7 p. : ill. ; 24 cm.Includes bibliographical references (p. 6-7)

Dowling, Herndon G. (Herndon Glenn), 1921-

American Museum of Natural History Scientific Publications

i1AFieuican%MllsdumPUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORYCENTRAL PARK WEST AT 79TH STREET, NEW YORK 24, N.Y.NUMBER 1948 JUNE 17, 1959Apical Papillae on the Hemipenes of TwoColubrid SnakesBY HERNDON G. DOWLING'Edward D. Cope first proposed the use of characters of the reptilianhemipenis for taxonomic work in his "Prodromus of a new system ofnonvenomous snakes" (1893). In this paper he mentioned four speciesof snakes, Oligodon subquadratus, Cynophis helenae, Tropidocloniumlineatum, and Ceratophallus vittatus, that had rigid papillae or anawn at the apex of the hemipenis. The hemipenis was figured for thesespecies in Cope's later works (1895, 1900), and the terminal append-ages appeared to be of two distinct types. Oligodon, Tropidoclonium,and Ceratophallus had a pair of rounded papillae, while Cynophis hada single, spiral pointed structure.I have recently had the opportunity of examining the hemipenes ofTropidoclonium (_ Tropidoclonion) lineatum and Cynophis (-Elaphe) helenae. Cope's descriptions are found to be essentially correctin one case, but quite erroneous in the other.Tropidoclonion lineatum HallowellThe hemipenis of this snake is of particular interest, because thestatus of the monotypic genus Tropidoclonion Cope (1860) has beenquestioned repeatedly. Superficially Tropidoclonion is much likeThamnophis Fitzinger (1843). Dunn (1932) evaluated the various fea-tures on which Tropidoclonion was based and stated (p. 196), "I ...suggest that the snake in question be known henceforth as Thamnophis1 Research Associate, Department of Amphibians and Reptiles, the American Mu-seum of Natural History; Associate Professor of Zoology, University of Arkansas,Fayetteville.AMERICAN MUSEUM NOVITATES'\JJIlID A \V7" BFIG. 1. Hemipenis of Tropidoclonion lineatum Hallowell. A. "Tropidoclo-nium lineatum Hallow., Texas. X4," as figured by Cope (1895, pl. 22, fig. 12)from an inverted specimen that had been split along the median line andspread flat. B. Drawing of the right hemipenis, everted, from a specimen inthe Dowling collection.lineatus." This was opposed by other workers, however, as "the mono-typic form is obviously more different from any species of Thamnophisthan any of the species in that genus are from one another" (Stejnegerand Barbour, 1933, p. vi). Actually only the unusual ornamentation ofthe hemipenis would lead to such a decision.Recently Dr. Albert P. Blair sent a series of these snakes to me alive,and I had the opportunity of preparing some of the hemipenes aseverted specimens. I am able to corroborate Cope's observation of theapical papillae, but in the everted organ (fig. IB) the papillae appearconsiderably different from those of the dissected organ figured byCope (fig. IA). It may be seen also that the "longitudinally plicate"area shown near the distal end of Cope's figure is actually an unorna-mented region that expands greatly; the "plicae" are merely folds.DESCRIPTION OF HEMIPENIS: The hemipenis of Tropidoclonion isa single, non-capitate organ with a length of about 12 subcaudals (tothe base of the papillae). It is somewhat bilobed distally and has thelateral edges of the lobes extended into long papillae. The sulcus issingle and extends directly from the proximal towards the distal endbetween the lobes, but does not reach the apex. Its lips are neitherraised nor especially ornamented. The proximal half of the organ isornamented with spines: about four large spines basally and numerousrows of much smaller spinules towards the distal end. There is a dis-tinct line of demarcation between this spinose area and the bare distalhalf, which is unornamented except for the two lateral papillae.2 NO. 1948DOWLING: PAPILLAEThe hemipenis of Tropidoclonion, therefore, is "natricine" in itsbasic features: the presence of a single sulcus and ornamented withspines without calyces. Nevertheless, it differs from that of all otherknown American genera in the possession of a pair of elongate apicalpapillae. Although these papillae appear to be merely hollow exten-sions of the lobes found in many species of Natrix and Thamnophis,no other American snake is known to approach the state shown byTropidoclonion. Its present status as a monotypic genus would seemto be assured until some such indication of relationship with otherspecies is found.It is of considerable interest, therefore, that Cope, in his originalwork on hemipenes (1893, p. 483), established a new genus, Cera-tophallus, for the Oriental natricine, Tropidonotus (= Natrix) vittatusLinnaeus, "on account of the presence of a rigid papilla on the apexof each branch of the hemipenis." While no close relationship ofTropidoclonion with this species is suggested here, as N. vittatus has adivided hemipenis with forked sulcus (vide Cope, 1895, pl. 23, fig. 11),it is notable that at least one other "natricine" snake possesses the apicalpapillae.Elaphe helena DaudinCope pointed out the presence of an apical papilla on the hemipenisof "Cynophis" in his first paper on the characteristics of the hemipenes(1893, p. 481). The figure published later (1895, pl. 16, fig. 6) shows anextraordinary, single, spiral awn of a type not otherwise describedamong reptiles (fig. 2A). However, he stated (1895, pp. 202-203), "InCynophis I have found a remarkable apical awn, but as I have had theopportunity of examining but one individual, I am not sure how con-stant it is." Nevertheless, he used this character as an important featurein his synopsis of genera (1895, p. 205).Malcolm Smith (1943, p. 149) described the hemipenis of Elaphehelena, as he did for the other Indian snakes. His omission of any refer-ence to an apical structure might be taken to indicate its absence. How-ever, he did not refer to Cope's work, nor did he figure the hemipenisof this species. Thus the question as to the constancy of this characterhas remained open from the time that Cope first proposed it.A recent visit to the United States National Museum has allowed meto examine the hemipenes of a specimen from Ceylon (U.S.N.M. No.129738) in that collection.DESCRIPTION OF HEMIPENIS: The hemipenis of Elaphe helena is asingle, non-capitate organ that is 25 subcaudals in length and possesses1959 3AMERICAN MUSEUM NOVITATESAFIG. 