”W -\..::.< o ’F’n. . “.1" I4 ‘ “1.9 I 14. W 4-3 ., \ 5.. m. . F‘k‘ r «mg-.3" , s. ‘ ‘ iiim‘g 97“; "0,";"1‘." '. afififx 3k" ‘ ’4 I _ ‘ '3' '. A ‘ ~ ’ 1‘;l':‘. v, .s. . , '“r n. U .n; "f? .‘ - “Jr ‘1;'as£. 3‘ It“ ”-.'“L'J‘1 :J‘E"? IUl‘o ‘ - ' H is: ‘ N * If; :‘:::“‘ Ltfi‘ \\' 'l o“... l . .7. v. 26.1,; .9.~ n. . -\ - ‘<‘ . . | I ”NMLHHJ. .. 'v'm I; {, :' ‘ , ,,‘ “"HH‘I.1:\)'HH‘ J'VH'.0"“" ‘5. 'HMI'. _ .-., w- Hzrrn-yvrw . Hl'fih 1 ‘ :\| u} L . .'.' [M ', ' ”I_1..|.'L' '“v-fl‘mku’h‘l‘ This is to certify that the thesis entitled TOOTH REPLACEMENT gN MYOTIS ALBESCENS (E. GEOFFROY ST. HILLAIRE) presented by W1 1 liam David Webs ter has been accepted towards fulfillment of the requirements for Mejia—degree in Science Zoo 1 ogy I @meig e EH v Major professor Date 5 May 1978 0-7639 TOOTH REPLACEMENT IN MYOTIS ALBESCENS I (E. GEOFFROY ST. HILLAIRE) By William David Webster A THESIS Submitted to Midhigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Zoology 1978 ABSTRACT TOOTH REPLACEMENT IN MYOTIS ALBESCENS (E. GEOFFROY ST. HILLAIRE) By William David Webster Tooth replacement patterns in the neotropical Myotis albescens are similar to the temperate M, lucifugus. There is some indication that the length of foraging may affect tooth replacement, but both Myotis species appear similar in their feeding strategies. Selective pressures have favored an earlier eruption, more postero-lingual curvature, more cuspidation, and more crown exposure in the anterior milk teeth. The adaptive significance of the more elaborate anterior milk teeth is to allow the suckling to better grasp the nipple. The lacteal premolars, which probably do not assist in nursing, are simple Spicules. Sequences of deciduous-tooth shedding and permanent-tooth eruption are intimately related to the change to an insectivorous diet. As the weanling becomes volant, insects become the major food item. Correlatively, more deciduous teeth are lost and more permanent teeth penetrate the oral epithelium. ACKNOWLEDGEMENTS I am deeply indebted to Dr. Rollin H. Baker, Chairman of my Advisory Committee, for his invaluable assistance and guidance during this investigation. I am also grateful to Dr. J. Alan Holman and Dr. Harold H. Prince for their contributions as members of my Advisory Committee. Additional gratitude is extended to those at the University of North Carolina at Wilmington, especially Dr. Charles M. Fugler, for their guidance throughout this study. I would like to extend a special thanks to Mr. and Mrs. Donald Wébster and Kerry M. webster for their constant support and encouragement throughout this study. 11 TABLE OF CONTENTS LIST OF TABLES . . . . . . . . . . . . . . LIST OF FIGURES . . . . . . . . . . . . . . INTRODUCTION . . . . . . . . . .v. . . . . MATERIALS AND METHODS . . . . . . . . . . . RESULTS Morphology of the Deciduous Teeth . . Eruption of the Deciduous Teeth . . . Eruption of the Permanent Teeth . . . Shedding of the Deciduous Teeth . . . Analysis of Stomach Contents . . . . . DISCUSSION . . . . . . . . . . . . . . . . SUMMARY . . . . . . . . . . . . . . . . . . APPENDIX A: TAXONOMY, BIOGEOGRAPHY, AND ECOLOGY OF MYOTIS ALBESCENS . . . . . APPENDIX B: REVIEW OF THE LITERATURE . . . APPENDIX C: LOCATION OF MENDEZ, ECUADOR . APPENDIX D: PROCEDURE FOR PREPARING SKULLS USING ALIZARIN RED S AND KOH . APPENDIX E: PHOTOGRAPHS OF DECIDUOUS TEETH AND JAW MORPHOLOGY IN MYOTIS ALBESCENS LITERATURE CITED . . . . . . . . . . . . . iii Page iv 13 16 19 21 31 33 35 40 41 42 SO LIST OF TABLES Table Page 1. Relative growth classes of Mygtis albescens based on phalangeal ossification and forearm length . . . . 4 2. Numbers of erupted deciduous teeth in fetal Myotis albescens . . . . . . . . . . . . . . 9 3. Numbers of erupted permanent teeth in neonate Myotis albescens . . . . . . . . . . . . . 