Williamson County, Texas, are both catalogued as MCZ 1627, but only
one of these bears a catalogue number. The two softshells are not
_emoryi_, and are more nearly like _T. s. guadalupensis_ than _T. s.
pallidus_. Actually, they are from an area of intergradation between
those subspecies (see comments concerning intergradation under the
accounts of the subspecies _pallidus_ and _guadalupensis_). White
spots occur on the carapaces anteriorly and posteriorly, the larger
(more posterior) of which are encircled with dusky ocelli. The
carapace of the small specimen (bearing no number) is brown having a
few, small black specks intermixed with the white spots. The carapace
of the large specimen is pale lavender and has a more obscure pattern
than the other specimen.
After Agassiz's description, _emoryi_ was accepted as a distinct
species. Neill (1951:15) suggested that _emoryi_ was subspecifically
related to _T. ferox_. Crenshaw and Hopkins (1955) and Schwartz
(1956), however, demonstrated that _ferox_ was a distinct species;
_emoryi_ has since been considered a subspecies of _T. spinifer_.
Two specimens having blackish dots on the carapace, indicate
relationship with _T. s. guadalupensis_. USNM 7638, a hatchling, has
large whitish dots surrounded by blackish dots confined to the
posterior half of the carapace, and the locality for this specimen is
merely Río Bravo (= Río Grande). CNHM 47366, a hatchling from Sierra
de las Palmas (Sierra de Santa Rosa, La Palma), Coahuila, has a few,
small, blackish dots, irregularly spaced, on the anterior half of the
carapace, but other dots more evenly distributed on the posterior half
where they are intermixed with whitish dots. The drawing of the dorsal
view of a hatchling _emoryi_ (Agassiz, 1857:Pl. 6, Fig. 4) shows a
sprinkling of blackish dots on the anterior half of the carapace. A
hatchling from Eagle Pass (USNM 116578) does not have a noticeably
widened pale rim posteriorly on the carapace, and is not
distinguishable from _pallidus_. See account of _T. s. guadalupensis_
for further comments on intergradation.
A soft-shelled turtle that was obtained in the Sacramento River by
three fishermen, near Sacramento, California, was named _Aspidonectes
californiana_ by Rivers (1889:233). A comparison (with _Aspidonectes
spinifer_ and _A. emoryi_) of certain features of the skull was
largely prepared by Baur and included in the description (_op.
cit._:234-35); seemingly, the most trenchant character of the skull of
_californiana_ was the enlarged alveolar surfaces of the jaws. This
feature prompted Baur (1893:220) to refer _californiana_ to the genus
_Pelodiscus_, which also included _agassizi_ (skulls also having jaws
with enlarged alveolar surfaces) and several Old World species. Van
Denburgh (1917) discussed the origin of the specimen that formed the
basis of River's description and concluded that it was brought over
from China. Siebenrock (1924:192) and Mertens and Wermuth (1955:389)
listed _Aspidonectes californiana_ as a synonym of _emoryi_. River's
description is not that of _emoryi_; the enlarged alveolar surfaces of
the jaws, and the dark carapace having tubercular ridges suggest a
resemblance to _T. ferox_. The papillae on the neck are not found in
any American species. Miller (1946:46, footnote 2) believed that "it
obviously was introduced, apparently from China," and cited Pope
(1935:61), who declared the specimen to represent _Trionyx sinensis_.
Schmidt (1924:64) first reported the occurrence of _T. s. emoryi_ west
of the continental divide in Arizona and suggested that it was highly
probable that the species had been introduced near Phoenix in recent
years. Cowles and Bogert (1936:42) mentioned a species of softshell
occurring in the Boulder Dam region and presumed the species to be
native to Asia and introduced by the Chinese. Linsdale and Gressitt
(1937:222) determined the status of the species in the Colorado River
drainage as _T. s. emoryi_. The discussions by Dill (1944:179-81) and
Miller (1946:46) indicate that _emoryi_ was introduced into the Gila
River (Colorado River drainage) in western New Mexico near the turn of
the century.
_T. s. emoryi_ and _T. ater_ are the only kinds of softshells
occurring in México. The colloquial name for soft-shelled turtles in
México is "tortuga blanca." This name is also used in reference to the
Central American river turtle, _Dermatemys mawei_, which occurs on the
east coast of México as far north as Veracruz.
