Desmognathus planiceps Newman, 1955
|Species Description: Tilley SG, Eriksen RL, Katz LA 2007 Systematics of dusky salamanders, Desmognathus (Caudata: Plethodontidae), in the mountain and Piedmont regions of virginia and North Carolina, USA. Zool J Linn Soc 152:115-130,|
© 2016 Will Lattea (1 of 7)
Desmognathus planiceps looks very similar to many species of the genus Desmognathus, including D. fuscus, D. monticola, and D. quadramaculatus but can be differentiated by D. planiceps having a flattened head, dorsal makings (see next paragraph), and tan spots on the venter. Desmognathus planiceps and D. fuscus were considered the same species and genetics is the best way to differentiate between the two. However, there are minor morphological differences between the two, including tooth morphology, in which D. planiceps has “broader” premaxillary teeth than D. fuscus, along with a “zone of distal crown expansion” closer to the tooth base than D. fuscus (Tilley et al. 2008). Desmognathus planiceps also has a similar morphology to D. marmoratus, mainly due to the flattened head. These species can be differentiated by the “inconspicuous inner naris, compressed tail, and absence of a premaxillary fontanelle of the latter” (Newman 1955).
Desmognathus planiceps is a brown (variation between shade of brown) colored salamander with a few distinct markings. The most noticeable marking is the dorsal marking. This marking is a black outlined, reddish-brown band that extend from the most dorsal region of the gular fold to the posterior section of the vent. Within the band are dark spots that line up along the mid-dorsal line. Other distinct markings are the yellow spots on the edge of the band above the forelimb junction with the body and the black spot on the center of the posterior section of a reddish-brown head. Dark-bordered light blotches line the tail region. There is brown and whitish-grey mottling on the sides of the body that stops abruptly on the outer edge of the belly. The sides of the tail have a row of light spots with dark borders. The ventral side of D. planiceps is white-tan and plain other than two sections. The first section, throat and gular fold region, is mottled with tan spots, while the other has the same mottling, except it occurs posterior to the hind limbs (Newman 1955).
There is evidence of sexual dimorphism with males having well-developed heads (Martof and Rose 1962). Males have a more pointed mental glad than females do. There is also variation in the ventral mottling with a select few individuals with full mottled ventral side (Newman 1955).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: United States
U.S. state distribution from AmphibiaWeb's database: Virginia
The species was collected in shallow, active streams that were cool in temperature with heavy shading (Newman 1995).
Life History, Abundance, Activity, and Special Behaviors
Reproduction is likely aquatic or semi-aquatic based on adult habitat preferences and a consistent lack of breeding migrations by Desmognathus species. Breeding migrations are unknown in this species, but the sister species D. fuscus does not make them (Bishop 1941). Breeding phenology has not been studied in D. planiceps, but adults of this sister species mate in fall and spring in adjacent areas of Virginia and deposit eggs between late June and mid-August (Organ 1961).
Newman (1955) reported collecting a single gravid female on 27 August 1955 with a snout-vent length of 47 mm that had 19 large eggs filled with yolk. The eggs measured 2 – 4 mm in diameter (Newman 1955).
The home range size of this species is unknown, but its occurrence is confirmed at only 9 localities in 5 Virginia counties (Tilley et al. 2008), suggesting that dispersal and movement rates may be low. Within this species’ range however, it is documented in two distinct physiographic regions, between which populations are polyphyletic (Blue Ridge Escarpment and Piedmont; Tilley et al. 2008), which suggest that movement across the physiographic boundaries between these two regions may be possible. Territories are not known, although Organ (1961) documented aggressive behavior in the sister species D. fuscus, relating this to sexual selection. Several other species of Desmognathus are known to maintain and defend territories, making this behavior likely to occur in D. planiceps.
Aestivation is unknown in this species, but it is restricted to shallow, cool, fast moving streams, where the temperature is unlikely to become sufficiently hot in summer to require aestivation. Individuals have been collected in every month May-August (Tilley et al. 2008), further suggesting that aestivation is unlikely. Seasonal migrations are unlikely, since no Desmognathus species are known to make seasonal migrations. However, Ashton (1975) observed individuals of D. fuscus moving into warmer microhabitats in winter, which is likely to be the case with this species as well, given the coldness of Virginia winters. Winter brumation has not been studied in this species, but all specimens of this species have been collected between May and August (Tilley et al. 2008).
Cannibalism by adults on both larvae and eggs has been reported in the sister species D. fuscus (Bishop 1941, Baldauf 1947, Wood and Clarke 1955, Jones 1986, Wilder 1913, Hamilton 1943), and may occur in D. planiceps as well.
Anti-predator mechanisms are unknown, although D. fuscus (the sister species of D. planiceps) has been reported to bite at snake predators and autotomize its tail when grabbed (Whiteman and Wissinger 1991). Caudal autotomy is common across the genus Desmognathus and almost certainly occurs in this species as well.