14 4. Numbers of remaining deciduous teeth in neonate Myotis albescens . . . . . . . . . . . . . 17 5. Prior studies on tooth replacement in the miroptera C O O O O O O O O O O O 0 O C O O O 36 iv Table 1. LIST OF FIGURES Page Morphology of the deciduous teeth in_Myotis albescens . . . . . . . . . . . . . . . . . 7 The known range of Myotis albescens . . . . ... . . . 34 Location of Méndez, Ecuador . . . . . . . . . . . . . 40 Photographs of upper deciduous teeth . . . . . . . . 43 Photographs of lower deciduous teeth . . . . . . . . 45 Photographs of jaw morphology . . . . . . . . . . . . 47 A. Lower jaw, complete deciduous dentition (UNC-W E301F) Upper jaw, complete deciduous dentition (UNC-W E301F) Lower jaw, partial eruption of permanent teeth and shedding of deciduous teeth (UNC-W E225) Upper jaw, partial eruption of permanent teeth and shedding of deciduous teeth (UNC-W E225) Photographs of jaw morphology . . . . . . . . . . . . 49 E. Lower jaw, partial eruption of permanent teeth and shedding of deciduous teeth (MSU 23969) Upper jaw, partial eruption of permanent teeth and shedding of deciduous teeth (MSU 23969) Lower jaw, complete permanent dentition (UNC-W E266) Upper jaw, complete permanent dentition (UNC-W E266) INTRODUCTION Tooth replacement, in which a set of deciduous teeth is replaced by permanent teeth, occurs exclusively in diphyodont mammals. Replacement may extend over many years, as in several ruminants, or last but a few days, as in some pinnipeds (Flower, 1871). The process of tooth replacement encompasses deciduous- tooth eruption, permanent-tooth eruption, and deciduous-tooth shedding. The sequences of eruption and shedding are also integral processes of replacement, as are deciduous-tooth and permanent- tooth morphology. Mammalogists have classically utilized dentition diversity as a means of species identification. Because similar mammals exhibit similar dental characteristics, phylogenetic relationships were established, in part, by dental characteristics. Leche (1875, 1877, 1878) proposed that generic and familial relationships could be inferred from comparisons of tooth replacement. In the case of bats, Phillips (1971) formulated phylogenetic relationships within glossophagine genera on the sequences of tooth replacement and dental morphology. The Paraguay myotis, Myotis albescens, has received detailed systematic and biogeographic analyses (Vieira, 1942; Sanborn, 1949; Lara, 1950; Cabrera, 1958; Hall and Kelson, 1959; Aellen, 1970; LaVal, 1973; Baker, 1974)(Appendix A). However, tooth replacement has received scant attention. LaVal (1973), in his review of the neotropical species of Myotis, ignored tooth replacement. In view of the paucity of documented evidence on tooth replacement and its possible systematic significance, the purpose of this study is to determine and describe the replacement patterns in Myotis albescens. All aspects of tooth replacement are described for the temperate Myotis lucifuggg except the sequence of eruption in the deciduous teeth (Stegeman, 1956; Fenton, 1970). Myotis albescens will be compared with M, lucifugus to determine similarities and differences in tooth replacement. MATERIALS AND METHODS On 11 and 12 June 1975, 191 individuals from a population of Myotis albescens were collected. The bats were captured by hand during daylight hours from the attic of the school in Mendez, Provincia de Morona Santiago, Ecuador (2.43° S, 78.19° W, 914 m.) (Appendix C). The specimens were etherized and preserved in 10 percent formalin solution. Upon returning to the laboratory, the specimens were transferred to 30 percent ethanol. Currently the bats are deposited in the Vertebrate Collections, University of North Carolina at Wilmington (UNC—W E195-E360), and The Museum, Michigan State University (MSU 