_Specimens examined._--Total 275, as follows: ARIZONA: _Maricopa_:
CNHM 4768, KU 2214-19, 2803, 2824, 2837, 2903-07, 2909-16 (2914, 2
specimens), 2918-29, 3118-27, 3129, 3147-56, USNM 71627, Salt River,
Phoenix. _Pinal_: UI 37713, Gila River, 6 mi. E Winkleman; UMMZ
92006-07, Gila River, 1/2 mi. below Coolidge Dam; UMMZ 105824, San
Pedro River about 1 mi. above confluence with Gila River.
NEVADA: _Clark_: AMNH 58370, Boulder City boat landing, Lake Mead; TU
15802, Virgin River, Mesquite.
NEW MEXICO: _Eddy_: KU 15938, Carlsbad; KU 48217-18, Black River
Village. _Grant_: AMNH 79911, Gila River, 8 mi. NE Cliff.
TEXAS: _Brewster_: CNHM 39999, Tornillo Creek near jct. with Río
Grande; KU 51954-92, Lajitas; TCWC 4291, UMMZ 66471, USNM 45545,
103678, Boquillas; INHS 7975, UMMZ 114360, Hot Springs. _Cameron_: BCB
7564-73, CNHM 5339-40, 6810, MCZ 1909 (3), 1910, TU 11479-80,
11561-62, UMMZ 54021, 105209-13 (Brownsville Lake), USNM 7642, 7644,
7855, Brownsville; BCB 5121, 3 mi. S Harlington. _El Paso_: UMMZ
85085, El Paso; USNM 7641, 7701, El Paso del Norte. _Hudspeth_: USNM
20846, Fort Hancock on Río Grande. _Kinney_: CNHM 26090, Río Pinto W
of Bracketville; USNM 26426-36, Fort Clark. _Loving_: TTC 1143, Red
Bluff Lake just below dam on Pecos River. _Maverick_: TU 3696-97, UMMZ
116578, Eagle Pass. _Presidio_: TTC 628 (2), 632 (2), 3 mi. WNW
Lajitas, Brewster County. _Terrell_: TNHC 7997, 8022-23, Chandler
Ranch, 30 mi. S Sheffield, Pecos County; TNHC 8104, Dunlap Ranch, 25
mi. SE Sheffield, Pecos County; TU 14453 (7), 14462 (2), 15415, 15423,
15586, Pecos River near jct. with Independence Creek; USNM 104240,
Pecos River "near" Dryden. _Val Verde_: TTC 113, Pecos River. _Webb_:
TNHC 19788, 42 mi. NW Laredo; USNM 109078-79, Laredo. _Zapata_: UI
19332, "near" Zapata. _County unknown_: MCZ 1628, USNM 7635-36, 7854;
USNM 7637-38, Río Bravo (= Río Grande).
CHIHUAHUA: KU 51173, 8 mi. S, 16 mi. W Ojinaga; KU 51174-86, 1 mi. NW
Ojinaga; KU 51187-201, Río Conchos at mouth of Río San Pedro near
Meoquí; UI 43508-09, Río Florida, La Cruz.
COAHUILA: CNHM 26054, Sta. Helena Canyon of Río Grande; CNHM 28846,
"near" Músquis; CNHM 55657, Río Alamos, Rcho. de la Gacha; CNHM 47366,
Sierra de Santa Rosa, La Palma; CNHM 47367, 55661, Cuatro Ciénegas;
CNHM 55658-60, Rcho. de los Borregos near Juarez; KU 33523, La Presa
Don Martín; KU 39991, 39993, 8 mi. N, 2 mi. W Piedras Negras; KU
39992, 2 mi. W Jiménez; KU 46907, 16 km. S Cuatro Ciénegas; KU
46913-16, 10 km. S Cuatro Ciénegas; KU 53752-54, Río Mesquites, 8 mi.
W Nadadores; KU 53757, 8.5 mi. SW Cuatro Ciénegas; MSU 905-06, Río
Sabinas, 1 mi. E Sabinas.
NUEVO LEON: CNHM 1874, 2191, Rodriguez; UMMZ 69411, Río Conchos, 9 mi.
N Linares.
