North American Recent Soft-shelled Turtles (Family Trionychidae) Part 7

_Trionyx ferox_ Schwartz, Charleston Mus. Leaflet, No. 26:17, pls. 1-3, May, 1956.

_Testudo mollis_ Lacepede, Hist., Nat. Quadr. Ovip. Serp., 1:137, pl. 7, 1788.

_Testudo_ (_ferox_?) verrucosa Schoepff, Hist. Testud., Fasc. 5 (Plag. M):90, pl. 19, 1795.

_Testudo bartrami_ Daudin, Hist. Nat. Rept., 2:74, pl. 18, fig. 2, 1801.

_Trionyx georgicus_ Geoffroy, Ann. Mus. Hist. Nat., Paris, 14:17, August, 1809.

_Mesodeca bartrami_ Rafinesque, Atlan. Jour., Friend Knowledge, Philadelphia, 1 (No. 2, Art. 12):64, Summer, 1832.

_Trionyx harlani_ Bell in Harlan, Medic. Phys. Research, p. 159, 1835.

_Type._--Holotype, British Museum (Natural History) 1947.3.6.17; original number 53A, presumably that of Royal Society; stuffed adult female and skull; obtained from the Savannah River, Georgia, by Dr. Alexander Garden.

_Range._--Southern South Carolina, southeastern Georgia, and all of Florida except the Keys and perhaps the western end of the panhandle (see map, Fig.

18).

[Ill.u.s.tration: FIG. 18. Map of southeastern United States showing geographic distribution of _Trionyx ferox_.]

_Diagnosis._--Marginal ridge present; longitudinal rows of tubercles that resemble ridges on carapace of hatchlings; plastron often extending farther forward than carapace in adults; plastral area dark slate or gray in hatchlings; juvenal pattern of large slate or blackish blotches (often with pale centers) on a pale background; pale outer rim of carapace (absent on adults) narrow, not separated from ground color of carapace by distinct, dark line.

Size large; head wide; carapace relatively long and narrow; snout short; greatest width of skull at level of quadratojugal; often no suture between hypoplastra and hyoplastra; callosities on epiplastron and preplastra usually lacking.

_Description._--Plastral length of smallest hatchling, 2.9 centimeters (UMMZ 95613), of largest male, 26.0 centimeters (AMNH 63642), of largest female, 34.0 centimeters (UMMZ 38123).

Septal ridges present; over-all coloration of carapace and plastron, and soft parts of body of hatchlings slate or blackish; carapace having blackish, circular blotches, usually fused at margin, often with pale centers on buff background forming coa.r.s.e reticulum; pale, narrow rim of carapace not separated from ground color by dark marginal line; pale rim, coincident with marginal ridge, absent from anteriormost nuchal region; longitudinal rows of tubercles on carapace resembling ridges; undersurface blackish, usually having posterior part of carapace pale with irregular blackish marks; blackish soft parts of body dorsally having large, pale markings, most consistent of which are postocular mark that may contact orbit, postl.a.b.i.al mark that curves around angle of jaws, inverted Y on top of snout, and one or two streaks on side of neck.

Over-all coloration of adults grayish, paler than in hatchlings; carapace gray sometimes having slightly darker, large, irregular markings; mottled and blotched pattern on females not contrasting; s.e.x of many large individuals not distinguishable on basis of pattern on carapace; pale rim of carapace obscure or absent; soft parts of body dorsally gray or brownish on large adults of both s.e.xes, sometimes having slightly paler, large markings; small adult males usually having contrasting pattern on head; surface of carapace smooth (not "sandpaper") on adult males; undersurface whitish, throat often grayish; well-defined marginal ridge; anterior edge of carapace laterally to region of insertion of forelimbs studded with low, flattened tubercles resembling hemispheres, never conical; carapace usually having blunted tubercles, best developed anteriorly and posteriorly on midline, but sometimes linearly arranged, resembling ridges, especially at margins; anterolateral parts of plastron often extending farther forward than corresponding parts of carapace.