23955-23979). All females were internally examined for pregnancy. Because the eruption of deciduous teeth precedes parturition, all fetuses were removed to determine the eruption sequence of milk teeth. Further investigation revealed that milk-tooth eruption did not commence until the fetal crown-rump length exceeded ten millimeters. Consequently, fetuses larger than ten millimeters in crown-rump length were examined for the eruption of lacteal teeth. Twenty-six fetuses, hereafter designated by the addition of 'F' after the maternal catalogue number, were retained and preserved in 30 percent ethanol. The left forearm and the first phalanx of the left fifth digit were measured with Vernier calipers in neonate, juvenile, and adult individuals. When the epiphyses and diaphyses of the phalanges were not entirely ossified, the percentage of phalangeal ossification was determined as follows: phalangeal maximum length of ossifiedjphalanx (mm) % ossification ( )° maximum length between epiphyses (mm) X 100 = The population sample from Mendez was arbitrarily allocated to four growth classes: fetus, neonate, juvenile, and adult. The growth classes were determined by phalangeal ossification and forearm length (Table 1). Table 1. Relative growth classes of Myotis albescens based on phalangeal ossification and forearm length. GROWTH PHALANGEAL FOREARM NUMBER CLASS OSSIFICATION (Z) LENGTH (MM) EXAMINED Fetus 0-49 0-11 26 Neonate 50-89 11-32 13 Juvenile 90-99 33-38 102 Adult 99 34-39 76 In that sexual dimorphism has not been noted in dental characteristics in vespertilionids, the sexes were combined. Adult skulls were cleaned by dermestids (Qermestes lardariug). Fetal, neonate, and juvenile skulls were cleared with KOH and stained with Alizarin Red S (gigg_Appendix D for procedure). The retention of teeth in the alveoli was therefore ensured. All skulls were examined for deciduous-tooth eruption, permanent-tooth eruption, and deciduous-tooth shedding with the aid of monocular and binocular microscOpes. The deciduous-tooth morphology is described and illustrated. It is assumed that the deciduous dentition, once erupted, exhibit no ontogentic change, except for the progressive lengthening of the root resulting in firmer alveolar attachment. Therefore, fetal teeth were used to describe the morphology of lacteal teeth. Fetal milk-teeth were procured by gently removing the tooth from the alveolus. Gum tissue adhering to the tooth was removed with Hydrochloric Acid (50 percent aqueous). The tooth was then stained with Alizarin Red S (5 percent aqueous), and wet mounted with balsalm. Photographs were taken from the prepared slides. Neonate digestive tracts were examined for maternal milk, insects, or both. Hence, initiation to an insectivorous diet was related to deciduous-tooth shedding and permanent-tooth eruption. Tooth nomenclature follows Miller (1907). Upper case and lower case letters indicate permanent and deciduous teeth, respectively. Position of the number subsequent to the letter signify the position of the tooth, subscripts indicate lower jaw and superscripts indicate upper jaw. RESULTS The observations are, for clarity, grouped into the distinct phases of tooth replacement: deciduous-tooth morphology, deciduous- tooth eruption, permanent-tooth eruption, and deciduous-tooth shedding. The stomach contents of several younger specimens are analized and incorporated where appropriate. Morphology of the Deciduous Teeth The morphology of the deciduous teeth was ascertained from two fetuses with complete deciduous eruption (UNC-W E334F, MSU 23961F). No root absorption had begun, yet some root damage was inevitable due to the Hydrochloric Acid. Cingula were not evident. The deciduous incisors exhibited an increasing tendency to have a central postero—lingually directed