• TABLE OF CONTENTS
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 Front Cover
 Introduction
 Taxonomic history of pseudemys...
 Intergroup relationships
 Discussion
 The question of nomenclature
 Conclusion
 Acknowledgement
 Literature cited
 Back Cover






Title: Taxonomic reappraisal of the turtle, Pseudemys alabamensis Bauer (FSM Bulletin)
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Title: Taxonomic reappraisal of the turtle, Pseudemys alabamensis Bauer (FSM Bulletin)
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Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Introduction
        Page 25
    Taxonomic history of pseudemys alabamensis
        Page 26
    Intergroup relationships
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
    Discussion
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
    The question of nomenclature
        Page 39
        Page 40
    Conclusion
        Page 41
    Acknowledgement
        Page 41
    Literature cited
        Page 42
    Back Cover
        Page 43
Full Text
BULLETIN
OF THE
FLORIDA STATE MUSEUM
BIOLOGICAL SCIENCES
olume 1 Number
A TAXONOMIC REAPPRAISAL OF THE
TURTLE PSEUDEMYS ALABAMENS/S BAUR
Archie Carr and John W. Crenshaw, Jr.
UNIVERSITY OF FLORIDA Gainesville 1957


The numbers of THE BULLETIN OF THE FLORIDA STATE MUSEUM, BIOLOGICAL SCIENCES, will be published at irregular intervals. Volumes will contain about 300 pages and will not necessarily be completed in any one calendar year.
William J. Riemer, Editor Roland F. Hussey, Associate Editor
All communications concerning purchase or exchange of the publication shoulc. be addressed to the Curator of Biological Sciences, Florida State Museum, Seaglc Building, Gainesville, Florida. Manuscripts should be sent to the Editor of the BULLETIN, Flint Hall, University of Florida, Gainesville, Florida.
Published 15 August, 1957
Price for this issue $30


A TAXONOMIC REAPPRAISAL OF THE TURTLE PSEUDEMYS A LA HA MEN SIS BAUR
Arch ik Carr and
John W. Crenshaw, Jr.1
During a recent study of certain sections of the emytlinc turtle genus Pscudemys, Crenshaw made a search for new characters that might be brought to bear on the question of relationships among the complexes in the southeastern United States. One aspect of the study led to a re-evaluation of the placement of Pscudemys alabamensis Jiaur in the synonymy of Pseudemys floridana mobilensis by Carr (1952). The present paper proposes that, in spite of the fact that all its characters occur individually with greater or lesser frequency in one stock or another of the P. floridana group, alabamensis may l)e a real genetic entity occupying a continuous small range in the Gulf drainage of the southeastern coastal plain. If so, its retention in synonymy can only lead to the ignoring of a zoogeographic situation which, though by no means well understood, appears to be of extraordinary interest.
Crenshaw was successful, as will be shown below, in finding at least one character that seems as good as, or better than, any hitherto used in defining the Pseudemys rubriventris group. A reassessment of alabamensis in the light of the new criterion brings out or re-emphasizes four salient facts: (1) The diagnosis of alabamensis. formerly weak, is strengthened. (2) The characters of alabamensis suggest P. nelsoni of peninsular Florida as the nearest relative. (3) P. alabamensis appears to form with nelsoni, and with rubriventris of the Atlantic coastal plain north of North Carolina, a species complex with a curiously discontinuous distributiona catena of stocks so closely knit that the gaps geographically separating the three forms seem incongruous. (4) P. alabamensis shares with nelsoni and rubriventris, and perhaps accentuates, a peculiar relationship with the floridana group, a section of the genus which, when judged by typical examples only, seems so divergent as to be of almost subgeneric level.
Archie Carr is Professor or Biological Sciences. I'niversiiy of Florida. Gainesville. He is the author of several books: among ihcm are Handbook of Turtles and C.uide to the Reptiles. Amphibians and fresh-water fishes of florida (with C. Coin). John Crenshaw. Jr. is Assistant Professor of Biology. Antioch College. Yellow Springs. Ohio. His doctoral dissertation is concerned with the genus Pseudemys in the southeastern I'nitcd Slates. He gratefully acknowledges the support of the Department of Zoology. University of Missouri, where he was employed during the preparation of this manuscript. Manuscript submitted I'.l August 1956.Ed,


