississippi, Alabama, and the Florida Parishes of Louisiana, he may have attributed the size to a specimen that we now recognize as S. nettingi. Furthermore, his measurements closely match the size of the largest S. nettingi specimen we sequenced (LSUMZ 87289; 270 mm SVL, 408 mm TL) and the largest S. nettingi in the AUM collection (AUM 40435; 242 mm SVL, 365 mm TL). The smallest sexually mature female (UF Herp 190904) measured 75 mm SVL and 119 mm TL. Distribution. Our findings restrict S. intermedia to Atlantic and Gulf drainages from the vicinity of Chesapeake Bay south to central Florida and west throughout the Florida panhandle (Fig. 9). Specimens attributed to this species from the Mobile Bay drainage westward are likely either S. nettingi or S. sphagnicola. Common name. The first common name assigned to S. intermedia was Intermediate Siren (Gray 1831), and we suggest using this name instead of Lesser Siren because there are three larger sirens (S. lacertina, S. reticulata, S. nettingi) and three smaller sirens (S. sphagnicola, Pseudobranchus axanthus, P. striatus). This also aligns the epithet with the common name. Specimens examined. See Supplemental Table 1., Published as part of Fedler, Matthew T., Enge, Kevin M. & Moler, Paul E., 2023, Unraveling Siren (Caudata: Sirenidae) systematics and description of a small seepage specialist, pp. 351-378 in Zootaxa 5258 (4) on pages 369-374, DOI: 10.11646/zootaxa.5258.4.1, http://zenodo.org/record/7784322, {"references":["Barnes, D. H. (1826) An arrangement of the genera of batracian [sic] animals, with a description of the more remarkable species; including a monograph of the doubtful reptils [sic]. American Journal of Science and Arts, 11 (2), 268 - 297.","Le Conte, J. E. (1828) Description of a new species of Siren. Annals of the Lyceum of Natural History of New York, 2 (1), 133 - 134. https: // doi. org / 10.1111 / j. 1749 - 6632.1826. tb 00242. x","Harlan, R. (1827) Genera of North American Reptilia, and a synopsis of the species. Journal of the Academy of Natural Sciences of Philadelphia, 5, 317 - 372.","Smith, H. M., Smith, R. B. & Sawin, H. L. (1975) The authorship and date of publication of Siren intermedia (Amphibia: Caudata). Great Basin Naturalist, 35 (1), 100 - 102.","Harper, F. (1935) Records of amphibians in the southeastern states. The American Midland Naturalist, 16 (3), 275 - 310. https: // doi. org / 10.2307 / 2420030","Noble, G. K. & Marshall, B. C. (1932) The validity of Siren intermedia Le Conte, with observations on its life history. American Museum Novitates, 532, 1 - 17.","LaFortune, T. C. (2015) Species Identification and Habitat Assessment of the South Texas Siren. M. S. Thesis, University of Texas at Brownsville, Brownsville, Texas, 91 pp.","Flores-Villela, O. & Brandon, R. A. (1992) Siren lacertina (Amphibia: Caudata) in northeastern Mexico and southern Texas. Annals of the Carnegie Museum, 61, 289 - 291. https: // doi. org / 10.5962 / p. 226656","Goin, C. J. (1957) Description of a new salamander of the genus Siren from the Rio Grande. Herpetologica, 13 (1), 37 - 42. https: // doi. org / 10.2307 / 1439392","Gray, J. E. (1831) A synopsis of the species of the Class Reptilia. In: Griffith, E. & Pidgeon, E. (Ed.), The Animal Kingdom arranged in conformity with its organization, by the Baron Cuvier, member of the Institute of France, with additional descriptions of all the species hitherto named, and of many not before noticed. Volume the Ninth. The Class Reptilia arranged by the Baron Cuvier, with specific descriptions. Appendix. Whittaker Treacher, and Co. London, pp. 1 - 86 + 1 - 110 (Appendix), pls. 1 - 55."]}