Range in length (in cm.) of plastron of ten largest specimens of each s.e.x (mean follows extremes), males, 17.0-26.0, 20.0; females 23.3-34.0, 27.9; ontogenetic variation in PL/HW, mean PL/HW of specimens having plastral lengths 6.5 centimeters or less, 3.52, and exceeding 6.5 centimeters, 4.87; ontogenetic variation in CL/CW, mean CL/CW of specimens having plastral lengths 8.0 centimeters or less, 1.18, and exceeding 8.0 centimeters, 1.30; mean CL/PCW, 2.01; mean HW/SL, 1.44; mean CL/PL, 1.26.

Jaws of some skulls that exceed 75 millimeters in basicranial length having expanded alveolar surfaces; greatest width of skull usually at level of quadratojugal (72%); ventral surface of supraoccipital spine narrow proximally, usually having medial ridge; foramen magnum rhomboidal; opisthotic-exoccipital spur absent (82%), sometimes indicated by ridge (16%); distal part of opisthotic wing tapered, not visible in dorsal view; lateral condyle of articular surface of quadrate larger than medial articular surface, not tapered posteriorly; maxillaries in contact above premaxillaries; usually a combination of seven neurals, seven pairs of pleurals, and contact of seventh pair of pleurals (56%), often eight pairs of pleurals (31%); angle of epiplastron forming approximate right angle; often no suture between hypoplastra and hyoplastra; callosities on preplastra and epiplastron usually lacking.

_Variation._--Crenshaw and Hopkins (1955:19) stated that in specimens from Lake Okeechobee and southward the carapace is wider relative to the width of the head, and Neill (1951:19) quoted Allen's observations that _ferox_ from southern Florida "average larger and darker than those collected farther north."

Carr (1952:417) reported that the pale reticulum on the carapace is yellowish olive, the markings on head are yellow on an olive ground color, some markings more orange, and the plastron slate gray. Duellman and Schwartz (1958:271) mentioned that the carapace of hatchlings is edged in orange grading to yellow posteriorly and has a pattern of bluish-black blotches on a dull brown background, whereas the carapace is dull brown or blackish on adults. Neill (_op. cit._:18) wrote "that the head stripes and the marginal ring of the 'carapace' are orange rather than yellow (yellow at the time of hatching, however)."

The transition from the dark coloration of hatchlings to the paler coloration of adults is gradual and subject to individual variation. The loss of dark color ventrally occurs first on the plastral area, then the hind limbs, forelimbs, posterior part of carapace and last on the neck and throat. The soft parts of the body dorsally are gray or dark gray, and do not become so pale as the ventral surface. The smallest specimen that I have seen displaying the dark features of the hatchlings is a male, 7.7 centimeters (UMMZ 100673); a female, 9.5 centimeters (UMMZ 110987), is the smallest specimen having a whitish plastral area. The change from dark to pale coloration on the ventral surface occurs at a size of 8.0 to 9.0 centimeters. The largest specimens I have seen having indistinct, dusky blotches of the underside of the carapace are a female, 11.3 centimeters (UMMZ 100836), and a male, 16.0 centimeters (UMMZ 106322). A contrasting pattern on head and limbs, and a dark throat are still evident in a female 19.2 centimeters (UMMZ 106302).

_Comparisons._--_Trionyx ferox_ can be distinguished from all other species of the genus in North America by the presence of a marginal ridge, longitudinal ridges of tubercles on the carapace of juveniles (less evident in adults), and the unique juvenal pattern and coloration. The lack of a juvenal pattern and a smooth surface on the carapace (not gritty like sandpaper) distinguish adult males from those of _T. spinifer_. Most adults of both s.e.xes can be distinguished from _spinifer_ and _muticus_ by the extension of the plastron farther forward than the carapace (developed to a slight degree in some specimens of _T. s. emoryi_). Both s.e.xes of all ages can be distinguished from _muticus_ by the presence of k.n.o.blike tubercles on the anterior edge of the carapace, and septal ridges.

_T. ferox_ is the largest species in North America; the maximum size of the plastron in adult males is approximately 26.0 centimeters (16.0 in _spinifer_) and of adult females, 34.0 centimeters (31.0 in _spinifer_). The head is wider in _ferox_ than in _muticus_ and most subspecies of _spinifer_ (closely approached by _asper_, _guadalupensis_, _emoryi_ and _T. ater_). The carapace is narrower in _ferox_ than in _muticus_ and most subspecies of _spinifer_ (closely approached by _emoryi_ and _T. ater_). The snout is shortest in _ferox_, but almost as short in _T. s. emoryi_ and _T. ater_. _T. ferox_ has proportionately the longest plastron in relation to length of carapace.