cusp bordered laterally by smaller but parallel cusps (Figure 1, Appendix E), exempli‘gratia, the first milk incisors (lower only) were slightly trilobed. The remaining upper and lower incisors were more cuspidate. The median cusp was markedly larger than the lateral lobes, especially in the upper deciduous incisors. The second and third incisors also were more lingually directed, the first incisors being more posteriorly directed. The lacteal canines were unequally bilobed and projected posters-lingually (Figure 1, Appendix E). The upper canines had a il é? 0.74 mm i2 8 0.95 mm 12 f 0.81 mm 13 f 1.02 mm 13 f 0.70 mm cl i 1.30 mm cl KLOS m p3 6?. 0.98 mm p 1.02 mm 3 p4 0.77 mm p4 6? 0.98 mm Figure l. Morphology of the deciduous teeth in Myotis albescens. superior cusp that is not strongly recurved. In contrast, the superior cusp of the lower canines was sharply angled posteriorly. All inferior talons arose near the gingiva and were directed caudally. Deciduous premolars were trilobed, but the lateral lobes were much reduced and appeared as laterally expanded crowns (Figure 1, Appendix E). The milk premolars, essentially straight, were somewhat recurved. The first lower incisors and all premolars were slightly extended from the gingiva. The lacteal canines had erupted more than the other deciduous teeth, and the second and third incisors were intermediately extended (Figure 1). Additionally, the milk canines were longer from root to crown than either incisors or premolars. Eruption of the Deciduous Teeth The eruption of the lacteal teeth was determined from 26 fetal Myotis albescens (Table 2). Teeth were considered erupted when the tooth first penetrated the gingiva and entered the oral cavity. No teeth had erupted in three specimens (E325F, 23970F, E214F). The first teeth to erupt were the lower third incisors (E208F). The upper canines were the next teeth to penetrate the gingiva (E300F), and were followed by the upper third incisors, lower canines, and lower second incisors (E257F, E225F). The upper second and lower first incisors erupted (E225F). The lower third ~— ~.m 02 m . m u . m ”Home 3-qu 3w 0;: m . m u . m ENS 3.23 To ES mmm. . m u . m mime 3-02: Cw 0.3 m . m u . m mmmmm 3:02: we HS m . m o . m ESE 2.35 A: ~.2 m . WI” 0 . m .502 3-85 is QS m . m u . m .183 3.25 m6 m1: mmm. . m u . mulm $13 3:28 fin .2: m . mmm. o . m 832 a: fin 9: m . m o . m .53 3-075 Euza Elmore mauzmo Smizzomo 92.5mm Emma mmmzez zmfiwmmm .mcoomopam canoe: Houom a“ nuoou ceasefioov vuuoouo mo phonesz .N manna 10 m.OH 5.5 m.m «.5 m.5 0.x 5.5 0.0H m.m 5.5 m.w m.5H 0.0H 5.mH m.mH m.¢H o.qa «.ma n.5H 0.0H n.0H m.mH "u" H T H H A H I r-l T H H A 'F‘ H H H '7‘ H ‘T‘ r-i H I r-i '7‘ H 7 F4 '1" F4 F! I H T H T' H H H 'T' H 'T' H ..' IH T H mammmm pm: mflnmm SIUZD mmmmm BIUZD mHomm SIUZD mommm 3:02: hmmNm 3IUZD mmmNm 3IUZD mm5mm~ am: m5mNm 3IUZD mmfimm BIUZD h5~mm SIOZD A.s.uaouc N .Hama 11 3.3 3:. m a . m o . m a 33% 3-25 CS 3: m a . m. u . m a 323 3-25 93 2: m a . m u . m a 382 3-25 TB 3: www- a . m o . m a 338 3-25 3.5 5.: MIM- a . m o . mm. a 3.33 3-95 A.a.uaouV N magma 12 and fourth premolars followed (E328F, E303F, E227F, E318F, E297F). The last teeth to erupt were the upper third and fourth premolars (E289F, E299F, E230F, E301F, E353F, E351F, 23961F, E344F, E314F, E309F, E272F, E298F). Several specimens deviated from the sequence described. The lower fourth premolars erupted extremely early in two specimens (E208F, E257F). The upper third and fourth premolars also appeared out of sequence occasionally (E257F, E274F). One fetus (E289F) had all deciduous teeth except the lower third premolars. The lacteal teeth, with one exception, progressed steadily through the gingiva until each tooth crown was clearly evident above the gum. The exception, the lower first incisors, was in position to erupt very early in the sequence of milk-tooth eruption. However, penetration of the gingiva was not apparent until the remaining incisors had erupted. Although gingival penetration had occurred, the crown had not extended appreciably into the oral cavity. No occlusal surface was apparent in any individual. The deciduous dental formula for M, albescens is —_-i;,p%:%822. All milk teeth are ostensibly precursors to permanent teeth. The second permanent premolars and the permanent molars have no predecessors. 