2. Hemipenis of Elaphe helenae Daudin. A. "Cynophis helenae Daud.,Ceylon. X 3," as figured by Cope (1895, pl. 16, fig. 6) from an inverted speci-men that had been split along the median line and spread flat (slightly re-duced). B. Drawing of the right hemipenis of U.S.N.M. No. 129738, whichwas prepared in the same fashion.4 NO. 1948DOWLING: PAPILLAEa single sulcus (fig. 2B). The proximal two-thirds of the organ is un-ornamented, except for three rows of elongate spines that degenerateinto irregular groups of smaller spines near the base. One of thespinous rows lies along the sulcus on each side; the third row is on theside opposite the sulcus. At the level of subcaudal XIV these spines areabruptly replaced by minute spinules that are connected in one direc-tion by membranous folds that extend distally and away from thesulcus in a roughly pinnate fashion. Much lower and less distinct foldsconnect the spinules in the other direction to form large and poorlydifferentiated calyces that extend to the distal end of the organ. Thelips of the sulcus are unornamented proximally, but are beset withnumerous spinulose papillae distally. There is no apical awn or struc-ture of any kind. As this description (as well as Cope's) is taken froman inverted hemipenis that has been split and spread out, no precisedescription of the shape can be made. However, the absence of exten-sive folding in the distal portion suggests that there are no distal lobes.These observations suggest that Cope unintentionally included astrand of the retractor muscle or some other artifact in the publishedfigure and that a spiral apical awn does not exist on the hemipenis ofElaphe helena or that of any other known reptile.Nevertheless, the hemipenis of Elaphe helena does differ to a con-siderable degree from that of the genotype, Elaphe quatuorlineataLacepede, and that of the American and European species currentlyallocated to that genus (vide Dowling, 1958, p. 36, pl. 1). It also differsin having an entire anal plate rather than the divided one character-istic of Nearctic and Palearctic species. However, its dorsal scales arereduced as:6+7 5+6 4+525 23 21 196+7 5+6 4+5and thus show the midlateral mode of reduction possessed by otherspecies currently allocated to Elaphe.Because the amount of interspecific variation is still unknown inthose characters in which it differs from the genotype, and its knowncharacteristics do not suggest allocation to any other presently recog-nized genus, it seems preferable to retain helena within the genusElaphe for the present. At some future time, when the interspecific andintergeneric variation of the hemipenial and scutellational charactersis known and when other morphological features may be taken intoconsideration, some different decision may be necessary. Certainly it1959 5AMERICAN MUSEUM NOVITATESdiffers from most of the species of Elaphe in numerous ways. With nomore information than is presently available, however, a change in itsgeneric status would do no more than to substitute one indefinite situa-tion for another.ACKNOWLEDGMENTSI wish to thank Dr. Albert P. Blair, University of Tulsa, and his as-sociates Dr. Ralph Kelting and Mr. Paul Buck, for their rapid responseto my request, for living specimens of Tropidoclonion. I also wish tothank Dr. Doris M. Cochran, Curator of Reptiles, United States Na-tional Museum, for her warm hospitality and for allowing me to makethe observations on Elaphe helena reported here. I continue to be in-debted to Dr. Guerdon D. Nichols, Dean of the College of Arts andSciences, University of Arkansas, and to the National Science Founda-tion (N.S.F.-G4443) for the financial support that allowed my visit tothe United States National Museum.The original drawings of the hemipenes were made by Frances W.Gibson, of the Department of Zoology, University of Arkansas.LITERATURE CITEDCOPE, EDWARD D.1860. Catalogue of Colubridae in the museum of the Academy of NaturalSciences of Philadelphia. I. Calamarinae. Proc. Acad. Nat. Sci. Phila-delphia, vol. 12, pp. 74-79.1893. Prodromus of a new system of the non-venomous snakes. Amer. Nat.,vol. 27, pp. 477-483.1895. The classification of the Ophidia. Trans. Amer. Phil. Soc., new ser.,vol. 18, pt. 2, art. 3, pp. 186-219, pls. 14-33.1900. The crocodilians, lizards, and snakes of North America. Rept. U. S.Natl. Mus., for 1898, pp. 153-1294, pls. 1-36.DOWLING, HERNDON G.1958. A taxonomic study of the ratsnake. VI. Validation of the generaGonyosoma Wagler and Elaphe Fitzinger. Copeia, 1958, no. 1, pp.29-40, figs. 1-3, pl. 1.DUNN, EMMETr R.1932. The status of Tropidoclonion lineatum. Proc. Biol. Soc. Washing-ton, vol. 45, pp. 195-198.FITZINGER, LEOPOLD J. F. J.1843. Systema reptilium. Fasciculus primus: Amblyglossae. Vienna, Brau-muller et Seidel Bibliopolas, 106+vi+[3] pp.SMrMH, MALCOLM A.1943. The fauna of British India, Ceylon and Burma, including the whole6 NO. 19481959 DOWLING: PAPILLAE 7of the Indo-Chinese subregion. Reptilia and Amphibia. III. Ser-pentes. London, Taylor and Francis, Ltd., xii+583 pp., 166 figs.,1 map.STEJNEGER, LEONHARD, AND THOMAS BARBOUR1933. A check list of North American amphibians and reptiles. Third edi-tion. Cambridge, Harvard University Press, xiv+ 185 pp.

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