Most skulls of _ferox_ differ from those of _muticus_ and _spinifer_ in having the greatest width at the level of the quadratojugal (as do some _T. s. asper_; see account of that subspecies). In the skull, _ferox_ resembles _spinifer_ but differs from _muticus_ in having the 1) ventral surface of the supraoccipital spine narrow proximally, and usually having a medial ridge, 2) foramen magnum rhomboidal, 3) distal part of opisthotic wing tapered, 4) lateral condyle of articular surface of quadrate not tapered posteriorly, and larger than medial articular surface, and 5) maxillaries in contact above premaxillaries. _T. ferox_ resembles _muticus_ but differs from most individuals of _spinifer_ in lacking a well-developed opisthotic-exoccipital spur. _T. ferox_ resembles _spinifer_ but differs from _muticus_ in having the epiplastron bent at approximately a right angle; _ferox_ differs from both _muticus_ and _spinifer_ in lacking a callosity on the epiplastron and probably in the more frequent fusion of the hyoplastra and hypoplastra.

_Remarks._--The early taxonomic history of _Trionyx ferox_ has been discussed in detail by Stejneger (1944:27-32), who explained that Dr. Alexander Garden of Charleston, South Carolina, sent a description and specimen of _T. ferox_ to Thomas Pennant, and at the same time sent another specimen with drawings to a friend, John Ellis, in London. Pennant presented one of the specimens and drawings and the description to the Royal Society of London in 1771; the description was published in 1772 and included Garden's drawings.

Because two specimens were involved the possibility exists that the description (text, drawings and type specimen) is a composite based on two specimens.

I have not seen the type. Garden's original description (_in_ Pennant, 1772:268-271) leaves little doubt that the text subject is a large adult female of _ferox_ (see especially the statements, "fore part, [of carapace] just where it covers the head and neck, is studded full of large k.n.o.bs, [and] The under, or belly plate, ... is ... extended forward two or three inches more than the back plate, ..."). I am indebted to Mr. J. C. Battersby, British Museum (Natural History), Department of Zoology (Reptiles), for information concerning the type and for comparing it with the text description and three figures published by Pennant. The carapace of the type is approximately 16 inches long, 13-1/2 inches wide, and has low, flattened, k.n.o.blike tubercles along the anterior edge. Some inaccuracies on the part of the artist (such as five claws on both feet on the right side of Fig. 3, and four claws on the left front foot of Fig. 2 are evident), and slight changes in the proportions of the type would have occurred after death and preservation. It is the opinion of Mr. Battersby that the type, text description and three figures represent one specimen. Figures 1 and 2, dorsal and ventral views respectively, probably represent the same specimen from life; the neck is withdrawn and the tail tip is visible in dorsal view, but concealed beneath the posterior edge of the carapace in ventral view. Presumably the same specimen (probably drawn from dried and stuffed animal) is depicted in Figure 3 (dorsal view); the neck is fully extended and a large part of the thick, pyramidal tail is visible in dorsal view. British Museum (Natural History) 1947.3.6.17 is considered a holotype. The three figures published by Pennant have been duplicated by Schoepff (1795:Pl. 19) and Dumeril and Bibron (1835:482). To my knowledge, the holotype was first specifically designated as the "(Type.)" of _T. ferox_ by Boulenger (1889:259). The skull of the holotype is figured by Stejneger (1944:Pl. 5).

Garden did not list a specific locality for the two specimens that he sent to London, but did mention that the turtle was common in the Savannah and Altamaha rivers (of Georgia), and rivers in east Florida. Boulenger (_loc. cit._) stated that the locality of the holotype was "Georgia." Baur (1893:220) restricted the type locality to the "Savannah river, Ga." Neill (1951:17), who believed _T. ferox_ to be absent from the Savannah River, changed the type locality of _ferox_ to east Florida. Schwartz (1956:8) reappraised the status of softsh.e.l.ls in Georgia and Florida and reestablished the Savannah River (at Savannah), Georgia, as the type locality of _T. ferox_.

