A new, narrowly endemic species of swamp-dwelling dusky salamander (Plethodontidae: Desmognathus) from the Gulf Coastal Plain of Mississippi and Alabama
Author
Pyron, R. Alexander
Division of Amphibians and Reptiles, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560.
Author
O’Connell, Kyle A.
Division of Amphibians and Reptiles, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560. & Deloitte Consulting LLP, Biomedical Data Science Lab, Arlington, VA;
Author
Lamb, Jennifer Y.
Department of Biology, St. Cloud State University, 720 4 th Avenue South, St. Cloud, MN 56301 - 4498.
Author
Beamer, David A.
Department of Natural Sciences, Nash Community College, Rocky Mount, NC 27804.
text
Zootaxa
2022
2022-05-03
5133
1
53
82
journal article
305644
10.11646/zootaxa.5133.1.3
5c481a49-42fa-40cc-926d-265d3ae52af4
1175-5326
6521455
9EEE49B5-5B83-41F0-A2A6-32FF1D1EE2C4
Desmognathus pascagoula
sp. nov.
D. auriculatus
(
Valentine 1963
; populations from
Jackson Co.
,
Mississippi
)
D. valentinei
(
Means
et al.
2017
; populations from
Jackson Co.
,
Mississippi
and
Mobile
and
Baldwin Co.
,
Alabama
)
Holotype
:
USNM 596040
(field tag RAP1106;
Figs. 13
,
14
), collected by
RAP
on
11 December 2019
at 1410h in a small seep feeding into
Ward Bayou
at
Ward Bayou
WMA,
Jackson Co.
,
Mississippi
(30.56, -88.62;
3m
ASL).
Paratypes
:
MMNS 19623
(field tag JYL78;
Figs. 15
,
16
), collected by
JYL
on
23 March 2013
at the type locality (30.56, -88.62,
3m
ASL).
AUM 45885
(field tag RAP1107;
Fig. 17
), collected by
RAP
on
10 December 2019
at ~1200h, and
MNHN-RA 2021.0149
(field tag RAP1479), collected by
DAB
and
RAP
on
28 November 2020
at ~1000h, in a branch of
Franklin Creek
,
Mobile Co.
,
Alabama
(30.45, -88.32;
15m
ASL).
ANSP 38808
,
AUM 45896–7
, and
MCZ A-153479
(field tags RAP1480–3), collected by
DAB
and
RAP
on
28 November 2020
at ~1200h and
USNM 596044
(field tag RAP 2218) collected by
RAP
,
DAB
, and
NA
on
4 January 2022
at ~1700h in a branch of
Franklin Creek
at Number 12 Swamp,
Mobile Co.
,
Alabama
(30.45, -88.35,
9m
ASL).
MMNS 19997
(field tag RAP1558), collected by
RAP
and
DAB
on
12 December 2020
at ~1600h in the floodplain of
Cowart Branch
,
Greene Co.
,
Mississippi
(31.00, -88.78,
14m
ASL).
ANSP 38810
,
BMNH 2021.7559
, and
AMNH 193779
(field tags RAP1559–61) collected by
RAP
and
DAB
on
12 December 2020
at ~1900h and
USNM 596041–3
(field tags RAP2208–10) collected by
RAP
,
DAB
, and
NA
on
3 January 2022
at ~1100h in a tributary seep of
Sweetwater Creek
,
Perry Co.
,
Mississippi
(30.91, -88.86,
43m
ASL)
.
Etymology:
The species name is a noun in apposition, referring to the Pascagoula River drainage that comprises much of their known range. “Pascagoula” is derived from a Chahta Yakni (Choctaw) or Mobilian Jargon term meaning “bread people” or “bread nation” (
Gallatin, 1836
;
Gannett, 1905
;
Iti Fabvssa, 2015
). The Pascagoula tribe, after which the river is named, was one of the Indigenous peoples that lived in what is now south
Mississippi
prior to European colonization. The region continues to be home to the Chahta Yakni and the Biloxi.