TAMAULIPAS: CM 3037, Nuevo Laredo. UMMZ 7614-20, 7622-25, 7628, 7630,
7632-33, Matamoros; UMMZ 69412, Río Purificación, N of Ciudad
Victoria.
NO DATA: MCZ 1629 (2), NHB 1032.
_Records in the literature._--ARIZONA: _Greenlee_: Gila River, Duncan
(Miller, 1946:46); "near" Sheldon (Dill, 1944:180). _Mohave_: Pierce's
Ferry just below lower end of Grand Canyon (Cowles and Bogert,
1936:42); 1.5 mi. upstream (Virgin River) from Mesquite, Clarke
County, Nevada (Hardy and Lamoreaux, 1945:168); Lake Havasu on
Colorado River (Dill, 1944:180). _Yuma_: Colorado River at Headgate
Rock Dam (Dill, _op. cit._:179).
CALIFORNIA: _Imperial_: California Lakes (Cowles and Bogert, 1936:42);
Palo Verde; Colorado River at Laguna Dam (Dill, 1944:180).
NEVADA: _Clark_: observed just north of Black Canyon (Cowles and
Bogert, _loc. cit._); Colorado River, 6 mi. N California line
(Linsdale, 1940:255).
NEW MEXICO: _Chaves_: Bitter Lakes Wildlife Refuge, 12 mi. NE Roswell
(Bundy, 1951:314). _Dona Ana_: Río Grande near Mesilla Dam (Little and
Keller, 1937:221).
TEXAS: _Brewster_: Río Grande at Castolon (Minton, 1959:38). _Val
Verde_: mouth of Devil's River (Brown, 1950:250).
BAJA CALIFORNIA: Colorado River delta, 7 mi. E Cerro Prieto; Imperial
Irrigation District, Alamo Canal, 15 mi. S Internat'l Boundary and
Salfatana Canal, 1 mi. N Black Butte (Linsdale and Gressitt,
1937:222).
COAHUILA: San Juan (Schmidt and Owens, 1944:103).
Hitherto, soft-shelled turtles of the species _Trionyx spinifer_ from
the southern and southwestern United States having a pattern of white
dots on the carapace have been relegated to the subspecies _emoryi_,
but my examination of soft-shelled turtles from Texas has indicated
that _T. s. emoryi_ as previously conceived, is a composite of three
subspecies. It is necessary, therefore, to recognize two new
subspecies.
=Trionyx spinifer guadalupensis= new subspecies
Guadalupe Spiny Softshell
Plates 41 and 42
_Holotype._--UMMZ 89926, alcoholic adult male; obtained 15 miles
northeast Tilden, McMullen County, Texas (Pl. 41, bottom, left).
_Paratypes._--Forty-two specimens: ANSP 16717 (hatchling), no data;
USNM 78515-16 (hatchlings), Colleto Creek, Victoria County, Texas; TU
10143-45, 10148, 10150-59, 10161-65 (adult males), TU 10176, 10833
(immature males), TU 10147, 10149, 10155 (immature females), TU 10160
(adult female), Guadalupe River, 9 miles southeast Kerrville, Kerr
County, Texas; UMMZ 89915-21, 89924-27 (adult males), UMMZ 89922-23
(immature females), same locality as holotype; UMMZ 92752 (immature
female), San Antonio River, 3 miles west-northwest Goliad, Victoria
County, Texas.
_Description of holotype._--Carapace nearly circular, widest at level
of posterior border of hypoplastra; margin entire; dorsal surface
"sandpapery" to touch; pale rim separated from ground color of
carapace by well-defined, blackish line that is wavy and narrowly
interrupted posteriorly and anteriorly; pale rim approximately 1.8
times wider posteriorly (5.4 mm.) than laterally (3.0 mm.); pale rim
increasingly narrower anteriorly, absent in nuchal region; tubercles
in nuchal region low, scarcely elevated, lacking sharp tips; ground
color of carapace olive having pattern of whitish spots and small
tubercles; most whitish tubercles inconspicuous pinpoints; other small
tubercles in center of whitish spots, mostly approximately 2
millimeters in diameter; largest white spot 3.4 millimeters in
diameter; most white spots surrounded by blackish ocelli or parts
thereof; whitish spots distributed over entire surface of carapace;
certain features of bony carapace evident through overlying skin;
carapace highest in region of second and third neurals, forming
obtuse, gently sloping, vertebral, keel; undersurface of carapace
butterscotch yellow, lacking markings; maximum length, 16.5
centimeters; greatest width, 13.5 centimeters.