Taxonomic History of Pseudemys alabamensis
Baur (1893:224) described alabamensis as a distinct species of the genus Pseudemys and noted that it was closely allied to rubriventris. He pointed out that the form had been treated by Agassiz (1857:433) under the name mobilensis. Baur designated syntypes (without catalogue numbers) in the collection of Mr. G. Kohn of New Orleans; these were deposited subsequently in the collection of the United States National Museum.
Siebenrock (1909:469) suppressed alabamensis to a synonym of rubriventris, but Stejneger and Barbour (1917:120) ignored his action and treated it as distinct. Carr (1938:106, 107), noting the almost concurrent ranges of alabamensis and the mobilensis-suwanniensis complex of the species floridana, and the agreement in coloration and conformation shown by "alabamensis" from various localities and the phase of floridana characteristic of those same localities, suggested that alabamensis might represent no more than an occasional variant of floridana. About the same time, Stejneger (1938:173), in clearing up certain errors of identification in the literature, referred to alabamensis as a subspecies of P. rubriventris; but subsequently he returned to his earlier opinion and treated alabamensis as a distinct species (Stejneger and Barbour, 1943:203). Carr (1952:280, 303) treated alabamensis as a synonym of P. floridana mobilensis for the reasons given above, and his treatment has been followed by subsequent workers.
Intercroup Relationships
Three more or less distinct groups of turtles of the genus Pseudemys occur in the territory under discussion: (1) the well-differentiated scripta group with no known morphologic overlap with either of the others; (2) the rubrivenlris group, composed of rubriventris, alabamensis, and nelsoni; and (3) the floridana group. Four forms meet in the territory occupied by alabamensis the coastal strip from the panhandle of Florida to New Orleans. The turtles of the floridana group, iii themselves zoogeographically puzzling, are dealt with by Carr in previous papers and most recently by Crenshaw in a detailed analysis now in manuscript form (Crenshaw, MS). The difficulties of interpreting relationships among the three major Floridian stocks, and among the many variant populations composing them, are bad enough when they are considered separately. Now, however, it appears necessary to evaluate them in the light of what appears to be


Taxonomic History of Pseudemys alabamensis
Baur (1893:224) described alabamensis as a distinct species of the genus Pseudemys and noted that it was closely allied to rubriventris. He pointed out that the form had been treated by Agassiz (1857:433) under the name mobilensis. Baur designated syntypes (without catalogue numbers) in the collection of Mr. G. Kohn of New Orleans; these were deposited subsequently in the collection of the United States National Museum.
Siebenrock (1909:469) suppressed alabamensis to a synonym of rubriventris, but Stejneger and Barbour (1917:120) ignored his action and treated it as distinct. Carr (1938:106, 107), noting the almost concurrent ranges of alabamensis and the mobilensis-suwanniensis complex of the species floridana, and the agreement in coloration and conformation shown by "alabamensis" from various localities and the phase of floridana characteristic of those same localities, suggested that alabamensis might represent no more than an occasional variant of floridana. About the same time, Stejneger (1938:173), in clearing up certain errors of identification in the literature, referred to alabamensis as a subspecies of P. rubriventris; but subsequently he returned to his earlier opinion and treated alabamensis as a distinct species (Stejneger and Barbour, 1943:203). Carr (1952:280, 303) treated alabamensis as a synonym of P. floridana mobilensis for the reasons given above, and his treatment has been followed by subsequent workers.
Intercroup Relationships
Three more or less distinct groups of turtles of the genus Pseudemys occur in the territory under discussion: (1) the well-differentiated scripta group with no known morphologic overlap with either of the others; (2) the rubrivenlris group, composed of rubriventris, alabamensis, and nelsoni; and (3) the floridana group. Four forms meet in the territory occupied by alabamensis the coastal strip from the panhandle of Florida to New Orleans. The turtles of the floridana group, iii themselves zoogeographically puzzling, are dealt with by Carr in previous papers and most recently by Crenshaw in a detailed analysis now in manuscript form (Crenshaw, MS). The difficulties of interpreting relationships among the three major Floridian stocks, and among the many variant populations composing them, are bad enough when they are considered separately. Now, however, it appears necessary to evaluate them in the light of what appears to be


rather widespread genie interchange, or at least genie community, with the rubriventris group. Crenshaw (M.S.) has traced out and evaluated several examples of character duplication as it bears upon the taxonomy of the floridana group; other aspects of their relationships, bearing upon the stains of P. alabamensis, must be examined here.
Figure I .Generalized distribution of three turtles of the genus Pseudemys, in peninsular Florida. P. /. peninsularis is not actually known to extend south of the broken line across southern Collier and northern Dade Counties.
Pseudemys nelsoni and the floridana croup.The range of P. nelsoni and the combined ranges of P. floridana peninsularis and I', f. suwanni-ensis are nearly coextensive (Tig. I), with even the ecologic position of nelsoni being apparently transgressed by the others. Because of this, one is at first inclined to view the markedly divergent appearance of adult nelsoni, of the "typical" phenotype, as the mark of a "good
411