Suggested Common Name:
Pascagoula Dusky Salamander.
Diagnosis:
Desmognathus pascagoula
can be distinguished from all other similar or related species by the following combination of characters: adult body size moderate (mean
47 mm
SVL, range =
32–56 mm
); torso elongated (AG 58% of SVL, range 56–61%) and slender (CW = 13 [11–14]%); head narrow (HW = 15 [12– 16]%); eyes and nostrils closely set (IC and IN = 6 [5–7] % and 4 [4–5]%); snout rounded off giving a blunted or brachycephalic appearance (ES = 5 [4–6]%); tail fin-like and long (TL = 80% of SVL, 62–101%); dorsal color pattern distinct but irregular; ventrolateral (3
rd
) row of “portholes” on the body and lateral (2
nd
) row tail of “portholes” on tail usually visible but jagged or irregular, dorsolateral row (1
st
row) typically indistinct or faded; postocular stripe distinct and bright, typically orange or yellowish orange.
Description:
All but one known specimen appears to be adult or subadult; nothing is known of egg or juvenile morphology, habits, or behavior. A potential larval specimen with gills (DAB16336;
18 mm
SVL) was captured at the Sweetwater Creek site on
12 December 2020
and bears little obvious distinctiveness from the larvae of
Desmognathus valentinei
(see
Means
et al.
2017
). Several larvae were observed at the Chickasaw Creek site, all of which bore superficial resemblance to those of
D. valentinei
.
Mature
D. pascagoula
are moderately large dusky salamanders, with a tail that is thick, girthy, long, and compressed laterally into a fin- or blade-like shape towards the tip. Adults generally have a ground color of dark brown/black or tan/beige, a distinct dorsal color pattern separated from a lighter dorsoventral coloration, and a ventral coloration similar to the sides, typically with melanophores in the stellate condition (
Fig. 16
). The dorsal color pattern is typically a solid brown or reddish-brown stripe, edged with roughly 8–10 indistinct chevrons on either side, likely representing the remnants of larval spots. Other
Desmognathus
including
D. valentinei
can have dorsal color patterns including a reddish-brown stripe, but with more rounded or scalloped edges. In
D. pascagoula
these edges are more angular in nature, hence our description as “chevrons.” The dorsoventral surfaces are noticeably lighter, with an abrupt transition from darker dorsally to lighter laterally and ventrally creating a “two-toned” effect (
Figs. 15–18
). The distinct dorsal stripe is often visible onto the tail. The lateral surfaces of the trunk and tail usually have the round, whitish “portholes” characteristic of many swamp-dwelling
Desmognathus
species.
The dorsolateral (1
st
) row on the body is usually small and indistinct, and the lateral (2
nd
) row on the body may be incomplete or less pronounced than is the ventrolateral (3
rd
) row. When “portholes” are present, they often have jagged, uneven edges rather than being circular and smooth-edged. In the
holotype
, which is lighter and more tan or beige colored overall, they are barely noticeable in any of the three rows. The head is indistinct from the neck, and the snout is blunt or brachycephalic, rounded off in front. The dorsal stripe in the nuchal region occasionally has lighter or more distinct margins, giving the slight appearance of a paired stripe on the neck. The postocular stripe characteristic of
Desmognathus
is bright orange or yellowish orange in all known specimens.
Comparison:
Only two species are likely to be confused with
Desmognathus pascagoula
:
D. conanti
C (
Kozak
et al.
, 2005
;
Fig. 11
); and
D. valentinei
(
Figs. 12
,
19–22
), the sister species of
D. pascagoula
with which it has been conflated in print (
Beamer and Lamb, 2020
;
Means
et al.
2017
;
Pyron
et al.