Plastral surface butterscotch yellow, lacking markings, extending
slightly farther forward than carapace; anterior and posterior lobes
rounded; anterior lobe slightly truncate; certain features of bony
elements of plastron visible through overlying skin; maximum length of
plastron, 12.0 centimeters.
Head, extended to posterior level of eyes, terminating in flexible
snout; septal ridges projecting into each rounded nostril; jaws
closed, each covered by fleshy lips except anteriorly where horny
portions exposed; dark triangular mark in front of eyes, base line
connecting anterior margins of orbits forming series of dots; pale
stripes extending forward from eyes having faint inner, blackish
borders; eyelids partly open having blackish dots; pale subocular
blotch on right side of head having border of black dots.
Forefeet and hind feet well-webbed having five digits each; each limb
having nails on first three digits; each forelimb with four
antebrachial scales, three of these having free edge; each hind limb
with two horny scales, one smooth on posterodorsal surface and other
with free edge on posteroventral surface; pattern toward insertion of
forelimbs indistinct.
Tail terminating in flexible point; penis exposed; cloacal opening
extending beyond posterior edge of carapace; tail olive above bordered
by blackish marks; few black dots laterally on left side.
Undersurface of soft parts of body buff, lacking markings; few dark
marks posteriorly on webbing of limbs, encroaching on soles and palms.
_Range._--Southcentral Texas in the drainage systems of the Nueces and
Guadalupe-San Antonio rivers; the Colorado River drainage in Texas is
inhabited by a population that more closely resembles _guadalupensis_
than _pallidus_. See comments under subsection entitled "Remarks" and
Fig. 19.
_Diagnosis._--Juvenal pattern of white dots that are conspicuous on
anterior half of carapace, and usually as large as those on posterior
half; white dots, sometimes 3 millimeters in diameter, encircled with
blackish ocelli in adult males.
_Description._--Plastral length of smallest hatchling, 3.3 centimeters
(ANSP 16717); of largest male, 13.5 centimeters (TU 10162); of largest
female, 22.0 centimeters (TU 10160).
Hatchlings having white dots on anterior half of carapace; white dots
anteriorly nearly as large as those posteriorly, encircled with
blackish ocelli, and conspicuous on dark background (ANSP 16717, Pl.
41; USNM 78515-16; Stebbins, 1954:181, Pl. 26B), or smaller than those
posteriorly, not encircled with dusky ocelli, and inconspicuous on
pale background (TNHC 1446); pale rim of carapace less than four times
as wide posteriorly as laterally.
Adult males resembling holotype; size of white tubercles on carapace
variable; most, if not all, tubercles surrounded by narrow blackish
ocelli, or parts thereof; largest white tubercles or dots in most
specimens exceeding one millimeter and in some specimens three
millimeters in diameter (TU 10163); white dots often slightly elongate
(UMMZ 89917, 89920, 89926; TU 10152, 10145); juvenal pattern of white
dots seemingly more contrasting in _guadalupensis_, owing to dark
ground color of carapace, than in _pallidus_ or _emoryi_ that have
pale brown or tan carapaces; small tubercles along anterior edge of
carapace rounded, obtuse, wartlike, never conical; sharp tips often
lacking (TU 10153).
Large females often having whitish spots on anterior half of carapace
(TU 10160, Pl. 42, upper, right; 10142); carapace dark having
ill-defined mottled and blotched pattern; tubercles along anterior
edge of carapace low, rounded, rarely equilateral, never conical;
small blackish dots rarely on surface of carapace (UMMZ 89923).