13 Eruption of the Permanent Teeth The eruption of the permanent teeth in 13 neonate M, albescens is depicted in Table 3. Teeth were considered erupted when the tooth crown first pierced the gingiva and entered the buccal cavity. Furthermore, Alizarin Red S stained any portion of the tooth not protected by gum tissue. Therefore, red-stained crowns accentuated erupted teeth. No permanent teeth were erupted in younger specimens (E237, E239, E244, E243). The lower first incisors were the initial teeth to penetrate the gingiva and become stained (E254). Next, the lower second incisors and lower fourth premolars pierced the gums (E242), and were followed by the lower third incisors and upper fourth premolars (E245). In the latter Specimen four pairs of teeth were visible immediately beneath the gingiva but had not penetrated the oral epithelium. The lower and upper first molars, and the lower and upper canines were erupted in the next individual (E337), and must have erupted in close succession to the previously erupted upper fourth premolars. Furthermore, the lower second premolars, upper second incisors, and lower and upper second molars had erupted in the same specimen (E337). Permanent-tooth eruption continued with the eruption of the upper second premolars and lower third molars (E201). The upper third incisors penetrated the gum (MSU 23969)-then the lower and l4 booms“ and ease uoomofi vow xafie uommofi mam xHfiE uommofi vow xHfiE powwow 050m .xawa 5Humoe uoomafi vac Jaws 3Heo ease 3Hao ease 5Hoo xafia m.om ~.5N w.om o.mH 5.mH o.NH m.HH H.HH m.m a Clo m a O|o OIO Clo ‘? m 1‘ H M I m 1‘ r-l Homm 5mmm mqmm Ncmm qmwm mqmm «qmm mmmm 5m~m BIUZD BIUZD BIUZD BIUZD 3IUZD 3IUzD BIDZD BIDZD BIUZD szmHzoo mumzosm whozmg_zm4,(P4,M1,M2,P2,cl,M1,M2),P2, M3 , I2 , I3 , (M3 , P3 , P3 . Parentheses indicate teeth that erupt simultaneously and, consequently, no definite sequence was determined. The sequence of eruption of permanent teeth in M, albescens isI1,Iz,P4,I3,P4,(M1,M1,C1,C1,P2,M2,Iz, M2 ), P2 , M3 , I3 , P3 , P3 , M3 . The sequence in M, humeralis does not adhere to those of M. lucifugus and M. albescens. The latter species exhibit partial agreement in the eruptional sequence. The sequence of eruption is similar with early-erupting teeth (11 , I2 , I3 , P4 , P4 , C1 ) and late-erupting teeth (P2 , 12 , M3 , I3 , P3 , P3 , M3 ) in M. albescens and M. lucifugus. The eruptional sequence of the intermediate teeth (M1 ,M1 , C1 , P2 , M2 , M2 ) is probably ascertainable. However, more neonate specimens must be examined to define accurately the sequence. The early eruption of the lower incisors may be associated with nursing and mastication. The lower deciduous incisors are shed immediately before the eruption of the lower permanent incisors in M. albescens and M. lucifugus. Therefore, the erupted permanent incisors may initially function as the shed milk incisors (to graSp the nipple). At this ontogenetic stage the diet becomes insectivorous. The early eruption of the incisors would facilitate the mastication of the exoskeleton of the insects. The upper canines and fourth 27 premolars erupt relatively early in M. albescens and M. lucifugus. Since the neonate consumes more insects, these teeth would presumably aid in mastication. The first and second