Siren sphagnicola sp. nov. (Figs. 1‒6, 11–14) Common name. Seepage Siren Holotype. UF Herp 185209 (Fig. 11A), adult female from Junior Walton Pond in Okaloosa Co., Florida, USA (30.69270°N, 86.47250°W, datum WGS84, elev. 30 m) (Fig. 12 A & 12B). Collected on 18 January 2019 by Matthew Fedler, Paul Moler, and Pierson Hill. Paratypes. UF Herp 161516, 162498, 162568, 163271, 164240, 164241, 164242, 164243, 184285, 185195, 185200, 185201, 185208, 185209, 185214, 185215, 188766, 188767, 190036, 190037, 185205, 185216, 185197, 185198, 185210. Locality information for the various paratype localities is available via FLMNH’s UF Herpetology database (http://specifyportal.flmnh.ufl.edu/herps/). Description of holotype. The holotype has 32 costal grooves and faint black dorsal spots extending from the head to the forelimbs. It lacks approximately 3 mm of its tail tip. In life, it was mouse gray on its venter and sides with a grayish brown dorsum. Sensory pits on the head are well defined and beige in color. Measurements are 97 mm SVL, 49 mm TaL, 3.9 mm interorbital distance, 7.1 mm head width, 11.1 mm head length, 3.6 mm eye-snout distance, and 4.4 mm chest width. Diagnosis. Siren sphagnicola has typical Siren characteristics: external gills with three fimbriate gill stalks, three associated gill slits, four toes on the forelimbs, lack of pelvic girdle and hindlimbs, and a thin, pigment-bearing mucus layer that overlies the keratinized skin. A combination of traits distinguishes it from other members of the genus. It has 30‒33 costal grooves (Fig. 3) and a mouse gray base color with occasionally a light, grayish brown sheen on the dorsum (Fig. 11). Small juveniles in the post-macrocephalic larval stage, which is>2 months of age according to diagrams of growth/transition rates of S. nettingi provided by Noble & Marshall (1932), have the same gray coloration as adults (Fig. 11) and lack the orange, red, or yellow highlights present on other Siren juveniles of similar age (Fig. 13). A few adult specimens examined have small, well-defined black spotting on the head and occasionally on the dorsum (Fig. 11). Sensory pits on the head are more visible than those on heads of other Siren species and are typically ivory to beige colored, which may denote an absence of gray pigment rather than the presence of chromatophores (Fig. 11). This species lacks the yellow labial stripe present in young S. lacertina (Figs. 13B & 13F), S. intermedia (Figs. 13A, 13C, 13G, & 13I), and S. nettingi examined from the Mobile Bay drainage. Some juvenile S. intermedia in eastern populations also lack the light labial stripe. A few small juvenile S. sphagnicola have yellow spots or a short, broken stripe where a labial stripe is present in other species (Figs. 13E & 13H). Siren sphagnicola also lacks the post-cranial yellow or gold flecking found in many S. lacertina (Fig. 8), S. intermedia (Fig. 10), and S. nettingi. Gill stalk coloration is typically rosy pink to red in recently captured specimens but fades to grayish pink in captivity, likely due to changes in acidity or oxygenation of water. Intact tail tips are rounded, whereas partially regenerated tails (frequently observed) often taper to an abrupt point after the tail fin blade (Fig. 11). Regenerated portions of the tail seem to lack the density of gray pigment found in non-regenerated portions; thus, the regenerated portion is easily distinguished by its pinkish gray hue. Regenerated portions of the tail of other Siren species examined match the normal body coloration or have a brownish hue. Size. Siren sphagnicola is the smallest known species in the genus Siren. Additionally, all specimens examined are shorter than the maximum length given for both species of Pseudobranchus (Moler 2019b, c), making S. sphagnicola the smallest member of Sirenidae based on our current understanding. The largest specimen examined (AUM 27973) had an SVL of 126 mm, but it lacked a complete tail. The largest specimen with a complete tail (AUM 8960) had an SVL of 120 mm and a TaL of 76 mm (196 mm TL). We attributed these AUM specimens to S. sphagnicola based upon costal groove count, lack of labial striping and gold flecking found on sympatric S. nettingi and S. intermedia, and presence of beige-colored facial pores. Reproductive females have been found as small as 71 mm