Trauth, Stanley E.

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Journal of the Arkansas Academy of ScienceVolume 45 Article 471991Posterior Maxillary Fangs of the Flathead Snake,Tantilla gracillis (Serpentes: Colubridae), UsingScanning Electron MicroscopyStanley E. TrauthArkansas State UniversityFollow this and additional works at: http://scholarworks.uark.edu/jaasPart of the Animal Studies CommonsThis article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able toread, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking priorpermission from the publisher or the author.This General Note is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the ArkansasAcademy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu.Recommended CitationTrauth, Stanley E. (1991) "Posterior Maxillary Fangs of the Flathead Snake, Tantilla gracillis (Serpentes: Colubridae), Using ScanningElectron Microscopy," Journal of the Arkansas Academy of Science: Vol. 45 , Article 47.Available at: http://scholarworks.uark.edu/jaas/vol45/iss1/47Proceedings Arkansas Academy of Science, Vol.45, 1991 133General NotesMETZGAR, L.H. 1979. Dispersion patterns in aPeromyscus population. J.Mamm. 60:129-145.MYTON, B. 1974. Utilization of space by Peromyscus leucopus and othersmall mammals. Ecol. 55:277-290.PRICE, P.K. and M.L.KENNEDY. 1980. Genie relationships in the white-footed mouse, Peromyscus leucopus, and the cotton mouse,Peromyscus gossypinus. Amer. Midland Nat. 103:73-82.SEALANDER, J.A. and G.A. HEIDT. 1990. Arkansas mammals. The Univ.of Arkansas Press, Fayetteville. 308 pp.SUGG, D.W., M.L.KENNEDY, and G.A. HEIDT. 1990. Morphologicalvariation in the Texas mouse, Peromyscus attwateri. J. Mamm.71:309-317.TAJTT, M.J. 1981. The effect ofextra food on small rodent populations. I.Deermice (Peromyscus maniculatus). J. Animal Ecol. 50:11-124.WOLFF, J.O., M.H. FREEBERG, and R.D. DUESER. 1983. Interspecificterritoriality in two sympatric species of Peromyscus (Rodentia:Cricetidae). Behav. Ecol. and Sociobiol. 12:237-248.WOLFF, J.O. 1985. The effects ofdensity, food, and interspecific interfer-ence on home range size in Peromyscus leucopus and Peromyscusmaniculatus. Can. J. Zool. 63:2657-2662.JOHN A.PEPPERS, DAVIDW. ROYAL, and GARY A.HEIDT,Department ofBiology, University of Arkansas at LittleRock, LittleRock, AR 72204.POSTERIOR MAXILLARYFANGS OF THE FLATHEAD SNAKE, TANTILLAGRACILIS(SERPENTES: COLUBRIDAE), USING SCANNING ELECTRON MICROSCOPYOpisthoglyphous snakes constitute a group of more or less venomous, rear-fanged species within the family Colubhdae (Smith, 1952; Fitch, 1970;Bellairs, 1970; Porter, 1972). The fangs reside on the posterior end of the maxillary bone and are larger, grooved, and often recurved compared toother maxillaryteeth. Injection of venom into prey is accomplished by chewing the victims in the so-called "slash and swab" method (McDowell, 1986); the poison is releasedfrom the parotid gland (Duvernoy's gland) through a single duct which opens into a furrow along the lateral sides of the teeth.The genus Tantilla, a New World group of small colubrid snakes comprising around 46 species, ranges throughout most of the southeastern and south-central United States (Telford, 1966) and is found in parts of the arid southwestern United States. The group is characterized by a combination of characterswhich includes the presence ofposterior maxillary grooved teeth (Wilson, 1982). Hardy and Cole (1968) and Savitzky (1983) illustrated the maxillary bone ofTantilla and showed the grooved nature ofthe fangs; i.e., the grooves lie on the lateral face of the teeth. The present study examines the fangs and other