species" in the conventional sense. It is therefore doubly surprising to find that in occasional specimens, and in some populations, the distinction between the tw-o groups weakens or breaks down completely.
While a number of characters have been used in differentiating between nelsoni and the floridana stocks, only two seem to be consistently diagnostic. These involve the conformation of the anterior face of the upper beak and a feature of the head pattern brought out for the first time by Crenshaw (MS).
In peninsularis and suivanniensis the tomium of the upper jaw is entire, anteriorly, whereas in nelsoni there is a prominent symphyseal notch accentuated by a toothlike cusp on each side (fig. 2). With respect to head markings, in all three forms a supratemporal stripe passes from the dorsolateral area of the neck, anteriorly across the temporal region, thence above and immediately adjacent to the eye, and out along the snout toward the external nares. This stripe is often obscure in large nelsoni. Another pair of prominent stripes, the paramedians, are situated between the supratemporals, one on each side of the median line. In nelsoni the paramedian stripes usually pass from the neck anteriorly across the occipital region to terminate abruptly posterior to the level of the eyes. In suwanniensis the paramedians typically continue anteriorly from the neck, running between the eyes to a point well out on the snout. Some specimens of peninsularis show the same pattern, but more often the paramedians pass anteriorly from the neck to a point posterior to the eye where each bends laterally to join, or almost join, the adjacent supratemporal. Unfortunately, both of the above characters may break down in very young nelsoni which may exhibit both a smooth upper tomium and a head-stripe pattern typical of suwanniensis. The reduction of head striping characteristic of nelsoni seems to be correlated with increase in size, and it is possible that notch and cusp development may also be ontogenetic, although this has not been demonstrated.
Two additional characters now appear to be consistently useful in defining nelsoni. In suwanniensis and peninsularis the supratemporal head stripes either do not join anteriorly or the junction is faint and the stripes pass through or immediately adjacent to the nostrils (fig. 2). In nelsoni the supratemporals pass forward from the eye and join conspicuously well above and posterior to the external nares. A sagittal stripe passing anteriorly from between the eyes usually joins the supratemporal stripes at their confluence to form a prefrontal arrow-shaped figure (fig. 2). Of 79 specimens of nelsoni examined, only 11, all medium-sized or large specimens, had cne or more breaks in the prefrontal arrow. The pattern was suggested in every instance.


To determine applicability of the character, a total of 45 P. rubriventris from Virginia, West Virginia, and New Jersey were examined. All of these individuals had a prefrontal arrow except five in which it was replaced by a prefrontal transverse stripe. Another had a
P. F. SUWANNIENSIS P. F. PENINSULARIS P. NELSONI
Jaw Conformation
Head Striping
Second Lateral Lamina
Figure 2.Comparison of three Florida turtles of the genus Pseudemys with respect to upper jaw conformation, head striping, and color pattern of the second lateral lamina (left side).
slight break in the arrow pattern, and three with generally obscured head markings exhibited very faint arrows. Apparently, the prefrontal arrow is characteristic of the rubriventris group, and absent in the floridana complex. The prefrontal arrow is found also in the Pseudemys scripla group, but its frequency has not been studied.
The other character found to contribute toward intergroup diagnosis involves the color pattern of the second lateral (or "costal")


lamina ol the carapace. It is primarily of aid in the separating of nelsoni and suwanniensis, but also distinguishes between some specimens of nelsoni and peninsularis. In the last two forms the basic-pattern of the second lateral consists of a prominent, centrally located, light, transverse (vertical) stripe or band (fig. 2). This light band passes from the ventral (lateral) edge of the scale toward the apex of the dorsal (medial) edge. Just short of the apex it usually bends sharply posteriad and passes to the posterodorsal edge of the lamina. There may be another branch passing posteriad from the anterodorsal edge of the lateral lamina to join, or almost join, the posterior arm of the main transverse stripe, thus forming a Y-shaped figure. Rare variations include transverse bands which pass dorsad (mesiad) through the apex, or stop abruptly just short thereof without bending. In peninsularis there are usually two to six narrow, transverse stripes paralleling the central band; in adult nelsoni such accessory stripes are often lacking and, even if present, are faint and few in number. Juvenile nelsoni usually exhibit a number of accessory stripes which apparently fade with age.
In suwanniensis the basic pattern of the second lateral lamina is different from that of both nelsoni and peninsularis. As in the last two, a central, transverse light stripe may pass dorsad from the ventral (lateral) edge of the lateral lamina, bend posteriad short of the apex, and thence run to the posterodorsal edge (fig. 2). More important, a longitudinal stripe passes from the middle of the median stripe to the posterior edge of the lamina. The C-shaped figure thus formed by the upper half of the median stripe and the two horizontal stripesone from the middle of the median stripe; one from the upper endis virtually always present in suwanniensis. The lower half of the median stripe may be lacking, and other stripes may or may not pass from the outer bend of the C-shaped figure to any edge of the lateral lamina. Concentric light circles are often present within the C-shaped figure.
Thus, there are lour characters which may be employed in differentiating among these three forms. Two of these, the prefrontal arrow and the notch and cusps of the upper jaw, are characteristic of nelsoni but rarely present in peninsularis and suwanniensis. A third character, the color pattern of the second lateral lamina, is of primary importance in recognizing suwanniensis, but is also of some value in distinguishing between nelsoni and peninsularis. Finally, although the head stripe patterns of all three forms differ on the whole, the pattern usually found in suwanniensis occurs too frequently in the other two to be of much help in the determination of that