SVL (111 mm TL). When comparing measurement distributions of Siren lineages, S. sphagnicola was not distinct from any other single lineage in, at most, two of seven measurements (Table 4). Natural history and distribution. Based on our surveys in Florida, populations appear to be robust and widely distributed in suitable microhabitats in the Blackwater and Yellow river drainages and the western two-thirds of Eglin Air Force Base, including several streams that flow into the western side of Choctawhatchee Bay (Fig. 14). This suspected microhabitat specialist has been found in headwater seepage areas of steephead streams, mucky seeps farther downstream, muddy and/or densely vegetated seepage bogs, shallow-water depressions lined with dense sphagnum moss or filled with leaves along seepage-fed streamside terraces, and other types of shallow streams with mucky, detrital, or sandy bottoms (Enge 2005) (Fig. 12). In contrast, S. intermedia collected at localities near (S. sphagnicola were found in leaf packs not associated with seeps and adjacent to deeper water. Incised (gully-eroded) first- and second-order streams (Strahler 1964) lack the microhabitats used by S. sphagnicola (and many other salamander species), because accumulations of leaf litter and other detritus are constantly flushed from streams and scoured from surface pools by heavy rainfall events. Common, syntopic amphibian species are the Southern Cricket Frog (Acris gryllus [Le Conte]), Bronze Frog (Lithobates clamitans Latreille), Southern Two-lined Salamander (Eurycea cirrigera [Green]), and Southern Red Salamander (Pseudotriton ruber vioscai Bishop). Onetoed Amphiuma (Amphiuma pholeter Neill) and Two-toed Amphiuma (A. means Garden) may be present but are less abundant than the aforementioned species (Enge 2005). Deep, steephead ravine systems (Means 1981, 2000) and more shallow-gradient, seepage bogs in upland habitats near the Gulf of Mexico may have served as “evolutionary engines” during periods of elevated sea levels, producing the Florida Bog Frog (Lithobates okaloosae Moler, 1985), Bog Dwarf Salamander (Eurycea sphagnicola Wray, Means, & Steppan, 2017), and S. sphagnicola. A sea level rise of only 2‒5 m would have led to saltwater inundation of the mouths of these deep steephead valleys, thus isolating ancestral populations of freshwater species (Means 2000). We suspect the range of S. sphagnicola is similar to that of E. sphagnicola, which also inhabits the sphagnum-lined margins of streams and associated seepage habitats (Wray et al. 2017). Siren sphagnicola has a smaller geographic distribution than other Siren species. Most specimens have been found in the Blackwater,Yellow, and Escambia/Conecuh river drainages of Florida and Alabama (Fig. 14). Elsewhere, its range is poorly known, but we believe it is restricted to the environs of sandy, seepage-fed creeks in the lower Gulf Coastal Plain as far west as the Florida Parishes of Louisiana (Fig. 14). Locality information from outside Florida is entirely based on preserved AUM specimens and sequence data from a GenBank specimen that match both mtDNA and scnDNA markers. Few Siren museum vouchers with genetic material exist from Mississippi (42 total specimens via Vertnet search and only one with available tissue, which we sequenced) and the Florida Parishes of Louisiana (63 total via Vertnet search; one of two tissues requested yielded DNA), and we did not examine most museum specimens from this area that lacked tissue samples. Etymology and common name. The specific epithet is derived from Sphagnum, the generic name for sphagnum moss, and the Latin suffix -cola, meaning inhabitant or dweller. The species epithet is used as noun in apposition. This siren is frequently found in and under mats of Sphagnum in and along streams and the margins of other bodies of water. Because of its affinity for seepage-fed streams and wetlands, we suggest Seepage Siren as the common name. Specimens examined. See Supplemental Table 1.