maxillaryteeth of the flathead snake, Tantilla gracilis, for the first time using scanning electron microscopy in order to reveal their surface morphology.The left maxilla of 14 adult and juvenile specimens of Tantilla gracilis collected from the Interior Highlands of Arkansas were prepared for scanningelectron microscopy (SEM). Each maxilla was removed using jewelers forceps and microscissors, stripped of muscle and connective tissue, and placed into vialsof 70% ethanol. Routine laboratory techniques were employed to prepare teeth for SEM (Dawes, 1988). Maxillae were dehydrated in a graded series of ethanoland amyl acetate, dried with a Samdri critical point dryer, coated with gold/palladium in a Hummer IVsputter coater, and viewed with a JEOL100 CXIITEM-SCAN electron microscope at an accelerating voltage of 40 kV. All snakes and prepared tissues are deposited in the Arkansas State University Museum ofZoology.Allmaxillary teeth of Tantilla gracilis showed varying degrees of structural modification (Figs. 1 and 2). The fangs are of two basic types: 1)curved and2) linear. Also, the nature ofthe groove differed between these two types. Two fangs per maxilla is the general rule (excluding replacement fangs) in this species(Fig. IB and E), although one specimen (Fig. ID)exhibited three fangs. Inmost cases, fangs were separated from the anterior maxillary teeth by a space ordiastema (Fig. 1G). The fangs of juveniles (Fig. 1A and B) are similar to those of adults (e.g., Fig. IE)in that the fangs are curved, and the grooves project ante-rio-laterally. However, the linear fang type is straighter, and grooves project laterally (Fig. 1C and D). The fang groove, a concavity running the entire labial sur-face of the fang, is situated between the mesial and distal surfaces; the groove ispresumably formed by an expansion ofdental ridges (Wright et ai, 1979; Vaethet al., 1985) that are characteristic of all maxillary teeth. The dental ridges are, however, more conspicuous in teeth near the fangs (Fig. IFand G; Fig. 2D) com-pared to anterior teeth (Fig. 2C) and contribute to the semblance of grooves most noticeable on teeth near the fangs. Anterior maxillary teeth may also exhibitdental ridges that possess serrations (Fig. 2C), whereas, in other instances, these ridges appear smooth (Fig. 2D).133Journal of the Arkansas Academy of Science, Vol. 45 [1991], Art. 47Published by Arkansas Academy of Science, 1991Arkansas Academy of ScienceFigure 1.Scanning election micrographs of maxillae and posteriormaxillary fangs ofTantUla gracilis. Snout-vent length =SVL. A.Labial view of fang ofa juve-nile (87 mm SVL);DS= distal surface. B. Labial viewof fangs of a juvenile (76 mm SVL). C. Ventral viewof fang of adult male (147 mm SVL)illustrating themesial (MS) and distal surfaces (magnification the same as A). D. Adultmale (inC)exhibiting three fangs (middle one broken off).The anteroposterior axis ofthe maxilla (A-P) showing grooves of fangs facing outward. E. Fangs ofan adult male (152 mm SVL);magnification the same as in D. F. Maxillary teeth craniadto fangs showing apparent grooves; LS= labial surface; DR=dental ridge. Magnification the same as inB. G. Maxillaofan adult female (137 mm SVL);LAF=lateral anterior foramina; M=maxillary teeth (same as inF);F= fang. H. Maxilla ofan adult male (inE). Arrows point to fangs (magnification as in G).134134Journal of the Arkansas Academy of Science, Vol. 45 [1991], Art. 47http://scholarworks.uark.edu/jaas/vol45/iss1/47Proceedings Arkansas Academy of Science, Vol.45, 1991 135General NotesFigure 2. Scanning electron micrographs of maxillary fangs and anterior maxillary teeth of Tantilla