form. However, the head stripe patterns described for peninsularis and nelsoni occur but rarely in other forms and accordingly are of some diagnostic value.
Another feature of particular use in differentiating between sii-wanniensis and peninsularis, is the more or less symmetrical and extensive pattern of dark markings always evident on the plastron of suwanniensis. In peninsularis dark plastral markings are usually lacking, and even when present they are rarely symmetrical and never extensive. While nelsoni may exhibit an immaculate plastron like peninsularis, or approach suwanniensis in regard to distribution of plastral markings, it typically lies somewhere between the two. Its plastral markings are usually markedly asymmetrical and not so extensive as in suwanniensis.
Relationships of Pseudemys alabamensis.At the time Carr proposed relegating alabamensis to synonymy, his acquaintance with cusp-jawed Pseudemys from eastern Gulf drainages had involved six live individuals from New Orleans shown him by Percy Viosca; two live topotypes from Mobile in a lot of a dozen "Mobilians"a local name for P. f. mobilensis plus P. alabamensis plus a half dozen topotypes, including the type (fig. 3), in the collections of various museums; and two hatchlings "from brackish water" at Crystal River on the Gulf Coast of Citrus County, Florida. The point that stands out in Can's notes is that, except that they all had notched jaws, the "alabamensis" at New Orleans looked strikingly like the local version of the P. floridana group (P. vioscana Brimley); those at Mobile resembled mobilensis: and the Crystal River animals seemed suspiciously similar to suwanniensis. When these observations were made, Carr knew nothing of the character proposed by Crenshawthe oblique prefrontal stripes joining anteriorly to form, with the sagittal stripe, the prefrontal arrow. Moreover, a re-examination of the little Crystal River specimens (UF 1736) shows that they may well be the young of typical P. nelsoni. Besides this material Carr had seen another specimen, the evaluation of which, even in the light of: the resurrection of alabamensis, remains a puzzle. A most surprising occurrence of the alabamensis phenotype is seen in an individual (ANSP 4521) from "Wolf River, Shelby County, Tennessee": no other example of a notch-jawed Pseudemys can be found from anywhere near this region. This unique specimenmore recently examined by Crenshaw and found to show the alabamensis head patterncontributed toward the rationale on which Carr based his earlier decision to suppress alabamensis as some sort of spurious phenotype.


Figure 3.Dorsal and ventral views of the holotype of Pseudemys alabamensis (USNM 209<>(>) photographed prior to the


removal of the head. Note the dark plastral vermiculations which arc also characteristic of adult males of hoth ntbrwentrU and nelsoni.