Pennant failed to use binomial nomenclature when he published the type description of Garden. The first name-combination (_Testudo ferox_) was proposed by Schneider (1783:220).

Lacepede (1788:137, Pl. 7) referred to Garden's description in Pennant only as "The Molle" but on a folded paper chart ent.i.tled "Table Methodique des Quadrupedes ovipares," which is inserted after an introduction of 17 pages, listed _T. mollis_; this name is again listed on another folded chart, ent.i.tled "Synopsis methodica Quadrupedum oviparorum," which is inserted between pages 618 and 619 under the genus _Testudo_. The ill.u.s.tration (Pl. 7) was taken from Pennant (Dumeril and Bibron, _loc. cit._). The type locality has been designated "(following Stejneger, 1944) as eastern Florida" by Schmidt (1953:108).

Bartram failed to use a binomial name with his description of "the great soft sh.e.l.led tortoise," which appeared in his _Travels_ (1791:177-179, Pl. 4 and unnumbered plate between pages 282 and 283) and two editions of a French translation (1799 and 1801, 1:307); see Harper (1940). Recently, Bartram's _Travels_ has been placed on the Official Index of Rejected and Invalid Works in Zoological Nomenclature, Opinion 447 (see Hemming, 1957). Bartram's description of a soft-sh.e.l.led turtle has provided the basis for the proposal of at least three name-combinations. The first was _Testudo_ (_ferox?_) _verrucosa_ proposed in 1795 by Schoepff; it appeared simultaneously in _The Historia Testudinum_ and in a German translation, _Naturgeschichte der Schildkroten_ (see Mittleman, 1944:245). Stejneger (1944:26) listed the type locality as eastern Florida. Daudin (1801:74), also referring to Bartram's description in his _Voyage_ (French translation), proposed the name _Testudo bartrami_; Harper (_op. cit._:717) restricted the type locality of _T. bartrami_ from "Halfway pond," east Florida, to southwestern Putnam County between Palatka and Gainesville, Florida. Rafinesque (1832:64-65), relying on the authenticity of the ill.u.s.trations in Bartram's _Travels_ that depict a soft-sh.e.l.led turtle having five claws on each of the hind feet, tubercles on the sides of the head and neck, and ten scales in the middle of the carapace (presumably inaccuracies or a composite on the part of the artist), referred to Bartram's description as a new genus, _Mesodeca bartrami_, a name which Boulenger (1889:245, footnote) referred to as "mythical." Geoffroy (1809a:18-19) considered Bartram's description the basis for the recognition of a second species of _Chelys_ (binomial nomenclature not employed), and Dumeril and Bibron (_loc. cit._) suggested that the description was based partly on a "Chelyde Matamata."

The descriptive comments of Bartram are not clearly applicable to _Testudo ferox_ Schneider; _Trionyx ferox_, however, is the only species of soft-sh.e.l.led turtle known to occur in the region of Bartram's observations (east Florida), and the type locality was restricted to Putnam County, Florida, by Harper.

The name-combinations, _Testudo___ (_ferox?_) _verrucosa_ Schoepff, _Testudo bartrami_ Daudin, and _Mesodeca bartrami_ Rafinesque are junior synonyms of _Testudo ferox_ Schneider.

Schweigger (1812:285) referred _ferox_ to the genus _Trionyx_ following the description of that genus by Geoffroy in 1809. _Testudo ferox_ was listed as a synonym by Geoffroy in the description of _Trionyx georgicus_ (1809a:17); Dumeril and Bibron (1835:432) mentioned that the specific characters of _georgicus_ were taken from Pennant. The name _Trionyx georgia.n.u.s_ presumably appears for this taxon in Geoffroy's earlier-published synopsis (1809:367).

_T. georgicus_ was listed as occurring in rivers of Georgia and the Carolinas; the type locality was restricted by Schmidt (_op. cit._:109) to the Savannah River, Georgia. The two specific names _georgicus_ and _georgia.n.u.s_ are regarded as subst.i.tute names and junior synonyms of _T. ferox_.