Siren nettingi (Goin, 1942) (Figs. 1‒6 & 9) Common name. Western Siren Holotype. Carnegie Museum 7580. Adult female collected in May 1928 from Imboden, Lawrence Co., Arkansas, USA (Goin 1942). Paratypes. See Goin (1942). Diagnosis. Siren nettingi has typical Siren characteristics: external gills with three fimbriate gill stalks, three associated gill slits, four toes on the forelimbs, lack of pelvic girdle and hindlimbs, and a thin, pigment-bearing mucus layer that overlies the keratinized skin. Goin (1942) distinguished S. nettingi from S. intermedia by the presence of well-defined light spots on the sides and venter and also specifying that these were not the bar-like streaks found in S. lacertina. Additionally, Goin (1942, p. 212) stated that S. nettingi has “about two more costal grooves (usually 33 in intermedia, 35 in nettingi),” a value slightly overlapping but less than the average for S. lacertina. See comments below for possible reasons for variation in data. In areas of sympatry, the costal groove range of S. nettingi overlaps that of S. sphagnicola. Siren nettingi has 32‒34 costal grooves, with two outliers of 31 and 36 (Fig. 4). Goin (1942) gave a slightly higher range of 33‒37 costal grooves, but we infer that he included the axial groove or terminated counting grooves at a point posterior to our stopping point. Siren nettingi specimens similar in size to S. sphagnicola can be distinguished by the presence of a solid yellow labial stripe and rostral patch, whereas S. sphagnicola has, at most, several beige spots where the labial stripe occurs in other species. In addition, bodies of small S. nettingi often have a green or yellowish hue and gold flecking, both of with are lacking in S. sphagnicola. Comments. This species occupies a large geographic area, and we analyzed relatively few specimens, mainly from Alabama and Louisiana (Fig. 9). Our information may not represent the full extent of variation found in this species. Reinhard et al. (2013) provided photographs of larvae and mature adults of this species. After examining the holotype, we concluded that the well-defined, light spots on the venter referenced by Goin (1942) represent sensory pores rather than chromatophores. Chromatophores on the holotype are neither defined nor extensive in coverage. Regardless of this distinction, neither the distinct, light-colored sensory pores nor the yellow to yellow-green flecking of chromatophores is unique to S. nettingi. These pores are frequently obfuscated by the slime layer but become more visible when this is removed. This slime layer frequently sloughs off of poorly preserved or frozen specimens. Validity of the Rio Grande Siren (S. intermedia texana Goin, 1957) as a taxonomic unit distinct from S. nettingi has been questioned in recent decades. Our analyses suggest that S. nettingi and “texana” are either closely related sister taxa or ecomorphs of the same species adapted to habitats present in different regions. Further investigation of this topic is needed, but we treated “texana” as a distinct unit for morphological analyses. Furthermore, S. i. “texana” is no longer recognized by Highton et al. (2017), who accepted the erroneous designation by Flores-Villela and Brandon (1992) that the large siren from southern Texas and Mexico is S. lacertina (LaFortune 2015). Size. Siren nettingi has a reported maximum TL of 686 mm for the larger “texana” form found in southern Texas and Mexico, whereas the smaller form found in the rest of its range has a reported maximum TL of 502 mm (Martof 1973a). Flores-Villela and Brandon (1992) cited Goin (1957) for total lengths given by Martof (1973a and 1973b) and incorrectly reported the TL as the SVL for both the “texana” form of S. nettingi (then S. intermedia texana) and S. lacertina. Distribution. Based on our examination of museum