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| Batrachoseps wakei Sweet & Jockusch, 2021 |
Abstract
Among western North American amphibian lineages, the plethodontid salamander genus Batrachoseps has undergone the most extensive radiation. Here we describe a new species in the genus from the vicinity of Point Arguello, central California. This lineage falls within the B. pacificus group, but it is differentiated from other species in the group by both molecular sequence data and morphology. It is geographically disjunct from its close relatives, with a tiny range in unlikely habitat along a narrow strip of the Pacific Coast, where it is entirely surrounded by B. nigriventris, a distant relative. Although intraspecific molecular variation is almost entirely absent, some population structure was detected across the 4 km extent of its range. Because of its tiny range and limited genetic variation, the impacts of any potential modifications to its known habitat should be evaluated to ensure the species' continued conservation.
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| Photos of Batrachoseps wakei. (A) Paratype (MVZ 293139, adult male, SVL = 60.4 mm) in life; (B) paratype of B. wakei (MVZ 293140, adult male, SVL = 63.0 mm) contrasted with B. nigriventris from Honda Canyon, Santa Barbara Co., California, in close parapatry with B. wakei; (C) EL J 1662. Photos A, B by Sam Sweet; photo C © Iñigo Martínez-Solano, used with permission. |
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Skull of an adult female Batrachoseps wakei (CCBER 32848, SVL = 53.0 mm); anterior ventral (top) and dorsal (bottom) views; bones, teeth, and cartilage (stippled) are shown. Scale bar = 2 mm. Dorsal view of the right front and hind foot of an adult male Batrachoseps wakei (CCBER 32847, SVL = 55.8 mm); cartilage is stippled. Scale bar = 2 mm. |
Batrachoseps wakei, new species
Suggested common name: Arguello Slender Salamander
Diagnosis.—The species is assigned to the genus Batrachoseps in having elongate genioglossus muscles attached to the midsection of the mandible, a large dorsal fontanelle in the skull, four toes on the hind feet, and genetic attributes that assign it to that genus. It is assigned to the subgenus Batrachoseps and differs from members of the subgenus Plethopsis (B. campi, B. robustus, and B. wrighti) in having fused premaxillary bones and more trunk vertebrae (21–22 vs. 17–19). Batrachoseps wakei is a large, long-bodied member (to 67.6 mm SVL, with 21–22 trunk vertebrae) of the B. pacificus group (Jockusch and Wake, 2002; Martínez-Solano et al., 2012), sharing with B. major and B. pacificus large body size, a dorsal pattern of longitudinally vermiculate tan markings on a medium brown ground color, few white iridophores either dorsally or ventrally, a tendency to show orange patches on the distal tail, and a pale venter (Fig. 2). Batrachoseps wakei differs from both species in having a smaller head, with the eyes protruding laterally beyond the margin of the upper jaw (Figs. 3–4), in having ca. 50% fewer melanophores on the throat and chest (Table 2), in often having extensive patches of orange pigment on the distal half of the tail (Fig. 2), in lacking melanophores in the peritoneal lining, and in genetic attributes described below. It further differs from B. pacificus in having a longer tail. It further differs from B. major in having proportionally longer limbs, larger feet, and a shorter tail (Fig. 4). Batrachoseps wakei has a proportionally smaller head and longer tail than B. m. aridus, a morphologically distinctive lineage variably treated as a subspecies of B. major (Wake and Jockusch, 2000) or as a species (e.g., AmphibiaWeb, 2020), the ventral trunk is pale, and the dorsal pattern is of pale longitudinal vermiculations rather than a dense suffusion of gold and silver iridophores as seen in B. (m.) aridus.
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Etymology.—The species is named in honor of David Burton Wake, Professor of the Graduate School and emeritus Director of the Museum of Vertebrate Zoology at the University of California, Berkeley, in recognition of his immense contributions to the knowledge of California salamanders, as well as his broader roles in both amphibian conservation and evolutionary studies in western North America. David Wake has set an example of scholarship and integrity that has inspired his colleagues and his many graduate students (of whom we are two) by his insightful and never routine work on the evolution of salamanders, spanning the range of morphology, systematics, ecology, molecular genetics, and phylogeography. The complexity of the genus Batrachoseps has been progressively revealed by his embrace of the most current analytical techniques, and this is one of a minority of the 22 species in the genus that he has not had a hand in discovering or naming. As Museum of Vertebrate Zoology Director from 1971–1998, David Wake nurtured the museum's focus on discovering the diversity and evolutionary history of western North American tetra-pods. He also played a critical early role in focusing attention on the emerging declining amphibian crisis (e.g., Blaustein and Wake, 1990) and, as a founder of AmphibiaWeb, in promoting a collaborative vision for the amphibian research community and making high quality information about amphibians easily accessible to all.
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| Distribution and relationships of the B. pacificus group. (A) Colored polygons show the ranges of the seven species currently recognized in B. pacificus (based on IUCN range polygons), and black dots show the locations of molecular samples included in this study; brown polygon shows range of B. nigriventris. Arrow and purple circle indicate the locality of the species described here. Map tiles by Stamen Design, under a CC BY 3.0 license. Map data by OpenStreetMap under ODbL. (B) Species tree for the B. pacificus group and selected outgroups inferred from coalescent analysis of seven nuclear and one mitochondrial marker. Support values are ASTRAL-III's local posterior probabilities; branch lengths are in coalescent units. See Data Accessibility for tree file. |
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| Habitat of Batrachoseps wakei. (A) Type locality at Point Arguello, California, USA; (B) northernmost locality at Honda Point, California, USA. Photographs © Ivan Parr, used with permission. |
Samuel S. Sweet and Elizabeth L. Jockusch. 2021. A New Relict Species of Slender Salamander (Plethodontidae: Batrachoseps) with a Tiny Range from Point Arguello, California. Ichthyology & Herpetology, 109(3); 836-850. DOI:10.1643/h2020027