Crenshaw has recently re-examined the holotype (USNM 20966), the only paratype (USNM 20967), 6 topotypes (USNM 55501 and 55786; MCZ 1660-1663) and 2 Floridian specimens of alabamensisone from near Apalachicola (USNM 101090) and one from Wakulla Springs, Wakulla County (Crenshaw collection 1019-1). The skin of the heads of the holotype and paratype is now lacking, but in all the other specimens the prefrontal arrow is evident, while in all specimens of P. f. floridana and P. f. mobilensis, which are, respectively, the eco-geographical vicariahts of peninsularis and suwanniensis, the prefrontal arrow is lacking. Moreover, the pattern of the second lateral in all specimens of alabamensis was basically like that of nelsoni and different from that of mobilensis (which is identical with that of suwanniensis). The subspecies P. f. floridana, which also occurs in the Mobile Bay area, is like peninsularis with respect to all the characters described above except that the pattern of the supratemporal and paramedian head stripes is like that of suwanniensis. The basic color pattern of the second lateral lamina of floridana is thus similar to that of alabamensis. Differences in the color patterns of the lateral laminae of the Mobile Bay examples of alabamensis and floridana are evident but are not so pronounced in preserved material as in fresh material. Table 1 summarizes some of the diagnostic characters for the six forms discussed above.
Discussion
It appears unwarrantable to withhold taxonomic recognition from alabamensis. If there actually is such a form, the criteria at hand draw it readily into the rubriventris group and name as its nearest ally Pseudemys nelsoni of the Floridian peninsula. The only character known to distinguish consistently between the two is the section of the head pattern described above. In nelsoni the paramedian stripes end back of the eyes (fig. 2), but in alabamensis they continue anteriorly between the eyes and onto the snout as in suwanniensis.
Reasoning from the facts thus far presented, a fairly familiar zoo-geographic design emerges. If intergradation between the northern Gulf coast alabamensis and the peninsular Florida nelsoni were established, and if the gaps separating the ranges of these forms from that of rubriventristhe coastal plain of the northeastern United Stateswere partially filled in, the characters common to the three would be taken as evidence that they are a formenkreis with geographic discontinuities due to incomplete collecting or to recent extinction at the hand of man.


TABLE 1.
Summary of some characters of southeastern representatives of Pseudemys alabamensis, nelsoni, and floridana.
alabamensis 5 f. floridana f. peninsularis f. mobilensis f. suwanniensis
Inhabits "panhandle" of western Florida + + 4-
Inhabits peninsular Florida + + +
Notch and cusps on upper jaw + +
Prefrontal arrow 4- +
C-shaped figure on second lateral laminae + +
Dark plastral marks + or + or + +
Supratemporal and paramedian head stripes arc: Parallel, not reduced 4- rare 4- occas. +
Parallel, paramedians reduced occas. +
Joined posterior to eyes occas. +
In 1942 Carr called attention to concurrence in geographic variation between rubriventris populations and those of the floridana group. Recent work by Crenshaw has turned up additional evidence of phenotypic duplication and suggests that the parallelism should not be attributed to independent genes similarly selected, but may be based on actual kinship.
The reason such an explanation is hard to accept is the fact that


the two groups occupy the same territory and the same series of habitats, and the thought of their being intei fertile or even being as closely related as the consonance would imply goes against accepted logic. We realize oi course that barriers can be unseen as well as seen; but even so, it is not easy to visualize a relationship that allows two species to show so much evidence of genie interchange and still retain modal integrity in a common habitat. The distribution of characters within the ftoridana group alone is complex enough, with its multidirectional clines, its array of slightly differentiated stocks isolated to varying degrees by barriers both ecologic and geographic, and intergrading in some places but remaining sympatrically discrete or vicariating without intergradation elsewhere. But when phenotypic overlapping with the rubriventris group is added to this picture, the contusion of variables acquires a third dimension, and it becomes even more difficult to piece together the zoogeographic history of the animals.
A good place to illustrate this problem is in the Apalachicola drainage of western Florida. There are two forms of the ftoridana group in this area. One of these is the local version of the mobilensis-to-suwanniensis cline; and the other is close to what is known as P. /. ftoridana. The relationship between the two seems to conform to the pattern for the complex, of which a chief feature is the intergrading of "subspecies" in some sections of their adjacent ranges and their remaining disjunct in others. In the Apalachicola Valley a complicating element is superimposed on this pattern when one sees in the ftoridana population an emergence of what seems a strong tendency toward the characters of Pseudemys nelsoni of the rubriventris group.
We have four young specimens (UF 440-443) from "between Scotts Ferry and Blountstown," immediately to the north of the known range of alabaniensis (taken by a collector in the employ of Ross Allen and presented to us by Wilfred Neill) that are indistinguishable, by any characters known to us, from nelsoni of the peninsula. The agreement is so close that it was hard to believe that a mistake had not been made in assigning the data. Conversation with Neill and Allen corroborate the locality however. Moreover, the small number of other specimens in hand from the area and the huge series of live specimens casually examined at the Ross Allen Reptile Institute of Silver Springs, Florida show decided tendencies toward nelsoni and connect the four young specimens witli the average of the local ftoridana stock in all respects except lor the notched jaw:s and prefrontal arrows of the former, in spite of its similarity to nelsoni, the ftoridana population is consistently smooth jawed. In this character and in the joining of the clear-cut prefrontal stripes, all four of