, 2020
,
2022a
). The swamp-dwelling
D. valentinei
replaces
D. pascagoula
to the north and west and can be distinguished based on several characteristics. Adult
D. valentinei
get substantially larger than
D. pascagoula
(maximum
62 mm
SVL vs. 56). Large adults of
D. valentinei
typically lack bold, distinct dorsal color patterns on the body (
Means
et al.
, 2017
), unlike larger
D. pascagoula
(
Fig. 15
). Juvenile
D. valentinei
exhibit bold, reddish orange dorsal color patterns with clearly scalloped edges (
Means
et al.
, 2017
). This
type
of pattern is lacking in juvenile or smaller
D. pascagoula
(
Figs. 13
,
14
,
18
; see
Means
et al.
, 2017
). Round “portholes” on the lateral surfaces of the trunk and tail form up to three visible rows that are usually obvious, distinct, and occasionally reddish in
D. valentinei
,
but less distinct or jagged and always whitish in
D. pascagoula
(
Figs. 13–18
).
Ravine and stream-dwelling populations of
Desmognathus conanti
representing the C lineage (see
Beamer and Lamb, 2020
) are sympatric with
D. pascagoula
at the
type
locality, from which they can be distinguished based on several characteristics. The dorsal color pattern of
D. conanti
C is typically a more distinct paired row of square or round blotches originating as larval dorsal spots, while the dorsal stripe of
D. pascagoula
is indistinct or with angular, “chevron” edges. The tail of
D. conanti
C is more slender and less compressed than
D. pascagoula
,
which has a heavily keeled fin- or blade-like tail. The dorsolateral surfaces of
D. conanti
C are typically heavily pigmented with irregular, light-colored flecking or spotting of various sizes, often extending onto the lateral surfaces of the tail, while
D. pascagoula
has lighter colored dorsoventral surfaces usually lacking any obvious patterning. An exception are the light-colored “portholes” that are usually indistinguishable from the wash of light-colored flecking in
D. conanti
C, but usually visible in
D. pascagoula
. The postocular stripe in
D. conanti
C is usually indistinct and typically white in color, while in
D. pascagoula
it is typically bright orange or orangish yellow. Finally, the snout of
D. conanti
C is typically pointed and somewhat spatulate in a “duck-bill” morphology (
Fig. 11
), while
D. pascagoula
is more rounded, with a blunt or brachycephalic appearance (
Figs. 13–18
).
FIGURE 13.
The holotype (USNM 596040/RAP1106) of
Desmognathus pascagoula
in life on isolated (a) and naturalistic (b) backgrounds. Note the relative lack of distinct “portholes” in the dorsolateral and lateral rows on the body and tail, and the bright orange postocular stripe. The ventrolateral row of “portholes” is partially visible on the body.
FIGURE 14.
The holotype (USNM 596040/RAP1106) of
Desmognathus pascagoula
in preservative in dorsal (a) and ventral (b) views. Tick marks on ruler are in mm.
Variation:
Like
many
Desmognathus
species
,
D. pascagoula
exhibits substantial variation in color pattern, seemingly (at least in part) as a local adaptive response to their primary substrate (see
Grobman, 1950
).
Most
of the
Grand Bay
specimens and the
Ward Bayou
paratype
are dark colored and were found in leafy pools of dark-colored muck. Some of the
Grand Bay
specimens were lighter in color, but still with a dark gray ground color (
Fig. 18
). In contrast, the
holotype
was captured in light-gray silty muck (
Fig. 5
) and is accordingly much lighter-colored (
Fig. 13
). This type of substrate-specific variation has previously been noted in Coastal Plain
Desmognathus
by numerous authors (
Means
et al.
, 2017
;
Valentine, 1963
). We did not observe any noticeable metachrosis in numerous specimens captured alive and held for>24 hours.
Reproduction:
Nothing is known of the reproduction of this species, as no populations have been studied in detail, to our knowledge.
Dimorphism:
Little is known about sexual variation in this species. As with most
Desmognathus
,
large adult males seem to exhibit peramorphic jaw musculature as in their sister species
D. valentinei
(
Means
et al.