Pattern on side of head and snout of little diagnostic value;
postocular stripe usually interrupted, but configuration variable,
consisting of pale anterior, dark-bordered segment (just behind eye);
posterior segment of postocular stripe usually less well-defined and
generally blending with adjacent ground color; pale postocular stripe
sometimes uninterrupted and dark-bordered throughout its length (TU
10157, 10159, 10176); pattern on dorsal surface of snout variable;
pattern usually consisting of uninterrupted dark line (slightly curved
anteriorly) connecting anterior margins of orbits (TU 10161, 10164,
10159, 10143), or dark line interrupted (TU 10153, 10154, 10176),
absent (TU 10163), or present in addition to dark inner borders of
pale stripes that extend anteriorly from eyes (TU 10149, 10162);
small, often fine, dark markings, on dorsal surface of limbs,
especially forelimbs; ventral surface of plastron and soft parts of
body usually whitish, lacking markings; small blackish spots
occasionally in region of bridge (TU 10149); dark marks occurring on
webbing of limbs and often encroaching on soles and palms.
Ontogenetic variation in PL/HW, mean PL/HW of specimens having
plastral lengths 7.0 centimeters or less, 3.83, and exceeding 7.0
centimeters, 5.18; ontogenetic variation in CL/CW, mean CL/CW of
specimens having plastron lengths 8.5 centimeters or less, 1.14, and
exceeding 8.5 centimeters, 1.22; mean CL/PCW, 2.11; mean HW/SL, 1.38
(including subspecies _pallidus_); mean CL/PL, 1.37.
_Variation._--Two hatchlings (ANSP 13447, Bexar County; TNHC 1446,
McMullen County) more closely resemble _pallidus_ than
_guadalupensis_.
Some individuals from the Colorado River drainage have features
suggesting those that are characteristic of _pallidus_. Large females
have obtuse, knoblike somewhat triangular-shaped tubercles along the
anterior edge of the carapace, which are never conelike (TU 14439-40,
10187, 16036.1; BCB 6010). The tubercles along the anterior edge of
the carapace are more elevated than in turtles from drainage systems
west of the Colorado. Whitish spots are usually absent anteriorly on
the carapace, but may be evident through the mottled pattern of large
females (BCB 6010, plastral length, 19.7 cm.). The pale postocular
stripe is usually interrupted, whereas the dark line connecting the
anterior margins of the orbits is usually not interrupted; the two
characters last mentioned show alliance with _guadalupensis_.
The carapace of hatchlings from the Colorado River is pale having
whitish dots, smaller anteriorly than posteriorly, which may be
encircled with dusky ocelli (TNHC 20257) or not (ANSP 11889, BCB 5055,
SM 3282). Many hatchlings are not distinguishable from _pallidus_
(TCWC 7262, TNHC 4975, SM 4924, 6106). I have not seen hatchlings from
the Colorado River that resemble ANSP 16717.
The pattern on the carapace of adult males from the Colorado River
drainage resembles that of _guadalupensis_ (Pl. 41, bottom, right) but
the whitish dots are usually smaller and may not be encircled with
blackish ocelli (BCB 4066, TU 14485). An adult male (TU 14476) from
the South Fork of the Llano River has whitish dots three millimeters
in diameter and encircled with blackish ocelli (_guadalupensis_),
whereas another adult male (USNM 83690) from a tributary of the
Colorado, the South Concho River, resembles _pallidus_.
Eight specimens from the San Saba River (TU 14419 [6 specimens],
14439-40), that range in plastral length from 6.8 to 17.0 centimeters
are impressive because of the dark brownish coloration on the
carapace. The smallest individual, which is also the only male in the
series, is paler. The mottled and blotched pattern on the females is
therefore not contrasting; the largest females have elevated whitish
prominences in the center of the carapace posteriorly. An immature
male (UMMZ 70348) from the South Concho River also has a dark brown
carapace, and lacks white dots. The dark coloration of the carapace of
these specimens recalls the TU series of _T. s. emoryi_ from the Pecos
River, Terrell County, Texas.
Color notes taken from a freshly-killed adult female from the Llano
River, two miles west Llano (TU 16036.1, Pl. 42), are: pattern on
carapace of dark olive or blackish marks that form an irregular
reticulum or marbling on a paler background that varies from brownish
to buff and has an orange or reddish tinge in some areas; small
whitish spots posteriorly; pale rim yellowish, evident only at sides
of carapace; dorsal surface of soft parts of body olive-green,
becoming paler with yellowish tinge toward insertions of limbs and
neck; no contrasting pattern on limbs or neck and head; yellowish on
sides of body; ventral surface whitish lacking dark marks, yellowish
at region of bridge, axillary region and on neck; chin olive-yellow.