molars, lower canines, and lower second premolars are the next group of teeth to erupt. They are mastigatory in nature. During the eruption of these teeth insects were determined to be the primary content of the stomach. Few, if any, of these teeth function in suckling although weaning is not terminated. The last teeth to erupt in M. albescens and M. lucifugus are the upper incisors, third premolars, third molars, and upper second premolars. The post-canine teeth are mastigatory. The incisors may briefly assist in nursing. However, weaning is completed soon after the full compliment of permanent teeth is attained. It is adaptively significant that teeth utilized in nursing (lower incisors) and mastication (fourth premolars) erupt as the pup initially consumes insects. The subsequent eruption of the canines and anterior molars corresponds with the eventual change to an insectivorous diet. The shedding sequence of the deciduous teeth is directly related to the eruptional sequence of the permanent teeth. The resorption of the deciduous root is triggered by the erupting permanent tooth (Aisenberg, 1966). Additionally, the permanent alveolus expands to incorporate the deciduous alveolus. The deciduous root is therefore freed from the alveolus and resorbed until it is displaced from the oral epithelium. 28 The shedding sequence of deciduous teeth 13.5: albescens 2 is 11 9 P4 9 i2 9 13 9 P4 9 i 9 c1 9 P3 9 C1 9 P3 9 13 9 The shedding sequence of M. lucifugus is 11 , p4 , iz , i3 , p4 , c1 , p3 , c1 , p3 , 12 , i3 (Stegeman, 1956; Fenton, 1970). Although divergence exists in the eruptional sequence of the canines and third premolars, the two species have a similar sequence of eruption. The relationship between permanent-tooth eruption and deciduous-tooth shedding can be better illustrated by combining both sequences. For M, albescens the combined sequences are 11 , Il,p4,12,12,P4,13,13,P4,Ml,(M1,cl,cl,1>2, M2 9 12 9 M? )9 P4 9 12 9 P2 9 C1 9 M3 9 P3 9 C1 9 P3 9 I3 9 13 9 P3 , P3 , M3 . Parenthesis indicates teeth that appear to erupt simultaneously. Fenton (1970) detailed the combined sequences for .M5 lucifugus as 11 , Il , p4 , 12 , 12 , i3 , I3 , p4 , c1 , C1 , P4 9 P3 9 C1 9 P3 9 (P4 9 M1 9 M2 9 P2 9 C1 9 M1 9 M2 )9 P2 9 M3 9 12 , 12 , i3 , I3 , (M3 , P3 ), P3 . The combined sequences are remarkably similar when allowing for variation within parentheses. Fenton (1970) found that the deciduous antecessor is always shed before the permanent superseder erupted in M, lucifugus. In M. albescens this is not true. The deciduous predecessor is shed before permanent eruption in all but four paris of teeth (p4 , c1 , c1 , 13 ) . In those teeth the permanent tooth erupts either posteriorly (p4 , i3 ) or medially (c1 , c1 ) to the deciduous tooth. Both deciduous and permanent teeth are evident (Appendix E, Figure 6, 29 C and D). It is conceivable that the weanling requires an increased crown exposure to masticate in addition to the deciduous spicules to suckle. The morphology of the deciduous teeth in M. albescens is similar of M, lucifugus. The milk premolars in both are unicuSpid. They are not as complex as those of other vespertilionids. In M} myotis (Spillman, 1927), Pizonyx vivesi (Reeder, 1953), Pipistrellus kuhli and g, gangs (Dorst, 1949), Myctalus leisleri (Matthews, 1950), and Vespertilio superans (Yoshiyuki, 1968), the milk premolars, not distinctly tricuspid, possess two accessory cusps. All vespertilionids exhibit slight postero-lingual curvature of the deciduous premolars. The morphology of the deciduous incisors and canines appears consistent in all vespertilionids. Tooth replacement and morphology may be of systematic significance. Phillips (1971) formulated phylogenetic relationships within glossophagine genera on the basis of tooth replacement