, 2017
)
. Other characteristics related to peramorphic cranial ontogeny may also differ sexually (see
Means 1974
).
Habitat:
All known specimens have been found in or near a similar
type
of microhabitat, comprising seeps or pools of leafy muck in the floodplains or swampy lowlands adjacent to larger creeks or rivers. At the three Mobile Co. sites, most specimens were found in the leaf/water/muck matrix and were uncovered by raking through this habitat, while a few were in the muck underneath debris dams of accumulated leaves and sticks. Both Ward Bayou specimens were found under partially submerged logs in a seep consisting primarily of leafy muck (similar to the Grand Bay site) and some flowing water. The Cowart Branch specimens were found under logs in lowland blackwater cypress swamp habitat, while the Sweetwater Creek specimens were primarily in sphagnum mats at the base of ravine seeps. In contrast to
Desmognathus auriculatus
A and
D. valentinei
,
which are often found to be more active and closer to the surface,
D. pascagoula
appears, from our limited sample, to be more secretive and prefer more concealed or obscured microhabitats, deep under logs or in the aquatic sediment and vegetation layers.
Referred Material:
Only a few specimens referred to
Desmognathus auriculatus
are known from
Jackson Co.
,
Mississippi
, potentially representing
D. pascagoula
or
D. valentinei
. A collection from north of
Cumbest Bluff
dates to 1954 (
CM 130968
-70), and one from 1957 (FMNH 193516, 193811) bears only the locality “Jackson Co.” A MMNS series collected by
L.H. Kendall
in 1963 includes individuals from
Ocean Springs
(MMNS 11395),
Moss Point
(MMNS 11432–4),
Kreole
(MMNS 11598–9, 11905–6), and
Escatawpa
(MMNS 11847–8), and a single specimen (MMNS 16064) was reported in 2007 from
Ward Bayou
WMA.
We
did not examine these specimens; it is thus possible that some represent
D. conanti
,
with which
D. auriculatus
has been confused in the area (see
Beamer and Lamb, 2008
;
Valentine 1963
).
FIGURE 15.
The Ward Bayou paratype (MMNS 19623/JYL78) of
Desmognathus pascagoula
in life. Note distinct dorsal color pattern, the irregular lateral “portholes” on the trunk and tail, and the larger ventrolateral “portholes.”
We examined five historical collections possibly referable to
Desmognathus pascagoula
.
First, USNM 51142–51 dates to
19 Feb 1914
from
Biloxi
,
Harrison Co.
,
Mississippi
.
These
specimens resemble
D. valentinei
,
populations of which exist in that county confirmed by DNA sequencing (
Means
et al.
, 2017
), and the locality is outside the
Pascagoula
drainage, suggesting that they are likely indeed
D. valentinei
.
Nevertheless
, a contact zone between the
D. pascagoula
and
D. valentinei
likely occurs somewhere in this region.
Second
, USNM 57226, 57228, 57232–36, and 51142–51 lack specific localities, but 57226 dates to
Sep 1894
from
Baldwin Co.
,
Alabama
; 57228 dates to 1909 from
Mobile Co.
,
Alabama
; and 57232–36 dates to
28 May 1910
from
Mobile Co.
,
Alabama
.
None
are particularly well-preserved, but all have a distinct
auriculatus-
type
morphology, including a blunt or brachycephalic snout, slender, elongated trunk, white lateral portholes of varying degrees of distinctiveness, and long, keeled tails.
We
tentatively conclude that these are
D. pascagoula
based on locality and appearance.
Third
, a lot of
four specimens
originally catalogued under MCZ A-2783 as
Desmognathus
“
cf.
auriculatus
”
were collected by
Julius Hurter Sr.
from
Mobile Co.
,
Alabama
in
February 1911
.
Of
these, three were later re-catalogued as MCZ A-4745–7, of which A-4745 is a
Plethodon glutinosus
complex.