Trends and Threats
Changes in abundance and distribution for D. planiceps have not been described, but Tilley et al. (2008) reported successfully finding D. planiceps in the same areas Newman (1955) initially described it in.
Between 1962 and 2008, D. planiceps was classified as a subspecies of D. fuscus (Tilley et al. 2008). Although there is little literature on the threats to the D. planiceps, there is literature that expresses the cost of urbanization on D. fuscus, falling within the time frame above. Urbanization and road building are the two largest anthropogenic threats to D. fuscus (Orser and Shure 1972). Another problems affecting D. fuscus in areas adjacent to the range of D. planiceps is siltation. The problems affecting D. fuscus are likely to similarly affect D. planiceps. Efforts to quantify anthropogenic problems faced by D. planiceps may be essential for guaranteeing its continued persistence, especially given its high levels of endemism.
Possible reasons for amphibian decline
General habitat alteration and loss
The most closely related species to Desmognathus planiceps is Desmognathus fuscus. Between 1962 and 2008, D. planiceps was considered part of the D. fuscus species complex. However, maximum parsimony and maximum likelihood analysis of a fragment of Cyt b and cluster analysis of 22 allozyme loci showed that D. planiceps was genetically different from D. fuscus. Morphological differences were also found (Tilley et al. 2008). Other closely related species include Desmognathus carolinensis and Desmognathus monticola.
The genus name, Desmognathus, means “ligament jaw.” The specific epithet, planiceps, means “flat head.”
Desmognathus planiceps was discovered and described by Newman in 1955. In 1962, Martof and Rose placed D. planiceps within the D. fuscus species complex because of confusion involving the storage of the type specimens. This placement was reversed in 2008 by Tilley, Eriksen, and Katz (Mitchell 2013).
Desmognathus planiceps occurs syntopically with D. quadramaculatus, and overlaps in microhabitat preferences to a lesser extent with D. monticola. If a contact zone between D. planiceps and its sister species D. fuscus occurs, it is very abrupt. In addition to geographic segregation, D. fuscus is also less strictly aquatic than D. planiceps. Tilley et al. (2008) remarked that D. planiceps and D. fuscus “may represent yet another example of forms that have achieved a level of divergence sufficient to restrict gene flow, yet insufficient to permit sympatric coexistence.”
Ashton, R.E., Jr. (1975). ''A study of the movement, home range, and winter behavior of Desmognathus fuscus (Rafinesque).'' Journal of Herpetology, 9, 85-91.
Baldauf, R.J. (1947). ''Desmognathus f. fuscus eating eggs of its own species.'' Copeia, 1947, 66.
Bishop, S. C. (1941). ''The salamanders of New York.'' New York State Museum Bulletin, 324, 1-365.
Hamilton, W.J., Jr. (1943). ''Winter habits of the dusky salamander, in central New York.'' Herpetologica , 1943, 192.
Jones, R.L. (1986). ''Reproductive biology of Desmognathus fuscus and Desmognathus santeetlah in the Unicoi Mountains.'' Herpetologica , 42, 323–334.
Martlof, B. S., Rose, F. L. (1962). ''The taxonomic status of the Plethodontid salamander, Desmognathus planiceps.'' Copeia, 1962, 215-216.
Mitchell, J.C. (2013). ''Emmett Reid Dunn and the early history of herpetology in Virginia.'' Banisteria, 41, 27-39.
Newman W.B. (1955). ''Desmognathus planiceps, a new salamander from Virginia.'' Journal of the Washington Academy of Sciences, 45, 83–86.
Organ, J.A. (1961). ''Studies of the local distribution, life history, and population dynamics of the salamander genus Desmognathus in Virginia.'' Ecological Monographs , 31(2), 189–220.
Orser, P.N., Shure, D.J. (1972). ''Effects of urbanization on the salamander Desmognathus fuscus fuscus.'' Ecology, 53, 1148-1154.
Tilley, S.G., Eriksen, R.L., Katz, L.A. (2008). ''Systematics of dusky salamanders, Desmognathus (Caudata: Plethodontidae), in the mountain and Piedmont regions of Virginia and North Carolina, USA.'' Zoological Journal of the Linnean Society, 152, 115-130.
Whiteman, H.H., Wissinger, S.A. (1991). ''Differences in the antipredator behavior of three plethodontid salamanders to snake attack.'' Journal of Herpetology, 25, 352–355.
Wilder, I.W. (1913). ''The life history of Desmognathus fusca.'' Biological Bulletin , 24, 251-342.
Wood, J.T., Clarke, R.F. (1955). ''The dusky salamander: Oophagy in nesting sites.'' Herpetologica , 11, 150-151.
Originally submitted by: Jacob F. Brumley and Sky Button (first posted 2017-06-02)
Edited by: Ann T. Chang and Jarrett Johnson (2018-02-13)
Species Account Citation: AmphibiaWeb 2018 Desmognathus planiceps: Flat-headed Salamander <https://amphibiaweb.org/species/7014> University of California, Berkeley, CA, USA. Accessed Sep 25, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 25 Sep 2023.
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