Geoffroy (1809a:14-15) also described _Trionyx carinatus_, a name-combination that hitherto has been considered a synonym of _Trionyx ferox_. There is no indication from the description that _carinatus_ is applicable to _ferox_.

Most comments pertain to a description of the bony carapace and plastron, which Geoffroy depicts in Plate 4. It is a young specimen judging from the small and isolated preneural; the seventh pair of pleurals is unusual in being fused (no middorsal suture), and the neurals seem large in proportion to the size of the pleurals. The anterior border of the carapace is described as having tubercles. Geoffroy listed _Testudo membranacea_ and _Testudo rostrata_ as synonyms of _carinatus_. Fitzinger (1835:127) listed _T. membranacea_, _T. rostrata_ and _T. carinatus_ as synonyms of _Trionyx javanicus_ (= _T. cartilagineus_), which was also described by Geoffroy (_op. cit._:15).

Dumeril and Bibron (_op. cit._:478, 482) considered _carinatus_ to be the young of _spinifer_ (_ferox_ as synonym). Gray (1844:48), however, referred _T. membranacea_ and _T. rostrata_ to the synonymy of _T. javanicus_, but considered _T.

carinatus_ to be a synonym of _T. ferox_ (_op. cit._:50), an interpretation followed by all subsequent authors. _Trionyx carinatus_ is questionably listed as a synonym of _ferox_ by Stejneger (1944:27). Dumeril and Bibron (_op. cit._:482) wrote that the young type of _carinatus_ is in the museum at Paris. Dr. Jean Guibe informs me in letter of September 24, 1959, that the type of Geoffroy's _T. carinatus_ cannot be found in the Natural History Museum at Paris. For the present, _T. carinatus_ is considered a _nomen dubium_. According to Stejneger (1944:27), _Trionyx brongniarti_ Schweigger is a subst.i.tute name for _T. carinatus_.

I am unable to add anything to Stejneger's (_op. cit._:32) account of _Trionyx harlani_; the mention of its occurrence in east Florida indicates that it is indistinguishable from _Testudo ferox_ Schneider.

_T. ferox_ was considered to be indistinguishable from Lesueur's _Trionyx spiniferus_ (described in 1827), until Aga.s.siz (1857:401) pointed out the differences between the two species. However, Aga.s.siz (_op. cit._:402, Pl. 6, Fig.

3) regarded juveniles of _T. spinifer asper_ as the young of _ferox_. Consequently, the geographic range of _ferox_, as envisioned by Aga.s.siz, extended from Georgia and Florida west to Louisiana. Neill (1951:15) considered all American forms conspecific. Crenshaw and Hopkins (1955) and Schwartz (1956) demonstrated that _ferox_ is a distinct species.

Fitzinger (1843:30) designated the species _ferox_ as the type species of his genus _Platypeltis_ as follows: "Platypeltis. Fitz. Am[erica]. _Platypelt.

ferox_. Fitz. Typus." If populations of soft-sh.e.l.led turtles that are referable to _Testudo ferox_ Schneider are considered to comprise a distinct genus by future workers, _Platypeltis_ Fitzinger, 1835, is available as a generic name with _Testudo ferox_ Schneider, 1783, as the type species (by subsequent designation).

_Trionyx ferox_ in the northern part of its range is sympatric with _T. spinifer asper_. In the region of overlap, the two species are nearly always ecologically isolated; _ferox_ inhabits lentic waters, whereas _T. s. asper_ is partial to lotic waters (Crenshaw and Hopkins, _op. cit._:16). There is no evidence of intergradation or hybridization.

Many characters of _Trionyx ferox_ that are lacking in other North American forms are shared with some Asiatic softsh.e.l.ls, such as the large size, longitudinal rows of tubercles that resemble ridges on the carapace, and the marginal ridge. It is thought that, of the living softsh.e.l.ls in North America, _ferox_ is more closely allied to Old World forms of the genus than to _muticus_ or _spinifer_.

Carr (1940:107) recorded _ferox_ from Okaloosa County, Florida, in the western end of the panhandle, whereas Crenshaw and Hopkins (1955:16) list the known westward extent of range as Leon and Wakulla counties. AMNH 6933 from west of the Apalachicola drainage in Washington County, Florida, tends to substantiate Carr's record, which is not included on the distribution map.