ihe little turtles, as implied above, agree more closely with nelsoni than with the nelsoni-\ike floridana stock in their own area. The hatchlings may then be (I) real P. nelsoni from nelsoni parents, which would extend the range of that species northwestward some 150 miles,
(2) variants from the modal condition of the local alabamensis or floridana stock resulting from chance mutation or recombination, or
(3) representatives of a deme of the local alabamensis or floridana stock that our inadequate sampling from the area has not otherwise turned up.
In any event, consonance of the specimens with the local trend is interesting, and they call attention to the fact that Apalachicolan floridana are like nelsoni in the following ways:
(1) Lack of a reticulate pattern with dominant C-shaped marks on the lateral laminae.
(2) Emphasis of a vertical light band across each lateral, with obsolescence of other light markings on the laterals.
(3) Deepening of the dark ground color of the carapace to nearly black.
(4) Variability in plastral markings, with achdt specimens most often unmarked below.
(5) Occurrence of intensely pigmented smudges on only a few inframarginal seams instead of rings or ocellated spots on most or all of the seams.
(6) Abrtipt termination of the paramedian head stripe behind the eye with reduction of head pattern generally.
(7) Erythrism of the lower shell.
The most extraordinary implication of this situationwith or without reinforcement by the four questionable hatchlingsis that floridana of the Apalachicola drainage, and indeed all floridana populations, are probably genetically much closer to the rubriventris group than any previous study has indicated. There is, in fact, no known character of the rubriventris group that fails to turn up somewhere, in the floridana complex. As an example of the sort of detailed "give-and-take" that occurs, the color pattern of the marginal laminae may be offered.
The upper marginal pattern of nelsoni comprises three extremely different sets of markings, as follows: (1) a predominantly ocellate pattern involving a C-shaped figure with the open side directed posteriorly and enclosing a light spot, an inverted L-shaped figure anterior to this, and a broad stripe along the lower edge of the lamina; (2) a pattern composed of three centrally located longitudinal stripes parallel to the same broad stripe involved in the preceding and thus


made up entirely of longitudinally oriented lines; and (3) a single conspicuous median vertical light band running from the marginal stripe toward or to the upper angle of the lamina and separating it into two fields that may be unmarked or with scattered irregular markings.
Selected typical examples of these three styles of patterns show great divergence indeedmuch stronger, for instance, than the diagnostic divergence of many named races. And yet all three occur in sets of nelsoni siblings (e.g., UF 1168, six hatchlings from Lake County, Florida) in both typical form and in every possible intermediate combination; some specimens have all marginals marked with one or another of the patterns, while in others there is bilateral or anteroposterior replacement of one pattern by another.
This range of variation involves such marked differences and such complicated intergradations that it is astonishing to find, on top of all the other parallelisms, that in the area between northwestern Marion County and the base of the panhandle, ftoridana populations often show precisely the same spread in pattern type. When this coincidence in seemingly irrelevant and nonadaptive features is added to the examples of intergroup concurrence in variation already known it becomes increasingly difficult to see how the hidden isolating factors in these two sympatric stocks could possibly be operating to maintain the measure of disjunction that exists.
Although the present study has not included the extensive reappraising of material outside the southeast, certain known features of extra-Floridian sections of the ftoridana group clearly bear on the problem of character-sharing by this and the rubriventris group. Even the notch-and-cuspthe most trenchant distinctive feature of the rubriventris groupis diagnostic also of the westernmost representative of the species ftoridana. viz., P. f. texana of western Texas and adjacent parts of Mexico. The fact that this race actually represents the geographic and morphologic extreme among ftoridana turtles can be seen in the clinal nature of annectent hoyi, which has, not notched and cusped, but emarginate upper jaws. It has not been pointed out elsewhere that another conspicuous feature of texanaz tendency for one of the lateral head stripes to break up and reorient its tympanal segment to form a conspicuous spot or vertical band through the ear can be seen in both notched- and smooth-jawed turtles from coastal Louisiana and .Alabama (e.g., MCZ 1659).
Yet another character, of unknown significance, but involved in the problem, is the peculiar "marbled shell"carapace and plastron evenly mottled by the disrupted and completely redistributed pattern


of pigmentationfound not only in a small percentage of rubriventris and nelsoni but also in the holotype of alabamensis. While no marbled specimen of floridana is now at hand, Carr has seen the tendency among turtles being hauled away from Lakes famonia and Jackson, Leon County, Florida, when they have gone dry in years past; and the late Leonhard Stejneger told him of having seen it in material sent by a collector from the same localities. Carr has recently reexamined two of these specimens (USNM 957fi5-7fi6). Both seem to him intermediate between nelsoni and floridana. One (95765) even has a notched upper jaw, although no cusps are present. The prefrontal arrow is lacking.
The Question of Nomenclature
ff Pseudemys nelsoni ranges northwestward into the Apalachicola area (fig. 4) as a discrete genetic entity, then one might attribute the
Figure 4.Distribution of Pseudemys alabamensis and P. nelsoni.
nelsoni-like traits in the floridana populations there to occasional hybridization, or, as Crenshaw (MS.) proposes for similar populations elsewhere, to introgressive evolution. Moreover, if the notch-jawed Mobilians (alabamensis) ranging eastward to the Apalachicola area and slightly beyond likewise represent a separate form and not just an irregularity in the floridana matrix, and if alabamensis is, as it