gracilis. A.Cross section ofa fang broken near its base. Theanteroposterior axis (A-P) of the maxilla reveals groove (G)facing slightly craniad and shows the mesial portion of tooth which is larger than the distal portion.B.Magnification of A.Pointer separates the outer enamel layer (EN) from the inner dentine (DE). Notice the dentine is quite porous. Arrow points laterally. C.End-on view of an anterior maxillary tooth (tip broken off) showing serrated dental ridges (DR) on both the mesial and distal surfaces. D. Anterior maxillarytooth showing dental ridge on mesial surface. Magnification as in A.Tantilla gracilis feeds primarily on arthropods (Carpenter, 1958; Collins, 1982; Johnson, 1987) and, especially, their soft-bodied larvae. As with otherinsectivorous, opisthoglyphous snakes (Savitsky, 1983; Vaeth et al., 1985), the anterior maxillary teeth ofT. gracilis primarily serve to engage and penetrate prey.Then, immobilization ofprey is accomplished by venom injection using the posterior maxillary fangs.LITERATURE CITEDBELLAIRS, A. 1970. The life of reptiles. Vol. II.The Universe NaturalHistory Series. Universe Books. New York. 590 pp.COLLINS, J.T. 1982. Amphibians and reptiles in Kansas. Univ. KansasMus. Nat. Hist. Publ. Ed. Ser. 1:1-283.CARPENTER, C.C. 1958. Reproduction, young, eggs and foods ofOklahoma snakes. Herpetologica. 14:113-115.DAWES, C.J. 1988. Introduction to biological electron microscopy: theoryand techniques. Ladd Research Industries, Inc. Burlington. 315 pp.135Journal of the Arkansas Academy of Science, Vol. 45 [1991], Art. 47Published by Arkansas Academy of Science, 1991Proceedings Arkansas Academy of Science, Vol.45, 1991136Arkansas Academy of ScienceFITCH, H.S. 1970. Reproductive cycles inlizards and snakes. Univ. KansasMus. Nat. Hist., Misc. Publ. No. 52. 247 pp.r)Y,L.M.and C.J. COLE. 1968. Morphological variation ina popula-tion of the snake, Tantilla gracilis Baird and Girard. Univ. KansasMus. Nat. Hist 17:613-629.OHNSON, T.R. 1987. The amphibians and reptiles of Missouri. MissouriDept. of Conservation. Jefferson City. 368 pp.MCDOWELL, S.B. 1986. The architecture of the corner of the mouth ofcolubroid snakes. J. Herpetol. 20:353-407.PORTER, K.R. 1972. Herpetology. W.B. Saunders Co. Philadelphia. 524pp.SAVITZKY, A.H. 1983. Coadapted character complexes among snakes:fossoriality, piscivory, and durophagy. Amer. Zool. 23:397-409.SMITH, II.M.1952. A revised arrangement ofmaxillary fangs of snakes.Turtox News. 30:214-218.TELFORD, S.R., JR. 1966. Variation among the southeastern crownedsnakes, genus Tantilla. Bull.Florida St. Mus. Biol. Sci. 10:261-304.VAETH,R.H., D.A.ROSSMAN, and W. SHOOP. 1985. Observations oftooth surface morphology in snakes. J. Herpetol. 19:20-26.WILSON, L.D. 1982. TantUla. Cat Amer. Amph. Rept. 307.1-307-4.WRIGHT, D.L., K.V.KARDONG, and D.L. BENTLEY. 1979. The func-tional anatomy of the teeth of the western terrestrial garter snake,Thamnophis elegans. Herpetologica. 35:223-228.STANLEYE. TRAUTH, Department ofBiological Sciences, Arkansas State University, State University, AR 72467.CORRECTION-In the article "Sexual dimorphism and intersexual differences inresource allocations of a dioecious shrub, Lindera melissifolia (Walt.)Blume" by Richardson, Wright, and Walker which appeared in Volume 44 (1990) of the Proceedings of the Arkansas Academy ofScience, Page 101, Column 2,Line 11, "male 623.0" should read "male 62.0".136Journal of the Arkansas Academy of Science, Vol. 45 [1991], Art. 47http://scholarworks.uark.edu/jaas/vol45/iss1/47

Posterior Maxillary Fangs of the Flathead Snake, Tantilla gracillis (Serpentes: Colubridae), Using Scanning Electron Microscopy