_Specimens examined._--Total 144, as follows: FLORIDA: _Alachua_: UMMZ 64178, 100969; USNM 10545, 10704, "near" Gainesville; UMMZ 56599, Levy Lake. _Brevard_: AMNH 12878, Canaveral. _Broward_: UMMZ 109441, Hugh Taylor Birch State Park; USNM 109548, 22 mi. WNW, 6 mi. SSE Fort Lauderdale.

_Collier_: USNM 86828, Tamiami Trail, "near" Birdon. _Dade_: AMNH 50936, UMMZ 10183, 110981, Miami; USNM 84079, 86942, 15 mi. from (west) Miami, Tamiami Trail; UMMZ 111371, 19 mi. W, 1.3 mi. S Miami; UI 28984, 35 mi. W. (Miami) Tamiami Trail; AMNH 69932-33, UMMZ 101582, 101584, 104024, 40-45 mi. W Miami, Tamiami Trail. _Glades_: UMMZ 100836, mouth of Kissimmee River. _Hendry_: UMMZ 106302, 10.2 mi. SE Devil's Garden; UMMZ 106303-04, 106321-22, 30 mi. S Clewiston, near Devil's Garden.

_Hernando_: TU 13624, 0.5 mi. S Citrus Co. line on US Hwy. 19. _Highland_: AMNH 65537, 71618, Archbold Biol. Stat., Lake Placid; AMNH 65622, Hicoria.

_Hillsborough_: TU 13960, Hillsborough River, _ca._ 20 mi. NE Tampa; USNM 51184, Tampa; USNM 71156, Plant City. _Indian River_: USNM 55316, Vero Beach; USNM 59318, Sebastian. _Lake_: UMMZ 36072, USNM 20189, 029210, 029339, 38123, Eustis; UMMZ 76754-56, Lake Griffin. _Lee_: UMMZ 102276, 14 mi. SE Punta Gorda. _Leon_: CNHM 33701, USNM 95767, Lake Iamonia; USNM 103736, Silver Lake. _Marion_: AMNH 8294-95, UMMZ 95613 (4), USNM 52476-83, 100902-04, Eureka; AMNH 63642, near Salt Springs. _Martin_: TNHC 1292, 8.4 mi. N Port Mayaca. _Okeechobee_: AMNH 57379-84, Lake Okeechobee; AMNH 5931-32, Kissimmee Prairie. _Orange_: USNM 51421, 56805, Orlando; KU 16528. _Osceola_: USNM 029448, 029450-64, 029467-68, 029470, 029474-75, Kissimmee. _Palm Beach_: UMMZ 54101, Palm Beach; USNM 73199, Delray Beach. _Pinellas_: USNM 51417-20, St. Petersburg. _Polk_: AMNH 25543, Lakeland; UMMZ 112380, 6.7 mi. S Lake Wales; USNM 60496, 60532, 60534, 61083-87, Auburndale. _Putnam_: USNM 4373, 7651, Palatka; USNM 26035, ponds "near" Welaka. _Sarasota_: USNM 61352, Lake Myakka.

_Sumpter_: UMMZ 71791, Bushnell. _Volusia_: UMMZ 100673, Lake Helen.

_Washington_: AMNH 6933, Washington. _County unknown_: AMNH 4758; USNM 8899, St. John's River: USNM 59727-28, Lake Okeechobee, "near"

mouth Taylor's Creek; USNM 84080.

GEORGIA: _Baker_: SM 2083, USNM 029619, 38980-81, 70398, Mimsville.

_Berrien_: USNM 62217, Banks Mill Pond. _Charlton_: AMNH 69934, Okefinokee Swamp, SW Billy's Island; UMMZ 90010, east edge Okefinokee Swamp; USNM 84603, Okefinokee Swamp, Chesser's Island. _Irwin_: USNM 56804. _Lowndes_: UMMZ 67706, 10 mi. S Valdosta. _McIntosh_: USNM 19621, Darien.

SOUTH CAROLINA: _Charleston_: USNM 9670, Charleston.

NO DATA: AMNH 22750; USNM 71608-09.