Gyrinophilus subterraneus Besharse & Holsinger, 1977
West Virginia Spring Salamander
|Species Description: Besharse, J. C., and J. R. Holsinger. 1977. Gyrinophilus subterraneus, a new troglobitic salamander from southern West Virginia. Copeia 1977: 624–634.|
© 2007 Danté B Fenolio (1 of 17)
DESCRIPTION: (A description of species morphology as if you had the amphibian in your hand, typically starting with the snout-vent length, then focusing from the head to the body and extremities)Gyrinophilus subterraneus is a troglobiotic salamander from West Virginia described from a mature female with a snout-vent length of 104 mm and a total length of 159 mm. The smallest observed transformed G. subterraneus has a snout-vent length of 96 mm. The head is longer than it is wide, with the widest part of the head being posterior to the eyes. The canthus rostralis are indistinct and the snout is almost twice as wide as it is long. The eyes have a diameter of 3 mm and are clearly visible. The forelimbs (15 mm) are shorter than the hind limbs (18.5 mm). The relative toe length is I < V < II < III < IV. There are 17 costal grooves between the axilla and groin, seven of which are between the limbs when appressed. There are 18 trunk vertebrae (Besharse and Holsinger 1977).
DIAGNOSIS: (How this species is differentiated from similar species)
Gyrinophilus subterraneus is closely related and sympatric to G. porphyriticus. Gyrinophilus subterraneus can be diagnosed based on its larger size, having a maximum larval snout-vent length of 112 mm (80 mm snout-vent length in G. porphyriticus); smaller eyes, with an eye diameter to snout-vent length ratio of 0.015 - 9.031 (compared to 0.026 - 0.031 in G. porphyritius); greater postorbital head width, with a head width to head length ratio of 0.80 - 1.03 (0.80 - 0.90 in G. porphyriticus); and the presence of two or three irregular rows of pale spots running laterally. Transformed G. subterraneus adult has smaller eyes with a ratio of eye diameter to snout-vent length of 0.023 - 0.031 (0.032 - 0.036 in G. porphyriticus), paler coloration, and indistinct canthus rostralis. Lastly, large larval and transformed adult G. subterraneus lose their sight, showing little or no optomotor response. Gyrinophilus porphyriticus larvae and adults consistently respond to visual stimuli (Besharse and Holsinger 1977).
COLORATION: (In life and/or in preservative)In life, Gyrinophilus subterraneus is a pale gray color with darker lateral and dorsal reticulations. The ventrum is peach-colored with some dark spots widely scattered under the jaw. In preservative, the gray color fades to become lighter, making the dark reticulations contrast more (Besharse and Holsinger 1977).
VARIATION: (if known)
Transformed G. subterraneus have a canthus rostralis, which is a characteristic of Gyrinophilus, but it may be indistinct due to lighter pigmentation (Besharse and Holsinger 1977).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: United States
U.S. state distribution from AmphibiaWeb's database: West Virginia
Life History, Abundance, Activity, and Special Behaviors
Visual ability degenerates before transformation, with large larvae and transformed adults giving little to no response to movements in the visual field (Besharse and Holsinger 1977).
In life, larvae have a brown-pink color, which is darker on the dorsal side than on the ventrum and sides. There is a light gray reticulated pattern that is darker on the dorsum, side, and limbs than on the tail. The ventrum has no reticulations and is light pink in color. The gills are bright red and the rami are lightly pigmented. The coloration in preservative is light gray, being slightly darker on the head and dorsum than on the side and tail. Light, peach-colored spots in two or three irregular rows are present on the sides of the body. Light gray reticulations cover the dorsum, and the ventrum is peach, without any reticulations. In both life and preservative, larger larvae with a snout-vent length over 80 mm also have pale yellow spots on the body in two or three irregular rows between the limbs and dorsally on the proximal area of the tail. These rows converge into one row of close-set spots on the lateral sides of the tail. Many of the spots have a central neuromast (Besharse and Holsinger 1977).
When transforming, the coloration of G. subterraneus is indistinguishable from the large larvae. At maturation, the dark reticulated pattern becomes more distinct while the lateral body spots become less so (Besharse and Holsinger 1977).