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Journal of the Arkansas Academy of Science Volume 45 Article 47 1991 Posterior Maxillary Fangs of the Flathead Snake, Tantilla gracillis (Serpentes: Colubridae), Using Scanning Electron Microscopy Stanley E. Trauth Arkansas State University Follow this and additional works at: https://scholarworks.uark.edu/jaas  Part of the Animal Studies Commons Recommended Citation Trauth, Stanley E. (1991) "Posterior Maxillary Fangs of the Flathead Snake, Tantilla gracillis (Serpentes: Colubridae), Using Scanning Electron Microscopy," Journal of the Arkansas Academy of Science: Vol. 45 , Article 47. Available at: https://scholarworks.uark.edu/jaas/vol45/iss1/47 This article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able to read, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This General Note is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu. Proceedings Arkansas Academy of Science, Vol.45, 1991 133General NotesMETZGAR, L.H. 1979. Dispersion patterns in aPeromyscus population. J.Mamm. 60:129-145.MYTON, B. 1974. Utilization of space by Peromyscus leucopus and othersmall mammals. Ecol. 55:277-290.PRICE, P.K. and M.L.KENNEDY. 1980. Genie relationships in the white-footed mouse, Peromyscus leucopus, and the cotton mouse,Peromyscus gossypinus. Amer. Midland Nat. 103:73-82.SEALANDER, J.A. and G.A. HEIDT. 1990. Arkansas mammals. The Univ.of Arkansas Press, Fayetteville. 308 pp.SUGG, D.W., M.L.KENNEDY, and G.A. HEIDT. 1990. Morphologicalvariation in the Texas mouse, Peromyscus attwateri. J. Mamm.71:309-317.TAJTT, M.J. 1981. The effect ofextra food on small rodent populations. I.Deermice (Peromyscus maniculatus). J. Animal Ecol. 50:11-124.WOLFF, J.O., M.H. FREEBERG, and R.D. DUESER. 1983. Interspecificterritoriality in two sympatric species of Peromyscus (Rodentia:Cricetidae). Behav. Ecol. and Sociobiol. 12:237-248.WOLFF, J.O. 1985. The effects ofdensity, food, and interspecific interfer-ence on home range size in Peromyscus leucopus and Peromyscusmaniculatus. Can. J. Zool. 63:2657-2662.JOHN A.PEPPERS, DAVIDW. ROYAL, and GARY A.HEIDT,Department ofBiology, University of Arkansas at LittleRock, LittleRock, AR 72204.POSTERIOR MAXILLARYFANGS OF THE FLATHEAD SNAKE, TANTILLAGRACILIS(SERPENTES: COLUBRIDAE), USING SCANNING ELECTRON MICROSCOPYOpisthoglyphous snakes constitute a group of more or less venomous, rear-fanged species within the family Colubhdae (Smith, 1952; Fitch, 1970;Bellairs, 1970; Porter, 1972). The fangs reside on the posterior end of the maxillary bone and are larger, grooved, and often recurved compared toother maxillaryteeth. Injection of venom into prey is accomplished by chewing the victims in the so-called "slash and swab" method (McDowell, 1986); the poison is releasedfrom the parotid gland (Duvernoy's gland) through a single duct which opens into a furrow along the lateral sides of the teeth.The genus Tantilla, a New World group of small colubrid snakes comprising around 46 species, ranges throughout most of the southeastern and south-central United States (Telford, 1966) and is found in parts of the arid southwestern United States. The group is characterized by a combination of characterswhich includes the presence ofposterior maxillary grooved teeth (Wilson, 1982). Hardy and Cole (1968) and Savitzky (1983) illustrated the maxillary bone ofTantilla and showed the grooved nature ofthe fangs; i.e., the grooves lie on the lateral face of the teeth. The present study examines the fangs and other maxillaryteeth of the flathead snake, Tantilla gracilis, for the first time using scanning electron microscopy in order to