The
remainder are
Desmognathus
,
of which A-4746 is
D. conanti
C, collected on
13 February 1911
, and A-2783 & A-4747 appear to be
D. pascagoula
,
collected on 5 &
10 February 1911
, respectively.
We
again base this on a blunt or brachycephalic snout, slender, elongated trunk, white lateral portholes of varying degrees of distinctiveness, and long, keeled tails.
No
additional locality data are contained in the MCZ catalogue.
FIGURE 16.
Ventral view of the Ward Bayou paratype (MMNS 19623/JYL78) of
Desmognathus pascagoula
in life. Note the darkened “stellate” condition of the ventral melanophores, as in nearby populations of
D. valentinei
(see
Means
et al.
2017
). The jagged but prominent ventrolateral line of portholes is clearly visible here on the body, as is the lateral row of “portholes” on the tail.
Fourth, the University of South
Alabama
museum has an extensive collection of
Desmognathus
from Mobile Co. Based on photographs of some specimens provided by D. Bruce Means, most appeared to represent
D. conanti
C. However
, two collections may represent
D. pascagoula
.
The first is “U. of S.A. #966–7” from “
2 mi.
N.W. of Semmes along N side of G.M.&O. Railroad” collected
26 November 1968
. The second is “U. of S.A. #1517” from “2 ½ air miles SW of Semmes on Wolff Rd. at small stream” collected
18 November 1969
. These specimens are faded and poorly preserved, but resemble
D. pascagoula
in having slender trunks, long laterally compressed tails, and relatively short toes. These localities are ~
15km
WSW of the Chickasaw Creek site and occur near what is or would have been suitable lowland swamp habitat. It seems likely that
D. pascagoula
occurs or occurred in this region. We did not examine other specimens in person; more
D. pascagoula
may be present in this collection.
FIGURE 17.
A Grand Bay paratype (AUM 45885/RAP1107) of
Desmognathus pascagoula
in life on isolated (a) and naturalistic (b) backgrounds. Note the bright orange postocular stripe shared by all adult specimens, and the resemblance to the Ward Bayou paratype in terms of the distinct coloration on the dorsal surface of the tail, dark overall coloration, and visibility of the ventrolateral portholes on the body and lateral row of “portholes” on the tail.
FIGURE 18.
Additional specimen (DAB11479) of
Desmognathus pascagoula
from the Grand Bay locality, showing variation in color pattern. Note overall lighter coloration compared to the paratypes, though still exhibiting a bright orange postocular stripe, relatively indistinct dorsolateral “portholes,” two-toned lateral coloration and jagged ventrolateral row of “portholes,” reddish-orange stripe on the dorsal surface of the tail, and increased prominence of lateral “portholes” on the tail, which is fat, keeled, and blade-like towards the tip (partially regenerated).
Fifth, a specimen of exceptional interest is AUM 10543 (
Fig. 23
), collected
30 March 1968
by
J. Byford
“
5 miles
SW Tensaw
, approx
2 miles
East
of bend in
Alabama
River, on Ft Pierce Hunting Club.” This locality is a significant distance from the other historical
Alabama
populations of
Desmognathus auriculatus
which occurred west of the
Apalachicola River
in the
Florida
panhandle and adjacent southeastern
Alabama
(
Means, 1999
). The specimen was considered to represent
D. auriculatus
by
Graham
et al.
(2010)
and
D. valentinei
by
Means
et al.
(2017
: their
Fig. 5
). Due to preservation differences, we did not take measurements to include in our linear morphometric analyses. Nevertheless, several features suggest that this specimen represents
D. pascagoula
.