_Comparisons._--_T. s. guadalupensis_ can be distinguished from all
other subspecies of _T. spinifer_ in having: (1) large white dots,
sometimes three millimeters in diameter, on a dark background usually
surrounded with blackish ocelli and conspicuous on the anterior half
of the carapace (some as large as those on posterior half) in adult
males, and (2) whitish dots on the anterior half of the carapace, in
hatchlings, that are often encircled with dark ocelli. _T. s.
guadalupensis_ resembles _pallidus_ and _emoryi_ in having white
tubercles or dots on the carapace and therein differs from _spinifer_,
_hartwegi_ and _asper_. _T. s. guadalupensis_ resembles _pallidus_ but
differs from _emoryi_ in having a pale rim that is less than four
times wider posteriorly than laterally. _T. s. guadalupensis_
resembles _emoryi_ but differs from _pallidus_, _spinifer_, _hartwegi_
and _asper_ in having along the anterior edge of the carapace
tubercles that are flattened or wartlike prominences often lacking
sharp tips in adult males; these tubercles are never conical in large
females.
_T. s. guadalupensis_ has a wide head, a feature shared with the
subspecies _asper_ and _emoryi_, but differs from _emoryi_ in having a
wider carapace. _T. s. guadalupensis_ resembles _emoryi_ and
_pallidus_ but differs from the other subspecies in having the
carapace widest farther posterior than one-half the length of the
carapace. The length of snout in _pallidus_ and _guadalupensis_ is
shorter than in _spinifer_ and _hartwegi_ but is longer than in
_emoryi_. _T. s. guadalupensis_ differs from _asper_ but resembles the
other subspecies in having a relatively long plastron.
_Remarks._--Some individuals of _guadalupensis_ have characteristics
that are applicable to _emoryi_. TNHC 12352 (Llano River) a hatchling,
has conspicuous white dots confined to the posterior third of the
carapace; the pale rim, however, is not widened posteriorly. TU 10156
(Guadalupe River) has a conspicuously widened pale rim on the carapace
that is approximately 3.4 times wider posteriorly (8.5 mm.) than
laterally (2.5 mm.).
_T. s. guadalupensis_ more closely resembles _pallidus_ than _emoryi_.
Turtles living in rivers that drain into the Gulf of Mexico east of
the Guadalupe-San Antonio river system successively show increasing
resemblance to _pallidus_ from west to east.
The expression of intergradation between _guadalupensis_ and
_pallidus_ is of a clinal nature that involves parallel changes in the
pattern on the snout, side of head, limbs (to a lesser degree),
tuberculation along the anterior edge of the carapace, size of whitish
tubercles or dots, and the distinctness of the blackish ocelli that
surround the whitish dots on the carapace. These characters form a
well-marked gradation or cline that extends over a considerable area.
There is, however, no continuous environmental gradient because the
populations are relatively isolated by occupying adjacent drainage
systems. The sharpest break in the gradation of characters mentioned
above occurs between the Colorado River and Brazos River drainages.
The population of softshells in the Colorado River drainage is
actually an intergradient one, but more closely resembles
_guadalupensis_, whereas the population in the Brazos River drainage
more closely resembles _pallidus_. For convenience the turtles
inhabiting the Colorado River drainage are referred to _guadalupensis_
and those in the Brazos River drainage to _pallidus_. Some individuals
from farther west than the Colorado River drainage will resemble
_pallidus_, and a few individuals from father east than the Brazos
River drainage will resemble _guadalupensis_.
The gradation of some of the characters mentioned above terminates in
the subspecies _emoryi_. It, however, has characters not found in
_pallidus_ or _guadalupensis_, and is more distinct from either of
those subspecies than either is from each other; the difference in
characters as well as the break in the gradient of characters between
_guadalupensis_ in the Nueces River drainage and _emoryi_ in the Río
Grande drainage is greater than that between _guadalupensis_ in the
Colorado and _pallidus_ in the Brazos River drainages.
I have refrained from designating individuals between these three
subspecies (_emoryi_, _guadalupensis_ and _pallidus_) as "intergrades"
on the distribution maps, and only mention (in text) those individuals
whose characters show a decided tendency toward the adjacent
subspecies. For further comments on intergradation see the account of
_T. s. pallidus_.