seems, of rubriventris "blood," then one might conclude that alabamensis and nelsoni are a single varying species with an apparent distributional problem due merely to inadequate sampling. With the same line of reasoning the closely similar, but geographically separate, rubriventris falls into the design. A conventional nomenclatural picture of this situation would be shown by trinomial listing of the three, with the specific name derived from LeConte's P. rubriventris, which has priority.
But the situation is not quite so simple when the detail of our evidence is considered. With respect to the relationships of the northeastern rubriventris to the other two forms, we know only that they are separated by an apparent broad hiatus across the states of Georgia, .South Carolina, and North Carolina. We have not studied the morphological variation in rubriventris quantitatively and cannot state with any assurance that it is, or is not, genetically distinct. In view of the frequency with which interspecies reproductive barriers are transgressed in nature within the genus Pseudemys, we do not feel that probability of biological reproductive isolation is a criterion of usefulness in the present situation.
The relationship of nelsoni to alabamensis is not nearly so clear as it might be. From the "panhandle" of western Florida, lying between the principal ranges of alabamensis and nelsoni, we have a sample of six specimens, all with reliable collection data (fig. 4). Two of these specimens, both taken near the coast but from different localities, are typical of adult alabamensis. The other four, taken from a single-locality some distance inland and north of the coast, are equally typical of juvenile nelsoni.
Our small and manifestly inadequate sample suggests that alabamensis and nelsoni overlap geographically in the Apalachicola area, behaving as perfectly good species, perhaps by virtue of microgeo-graphic or ecological isolation. In view of the single known character difference between the forms, it seems possible that we have sampled an intergrading population and that chance alone has determined that our four specimens from one locality be unlike the two available from other localities.
When a trinomial is used, if it means anything at all, it means that a situation has been pretty well worked out, is understood, and is nothing to worry about any more. It should give grounds for a sense of security that in the present case would be wholly uncalled for. Looking only at rubriventris turtles, the move might be logical in spite of the geographic gap. Appraised against the background of the extra-rubriventris relations of the notch-jawed stocks, the situation seems


to call for a more noncommittal disposition. After some bickering between ourselves, therefore, we propose to eschew the trinomial-ol-complacency and reinstate the notch-jawed Mobilian under a binomial-of-reserved-judgment, Pseudemys alabamensis Baur.
Conclusions
In the light of new criteria we propose the rehabilitation of Pseudemys alabamensis as a member of the turtle fauna of coastal areas of Alabama, Louisiana, and northwestern Florida, and perhaps ol eastern Texas. Through one contiguous or syinpatric relative or another, alabamensis appears to intergrade with stocks of both the rubriventris and the floridana groups. It may be that the much deplored morphological overlap of these turtles, which have confused naturalists for more than a hundred years, can best be exemplified by, and may eventually be largely explained through, study of the "alabamensis" phenomenon, which, whether a "good species," a sporadic variant, or merely a clumping of endpoints in several geo- and ecoclines, is bound to repay any attention given it.
Acknowledgments
For assistance in a number of ways, and for permission to examine specimens in their private collections or in their care, we are grateful to the following: L. N. Bell, University of Miami, Florida; Charles Bogert, American Museum of Natural History (AMNH); Doris Cochran, United States National Museum (USNM); Roger Conant, Philadelphia Zoological Gardens; J. C. Dickinson, University of Florida Collections (UF); Arthur Loveridge, Museum of Comparative Zoology (MCZ); Neil Richmond, Carnegie Museum; Jay Savage, Academy of Natural Sciences, Philadelphia (ANSP); and Albert Schwartz, Charleston Museum. To save space we have not listed the location and catalogue numbers of specimens examined, except in the case of alabamensis and of other material which seemed critical or possibly controversial. It may be of help to future workers to note that series of nelsoni are available in the Carnegie Museum, the Charleston Museum, and the University of Florida Collections. Most of the rubriventris material examined is from the Carnegie Museum, the Museum of Comparative Zoology, the Philadelphia Academy, and the private collection of Roger Conant.
A considerable number of people have helped in collecting, have provided specimens, suggestions, criticism, or varied abettance. To all of these we are deeply grateful. We are especially obligated to