These are an elongated head and relatively blunt or brachycephalic snout; relatively closely set eyes and nostrils; a relatively slender, elongated trunk; a distinct orbito-labial stripe (faded in preservative, but of an apparently bright color in life); a distinct dorsal color pattern; noticeable lateral “portholes” on the trunk and lateral side of tail; ventral melanophores in the “stellate” condition; and a heavily keeled, “fin-like” or “blade-like” tail. Of these, we consider the distinctiveness of the dorsal color pattern and indistinctiveness of the lateral “portholes” as the strongest evidence for conspecificity with
D. pascagoula
.
Finally, we refer AUM 45536–7 (field tags RAP2222 & 2223) and USNM 596045–6 (field tags RAP 2221 & 2224), collected by RAP, DAB, and NA on
5 January 2022
at ~1200h in a ravine tributary of
Chickasaw Creek
,
Mobile Co.
,
Alabama
(30.78, -88.09,
6m
ASL) to this species.
Given
the overall extreme level of mitochondrial divergence in this group compared to most congeners, the presence of higher levels of infraspecific divergence within other similar candidate species (e.g.,
D. auriculatus
A = 6.8%,
D. auriculatus
B/C = 8.4%), the apparent lack of morphological differentiation, and their spatial proximity (~
42km
between the
Chickasaw Creek
and
Franklin Creek
sites), we continue to treat the
Mobile
drainage population as
D. pascagoula
, representing a distinct phylogeographic lineage
sensu
Pyron
et al.
(2022a)
.
There
is a clear need to sample additional individuals from the
Mobile-Tensaw River
delta in
Baldwin
and
Mobile Co.
and include them in phylogenomic analyses.
FIGURE 19.
Small specimen (MMNS 19990/RAP1109) of
Desmognathus valentinei
from Thompson Creek, Wayne Co., Mississippi, showing typical juvenile form and color of “pale
auriculatus
”
sensu
Valentine (1963)
, notably a blunt snout; indistinct postocular stripe; indistinct dorsal color pattern; distinct ventrolateral and lateral “portholes” on the trunk and tail; and distinctly keeled, “fin-like” or “blade-like” tail (partially regrown).
FIGURE 20.
Large adult specimen (MMNS 19991/RAP1110) of
Desmognathus valentinei
from Thompson Creek, Wayne Co., Mississippi, showing typical adult coloration of “pale
auriculatus
”
sensu
Valentine (1963)
. Note overall distinctiveness in body form and coloration from
D. pascagoula
,
including muted coloration of the postocular stripe, girth of the trunk and tail, distinctiveness of all three rows of “portholes” on the trunk, and lack of distinct dorsal color pattern.
Distribution:
The species is currently known definitively from only six sites, one near the confluence of the Leaf and Chickasawhay Rivers in Green Co.,
Mississippi
; a nearby site on Sweetwater Creek, a tributary of Black Creek draining into the Pascagoula River in Perry Co.,
Mississippi
; one at Ward Bayou WMA on Ward Bayou of the Pascagoula River in Jackson Co.,
Mississippi
; two on a tributary of Franklin Creek within the city limits of Grand Bay, Mobile Co.,
Alabama
, draining into the Escatawpa River; and one along Chickasaw Creek, a tributary of the Mobile River. Strong evidence exists for a historical population in Baldwin Co.,
Alabama
, on the NE side of the Mobile-Tensaw River Delta. Additional historical and recent records of potentially conspecific individuals exist from Cumbest Bluff and other sites in Jackson Co.,
Mississippi
, within several kilometers of the
type
locality at Ward Bayou.
FIGURE 21.
Larger specimen (MMNS 19993/RAP1112) of
Desmognathus valentinei
from headwaters of West Creek, Harrison Co., Mississippi, beginning to showing typical adult coloration of “dark
auriculatus
”
sensu
Valentine (1963)
more typical of southeastern Mississippi populations. Note the more uniform and darker dorsal coloration and more brightly contrasting “portholes” in all three rows on the trunk.
FIGURE 22.