specimens and genetic analyses, S. nettingi occurs from the Mobile Bay drainage westward, and native populations do not occur in any Florida drainage (Fig. 9). A single specimen that sequenced as S. nettingi was collected from Tates’s Hell State Forest, Franklin Co., Florida, but we suspect this specimen was translocated as live fish bait. Based on phenotypes and costal groove counts, Goin (1942) suggested that Florida Parishes of Louisiana represented the break between the then-recognized subspecies intermedia and nettingi. This boundary was later considered to be a hybridization zone that stretched into Mississippi (Boyd & Vickers 1963) and then to the Mobile Bay drainage (Caldwell & Howell 1966). We suspect part of this confusion resulted from examining S. sphagnicola and attributing them to S. i. intermedia because of their resemblance to grayish S. intermedia that can be found farther east. Furthermore, S. nettingi is currently thought to be the only Siren species that occurs from the Mississippi River west and south to Veracruz, Mexico. Common Name. We suggest the common name Western Siren. Except for the Mobile Bay drainage system, where S. reticulata is present, S. nettingi represents the largest or only siren (from the Mississippi River westward) present throughout its range; thus, the “Lesser” moniker is misleading. Specimens examined. See Supplemental Table 1., Published as part of Fedler, Matthew T., Enge, Kevin M. & Moler, Paul E., 2023, Unraveling Siren (Caudata: Sirenidae) systematics and description of a small seepage specialist, pp. 351-378 in Zootaxa 5258 (4) on pages 368-369, DOI: 10.11646/zootaxa.5258.4.1, http://zenodo.org/record/7784322, {"references":["Goin, C. J. (1942) Description of a new race of Siren intermedia Le Conte. Annals of the Carnegie Museum, 29, 211 - 217. https: // doi. org / 10.5962 / p. 215158","Reinhard, S., Voitel, S. and Kupfer, A. (2013) External fertilisation and paternal care in the paedomorphic salamander Siren intermedia Barnes, 1826 (Urodela: Sirenidae). Zoologischer Anzeiger-A Journal of Comparative Zoology, 253 (1), 1 - 5. https: // doi. org / 10.1016 / j. jcz. 2013.06.002","Goin, C. J. (1957) Description of a new salamander of the genus Siren from the Rio Grande. Herpetologica, 13 (1), 37 - 42. https: // doi. org / 10.2307 / 1439392","Highton, R., Bonett, R. M. & Jockusch, E. L. (2017) Caudata salamanders. In: Crother, B. I. (Ed.), Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico, with Comments Regarding Confidence in our Understanding. Society for the Study of Amphibians and Reptiles Herpetological Circular No. 43. 8 th Edition. Society for the Study of Amphibians and Reptiles, s. n., pp. 18 - 30.","Flores-Villela, O. & Brandon, R. A. (1992) Siren lacertina (Amphibia: Caudata) in northeastern Mexico and southern Texas. Annals of the Carnegie Museum, 61, 289 - 291. https: // doi. org / 10.5962 / p. 226656","LaFortune, T. C. (2015) Species Identification and Habitat Assessment of the South Texas Siren. M. S. Thesis, University of Texas at Brownsville, Brownsville, Texas, 91 pp.","Martof, B. S. (1973 a) Siren intermedia Le Conte. Lesser Siren. Catalogue of American Amphibians and Reptiles, 127, 1 - 3.","Martof, B. S. (1973 b) Siren lacertina Linnaeus. Greater Siren. Catalogue of American Amphibians and Reptiles, 128, 1 - 2.","Boyd, C. & Vickers, D. H. (1963) Distribution of some Mississippi amphibians and reptiles. Herpetologica, 19 (3), 202 - 205.","Caldwell, R. D. & Howell, W. M. (1966) Siren intermedia nettingi from Alabama. Herpetologica 22 (4), 310 - 311."]}

Roberto, Igor Joventino, Fedler, Matthew T., Hrbek, Tomas, Farias, Izeni P., Blackburn, David C. (2021): The Taxonomic Status of Florida Caiman: A Molecular Reappraisal. Journal of Herpetology 55 (3): 279-284, DOI: 10.1670/20-026, URL: http://dx.doi.org/10.1670/20-026