to call for a more noncommittal disposition. After some bickering between ourselves, therefore, we propose to eschew the trinomial-ol-complacency and reinstate the notch-jawed Mobilian under a binomial-of-reserved-judgment, Pseudemys alabamensis Baur.
Conclusions
In the light of new criteria we propose the rehabilitation of Pseudemys alabamensis as a member of the turtle fauna of coastal areas of Alabama, Louisiana, and northwestern Florida, and perhaps ol eastern Texas. Through one contiguous or syinpatric relative or another, alabamensis appears to intergrade with stocks of both the rubriventris and the floridana groups. It may be that the much deplored morphological overlap of these turtles, which have confused naturalists for more than a hundred years, can best be exemplified by, and may eventually be largely explained through, study of the "alabamensis" phenomenon, which, whether a "good species," a sporadic variant, or merely a clumping of endpoints in several geo- and ecoclines, is bound to repay any attention given it.
Acknowledgments
For assistance in a number of ways, and for permission to examine specimens in their private collections or in their care, we are grateful to the following: L. N. Bell, University of Miami, Florida; Charles Bogert, American Museum of Natural History (AMNH); Doris Cochran, United States National Museum (USNM); Roger Conant, Philadelphia Zoological Gardens; J. C. Dickinson, University of Florida Collections (UF); Arthur Loveridge, Museum of Comparative Zoology (MCZ); Neil Richmond, Carnegie Museum; Jay Savage, Academy of Natural Sciences, Philadelphia (ANSP); and Albert Schwartz, Charleston Museum. To save space we have not listed the location and catalogue numbers of specimens examined, except in the case of alabamensis and of other material which seemed critical or possibly controversial. It may be of help to future workers to note that series of nelsoni are available in the Carnegie Museum, the Charleston Museum, and the University of Florida Collections. Most of the rubriventris material examined is from the Carnegie Museum, the Museum of Comparative Zoology, the Philadelphia Academy, and the private collection of Roger Conant.
A considerable number of people have helped in collecting, have provided specimens, suggestions, criticism, or varied abettance. To all of these we are deeply grateful. We are especially obligated to


42
Bt I.I.I I IN FLORIDA STATE MUSEUM
Vol. 2
Claude Adams, Walter Aultenberg, Fred Berry, David Caldwell, J. C. Dickinson, Coleman Coin, Arnold Grobman, Keith Hansen, Robert Hellman, Richard Higluon, William Jennings, David Karraker, [ohn Kilby, Ellis Lanquist, Ann Lyons, Larry Ogren, Beth Schultz, and C. H. Wharton, all, now or formerly, of the University of Florida: to Lewis Marchand, Gainesville, Florida; to Albert Schwartz, Charleston Museum; to L. H. Babbitt, Petersham, Massachusetts: to Ernest Williams, Museum of Comparative Zoology; to Roger Conant, Philadelphia Zoological Gardens; and to William Duellman, University of Michigan.
Literature Cited
Ar.Assrz. Lor is
1857. Contributions to the natural history of the United Slates. Vol. I. Boston: Little. Blown and Company, li + 152 pp.
Bai r. g.
1893. Notes on the classification and taxonomy of the Tcstudinata. Proc. Amer. Phil. Soc., vol. 31, pp. 210-225. Carr, Archie F.
11(38. A new subspecies of Pseudemys lloridana, with notes on the floridana complex. Copeia, no. 3, pp. 105-109.
15)42. The stains ol Pseudemys floridana lexana, with notes on parallelism in Pseudemys. Proc. New England Zool. Club, vol. I. pp. 69-76.
1952. Handbook of Turtles. Ithaca, N. V.: Coinstock Publishing Associates, xv 4-542 pp., 37 lig., 82 pis., 23 maps. Crenshaw, John VV.. |k.
MS. The ecological geography of the Pseudrmxs floridann complex in the southeastern United States. Unpublished dissertation, Univ. Florida.
SlEBENROCK, F.
1909. Synopsis der rezentcn Schilclkrotcn. Zool. Jahrb., Suppl., vol. 10. pp. -ILJT-iilS. Stejnecer, Leonhard
1938. Restitution of ihc name Plychemys lioxi Agassi/ for a western river tortoise. I'roc. Biol. Sot. Washington, vol. 51, pp. 173-176. Stejnecer, Leonhard and Thomas Barroi r
1917. A check list of North American amphibians and reptiles. First edition.
Cambridge, Massachusetts: Harvard University Press, iv + 125 pp. 1943. A check list of North American amphibians and reptiles. Fifth edition. Cambridge, Massachusetts: Harvard University Press, xix + 200 pp.



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