Gyrinophilus subterraneus larvae regularly have snout-vent lengths exceeding 100 mm, while those of G. porphyriticus rarely reach 80 mm, especially before metamorphosis. The smallest observed transformed G. subterraneus has a snout-vent length of 96 mm, while the minimum snout-vent length of transformed G. pophyriticus is 69 mm. This suggests that G. subterraneus metamorphosis occurs at a larger body size. Additionally, G. subterraneus larvae reach a wet body weight of over 40 g due to stores of body fat, while the maximum wet body weight for G. porphyriticus is under 20 g. Lastly, large larval and transformed adult G. subterraneus lose their sight, showing little or no optomotor response. Gyrinophilus porphyriticus larvae and adults consistently respond to visual stimuli (Besharse and Holsinger 1977).
Trends and Threats
Possible reasons for amphibian decline
General habitat alteration and loss
PHYLOGENETIC RELATIONSHIPS:Phylogenetic analyses have shown that G. subterraneus and G. porphyriticus are sister species. However the analyses also indicate that G. subterraneus is monophyletic and found within G. porphyriticus, making the latter paraphyletic and may indicate undescribed species diversity (Grant et al. 2022). According to δaδi analysis for evolutionary history, G. subterraneus underwent sympatric divergence from a larger G. porphyriticus population, with greater gene flow occurring asymmetrically from G. porphyriticus to G. subterraneus. Within the General Davis Cave, there is more nuclear DNA structure between G. subterraneous and G. porphyriticus than between G. porphyriticus populations that are separated by over 200 km. Additionally, the mtDNA between G. subterraneus and G. porphyriticus shows that the species diverged on a fine spatial scale. These genetic analyses show that there must be some reproductive barrier to gene flow between the species. Although F1 hybrids have been observed, no F2 or backcross hybrids have been found, also suggesting some form of reproductive isolation (Grant et al. 2022).
Gene flow is asymmetric, with greater gene flow occurring from G. porphyriticus to G. subterraneus. This may be due to the larger population of G. subterraneus in the cave, which would make female G. subterraneus individuals less likely to mate with male G. porphyriticus individuals due to chance. There may also be selection against hybrid offspring from G. subterraneus female and G. porphyriticus male crosses (Grant et al. 2022).
ETYMOLOGY (Origin or explanation of scientific name):The species epithet, "subterraneus," means “underground” and alludes to their cave-dwelling nature (Besharse and Holsinger 1977).
This species was featured as news of the week August 1, 2022:
Cave species are often highly endemic and can be especially vulnerable to habitat degradation within and surrounding the cave systems they inhabit. The West Virginia Spring Salamander (Gyrinophilus subterraneus) is only known from a single cave and though it is phenotypically distinct from the more widespread Spring Salamander species complex (Gyrinophilus porphyriticus), its evolutionary history and status as a unique species have been debated for decades. Grant et al. (2022) combine genomic and morphological data to demonstrate that G. subterraneus represent a distinct lineage, and that they occur in sympatry with G. porphyriticus within General Davis Cave. Surprisingly, the team also reports hybridization within the cave with evidence of partial reproductive isolation between the species. Collectively, the results provide strong support for continuing to recognize G. subterraenus as a distinct and unique species, and reveal a compelling study system for understanding how salamanders adapt to cave ecosystems. (Written by Rayna Bell)
Besharse, J.C., and Holsinger, J.R. (1977). "Gyrinophilus subterraneus, a New Troglobitic Salamander from Southern West Virginia." Copeia, 4, 624-634. [link]
Grant, E.H.C., Mulder, K.P., Brand, A.B., Chambers, D.B., Wynn, A.H., Capshaw, G., Niemiller, M.L., Phillips, J.G., Jacobs, J.F., Kuchta, S.R., and Bell, R.C. (2022). "Speciation with gene flow in a narrow endemic West Virginia cave salamander (Gyrinophilus subterraneus)." Conserv Genet, 23, 726-744. [link]
Originally submitted by: Madeline Ahn (2022-11-17)
Description by: Madeline Ahn (updated 2022-11-17)
Distribution by: Madeline Ahn (updated 2022-11-17)
Life history by: Madeline Ahn (updated 2022-11-17)
Larva by: Madeline Ahn (updated 2022-11-17)
Trends and threats by: Madeline Ahn (updated 2022-11-17)
Comments by: Madeline Ahn (updated 2022-11-17)
Edited by: Michelle S. Koo (2022-11-17)
Species Account Citation: AmphibiaWeb 2022 Gyrinophilus subterraneus: West Virginia Spring Salamander <https://amphibiaweb.org/species/5814> University of California, Berkeley, CA, USA. Accessed Dec 8, 2022.
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Citation: AmphibiaWeb. 2022. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 8 Dec 2022.
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