reveal their surface morphology.The left maxilla of 14 adult and juvenile specimens of Tantilla gracilis collected from the Interior Highlands of Arkansas were prepared for scanningelectron microscopy (SEM). Each maxilla was removed using jewelers forceps and microscissors, stripped of muscle and connective tissue, and placed into vialsof 70% ethanol. Routine laboratory techniques were employed to prepare teeth for SEM (Dawes, 1988). Maxillae were dehydrated in a graded series of ethanoland amyl acetate, dried with a Samdri critical point dryer, coated with gold/palladium in a Hummer IVsputter coater, and viewed with a JEOL100 CXIITEM-SCAN electron microscope at an accelerating voltage of 40 kV. All snakes and prepared tissues are deposited in the Arkansas State University Museum ofZoology.Allmaxillary teeth of Tantilla gracilis showed varying degrees of structural modification (Figs. 1 and 2). The fangs are of two basic types: 1)curved and2) linear. Also, the nature ofthe groove differed between these two types. Two fangs per maxilla is the general rule (excluding replacement fangs) in this species(Fig. IB and E), although one specimen (Fig. ID)exhibited three fangs. Inmost cases, fangs were separated from the anterior maxillary teeth by a space ordiastema (Fig. 1G). The fangs of juveniles (Fig. 1A and B) are similar to those of adults (e.g., Fig. IE)in that the fangs are curved, and the grooves project ante-rio-laterally. However, the linear fang type is straighter, and grooves project laterally (Fig. 1C and D). The fang groove, a concavity running the entire labial sur-face of the fang, is situated between the mesial and distal surfaces; the groove ispresumably formed by an expansion ofdental ridges (Wright et ai, 1979; Vaethet al., 1985) that are characteristic of all maxillary teeth. The dental ridges are, however, more conspicuous in teeth near the fangs (Fig. IFand G; Fig. 2D) com-pared to anterior teeth (Fig. 2C) and contribute to the semblance of grooves most noticeable on teeth near the fangs. Anterior maxillary teeth may also exhibitdental ridges that possess serrations (Fig. 2C), whereas, in other instances, these ridges appear smooth (Fig. 2D).133Journal of the Arkansas Academy of Science, Vol. 45 [1991], Art. 47Published by Arkansas Academy of Science, 1991Arkansas Academy of ScienceFigure 1.Scanning election micrographs of maxillae and posteriormaxillary fangs ofTantUla gracilis. Snout-vent length =SVL. A.Labial view of fang ofa juve-nile (87 mm SVL);DS= distal surface. B. Labial viewof fangs of a juvenile (76 mm SVL). C. Ventral viewof fang of adult male (147 mm SVL)illustrating themesial (MS) and distal surfaces (magnification the same as A). D. Adultmale (inC)exhibiting three fangs (middle one broken off).The anteroposterior axis ofthe maxilla (A-P) showing grooves of fangs facing outward. E. Fangs ofan adult male (152 mm SVL);magnification the same as in D. F. Maxillary teeth craniadto fangs showing apparent grooves; LS= labial surface; DR=dental ridge. Magnification the same as inB. G. Maxillaofan adult female (137 mm SVL);LAF=lateral anterior foramina; M=maxillary teeth (same as inF);F= fang. H. Maxilla ofan adult male (inE). Arrows point to fangs (magnification as in G).134134Journal of the Arkansas Academy of Science, Vol. 45 [1991], Art. 47https://scholarworks.uark.edu/jaas/vol45/iss1/47Proceedings Arkansas Academy of Science, Vol.45, 1991 135General NotesFigure 2. Scanning electron micrographs of maxillary fangs and anterior maxillary teeth of Tantilla gracilis. A.Cross section ofa fang broken near its base. Theanteroposterior axis (A-P) of the maxilla reveals groove (G)facing slightly craniad and shows the mesial portion of tooth which is larger than the distal portion.B.Magnification of A.Pointer separates the outer enamel layer (EN) from the inner dentine (DE). Notice the dentine is quite porous. Arrow points laterally. C.End-on view of an anterior maxillary tooth (tip broken off) showing serrated dental ridges (DR) on both the mesial and distal surfaces. D. Anterior maxillarytooth showing dental ridge on mesial surface. Magnification as in A.Tantilla gracilis feeds primarily on arthropods (Carpenter, 1958; Collins, 1982; Johnson, 1987) and, especially, their soft-bodied larvae. As with otherinsectivorous, opisthoglyphous snakes (Savitsky, 1983; Vaeth et al., 1985), the anterior maxillary teeth ofT. gracilis primarily serve to engage and penetrate prey.Then, immobilization ofprey is accomplished by venom injection using the posterior maxillary fangs.LITERATURE CITEDBELLAIRS, A. 1970. The life of reptiles. Vol. II.The Universe NaturalHistory Series. Universe Books. New York. 590 pp.COLLINS, J.T. 1982. Amphibians and reptiles in Kansas. Univ. KansasMus. Nat. Hist. Publ. Ed. Ser. 1:1-283.CARPENTER, C.C. 1958. Reproduction, young, eggs and foods ofOklahoma snakes. Herpetologica. 14:113-115.DAWES, C.J. 1988. Introduction to biological electron microscopy: theoryand techniques. Ladd Research Industries, Inc. Burlington. 315 pp.135Journal of the Arkansas Academy of Science, Vol. 45 [1991], Art. 47Published by Arkansas Academy of Science, 1991Proceedings Arkansas Academy of Science, Vol.45, 1991136Arkansas Academy of ScienceFITCH, H.S. 1970. Reproductive cycles inlizards and snakes. Univ. KansasMus. Nat. Hist., Misc. Publ. No. 52. 247 pp.r)Y,L.M.and C.J. COLE. 1968. Morphological variation ina popula-tion of the snake, Tantilla gracilis Baird and Girard. Univ. KansasMus. Nat. Hist 17:613-629.OHNSON, T.R. 1987. The amphibians and reptiles of Missouri. MissouriDept. of Conservation. Jefferson City. 368 pp.MCDOWELL, S.B. 1986. The architecture of the corner of the mouth ofcolubroid snakes. J. Herpetol. 20:353-407.PORTER, K.R. 1972. Herpetology. W.B. Saunders Co. Philadelphia. 524pp.SAVITZKY, A.H. 1983. Coadapted character complexes among snakes:fossoriality, piscivory, and durophagy. Amer. Zool. 23:397-409.SMITH, II.M.1952. A revised arrangement ofmaxillary fangs of snakes.Turtox News. 30:214-218.TELFORD, S.R., JR. 1966. Variation among the southeastern crownedsnakes, genus Tantilla. Bull.Florida St. Mus. Biol. Sci. 10:261-304.VAETH,R.H., D.A.ROSSMAN, and W. SHOOP. 1985. Observations oftooth surface morphology in snakes. J. Herpetol. 19:20-26.WILSON, L.D. 1982. TantUla. Cat Amer. Amph. Rept. 307.1-307-4.WRIGHT, D.L., K.V.KARDONG, and D.L. BENTLEY. 1979. The func-tional anatomy of the teeth of the western terrestrial garter snake,Thamnophis elegans. Herpetologica. 35:223-228.STANLEYE. TRAUTH, Department ofBiological Sciences, Arkansas State University, State University, AR 72467.CORRECTION-In the article "Sexual dimorphism and intersexual differences inresource allocations of a dioecious shrub, Lindera melissifolia (Walt.)Blume" by Richardson, Wright, and Walker which appeared in Volume 44 (1990) of the Proceedings of the Arkansas Academy ofScience, Page 101, Column 2,Line 11, "male 623.0" should read "male 62.0".136Journal of the Arkansas Academy of Science, Vol. 45 [1991], Art. 47https://scholarworks.uark.edu/jaas/vol45/iss1/47

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Posterior Maxillary Fangs of the Flathead Snake, Tantilla gracillis (Serpentes: Colubridae), Using Scanning Electron Microscopy

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