Large specimen (MMNS 19994/RAP1113) of
Desmognathus valentinei
from headwaters of West Creek, Harrison Co., Mississippi, showing typical adult coloration of “dark
auriculatus
”
sensu
Valentine (1963)
. Note the uniform melanistic dorsal coloration and brightly contrasting ventrolateral “portholes” on the trunk, nearly indistinguishable postocular stripe, and strongly keeled “fin-like” or “blade-like” tail, with lateral row of “portholes” barely visible.
Thus, confirmed sites include the
lower Pascagoula
, Escatawpa, and
Mobile River
drainages, while suspected sites enlarge this to include the Mobile-Tensaw Delta. The full geographic extent of
Desmognathus pascagoula
is unknown. In
Mississippi
to the west, sites from the
Mississippi
Coastal drainages and sites to the north from the
Lower Leaf River
drainage represent
D. valentinei
(
Figs. 7
,
8
;
Means
et al.
2017
). In
Alabama
, the northernmost extent along the Escatawpa is unknown.
Similarly, if the Tensaw specimen (AUM 10543) is in fact
D. pascagoula
,
then the species may range extensively to the north along the
Mobile
,
Alabama
, and
Tombigbee Rivers in Mobile
,
Baldwin
,
Clarke
,
Washington
, and
Monroe Co.
, and to the south and east in
Baldwin Co.
A
record of
D. auriculatus
from
Ferry Pass in Pensacola
,
Escambia Co.
,
Florida
(
Bishop, 1943
) could possibly represent the easternmost extent of the species, before it was historically replaced by what is currently considered
D. auriculatus
A in
Santa Rosa Co.
,
Florida
, east of the
Blackwater River
(
Means 1975
;
Means
et al.
2017
). A hiatus of
D. auriculatus
has historically been recorded between the
Blackwater
and
Perdido Rivers
in
Florida
(
Means 1999
, 2015).
All
historical populations of
D. pascagoula
east of
Grand Bay
and of
D. auriculatus
A west of the
Apalachicola River
are apparently extirpated (
Graham
et al.
, 2010
;
Means and Travis, 2007
).
Conservation:
The estimated range of the species encompasses numerous state and federal protected areas of relatively intact habitat, including the USFS De Soto National Forest, USFWS Grand Bay National Estuarine Research Reserve and Grand Bay and
Mississippi Sandhill Crane
National Wildlife Refuges, the ADCNR Forever Wild Grand Bay Savanna Tract and numerous WMA and FW tracts within the Mobile-Tensaw Delta complex, and the MDWFP Pascagoula River and Ward Bayou Wildlife Management Areas. In combination with the surface abundance of the known populations and their observed persistence over several years, we suggest that this species is likely of low conservation concern and should be assigned to the IUCN Red List categories “LC” or “NT” (
Maes
et al.
2015
).
We note that other swamp-dwelling populations of southeastern
U.S.
Coastal Plain dusky salamanders have declined drastically in recent years (
Dodd, 1998
;
Graham
et al.
, 2010
;
Hibbitts
et al.
, 2015
;
Maerz
et al.
2015
;
Means and Travis, 2007
), including
D. valentinei
in
Louisiana
(J. Boundy,
pers. comm.
). Furthermore, the potential for
D. pascagoula
to inhabit deeper, difficult to access microhabitats could make it challenging to detect and monitor populations. Thus, locating additional populations of this species and monitoring their health should be an immediate priority. At the Chickasaw Creek site, the ravine tributary originates in sight of
U.S.
Interstate 65, and during our visit the upper sections were filled with trash discarded from the roadway. Yet, an abundant salamander community nevertheless persists farther downstream where the intact hydrology supports sufficient microhabitat and vegetation. The site is heavily trafficked by humans and in close proximity (<
5 km
) to recreation, urban development, industrial activity, and interstate runoff. Other nearby sites with altered stream dynamics lacked this species or other salamanders, suggesting that hydrological damage, rather than environmental contamination, is a key driver of declines in this and potentially other swamp-dwelling species.