and morphology. No other group of bats has been examined to determine systematic implications. Mygtis albescens and M, lucifugus have similar sequences of eruption and shedding. The deciduous tooth morphology is similar. Because of similarities in tooth replacement and morphology, latitude is apparently of no significance in the slight divergences noted in M. albescens and M. lucifugus. Diet and the correSponding feeding strategy associated with diet may be the ultimate factor affecting tooth replacement and milk-tooth morphology. In that 30 M5 albescens and M, lucifugus are both insectivorous, diet would exert similar selective pressures. As stated previously, selective pressures affecting dental characteristics probably began as the Chiroptera became volant. Chiropteran feeding strategies then radiated tremendously. Deciduous dental modifications were adapted to a particular feeding strategy. The systematic implications associated with tooth replacement are, therefore, partially dependent on the feeding strategies. SUMMARY Tooth replacement is examined in 217 fetal, neonate, juvenile, and adult Myotis albescens. Tooth replacement includes deciduous-tooth morphology, deciduous-tooth eruption, permanent-tooth eruption, and deciduous-tooth shedding. The deciduous-tooth morphology of the neotropical M, albescens is similar to the temperate M, lucifugus. The milk incisors are tri- cuspid and recurved posteriorly. The lacteal canines are bicuspid and directed postero-lingually. The deciduous premolars are unicuSpid and, although somewhat lingually directed, relatively straight. The eruptional sequence of the deciduous teeth has not been ascertained for any chiropteran. In M, albescens the incisors and canines erupt before the premolars. The sequences of permanent-tooth eruption and deciduous-tooth shedding are similar in M} albescens and 1M} lucifugus. There is a tendency for the anterior milk teeth to be replaced prior to the post-canine dentition. Because the milk teeth assist the thumbs and pedes to graSp the volant mother, tooth replacement is adaptively significant. The milk teeth which function to graSp the nipple (incisors and canines) erupt earlier than premolars. The deciduous incisors and canines are more cuspidate and recurved than premolars. Also, the milk incisors and canines extend farther into the buccal cavity than premolars. The selective pressures favoring an increased incisor and canine complexity originated as bats became volant. Diversities in feeding 31 32 strategies have differentially influenced tooth replacement. The extended foraging times of vespertilionids favored more complex anterior milk teeth (ostensibly to allow the neonate to accompany the foraging female). The short foraging times of mega- dermatids and rhinolophs favored a resorption of the milk teeth since the pups do not accompany the foraging female. Therefore, tooth replacement may be of systematic importance because of divergent feeding strategies. The similarities in tooth replacement imply systematic affinities between M. albescens and M. lucifugus. Both are insectivorous and may have extended foraging flights. The milk premolars, nonfunctional in nursing, are vestigial and appear as simple spicules. The deciduous incisors and canines are more complex. The eruptional sequences are related intimately to teeth most utilized in nursing. Anterior milk teeth are shed early. However, the early eruption of the anterior permanent teeth function as the shed milk teeth (to suckle). The eruption sequence of permanent premolars and molars corresponds to the dietary change from milk to insects. APPENDIX A APPENDIX A TAXONOMY, BIOGEOGRAPHY, AND ECOLOGY OF MYOTIS ALBESCENS Myotis albescens (B. Geoffroy St. Hillaire) 1806. Vespertilio albescens B. Geoffroy Saint-Hillaire, Ann. Mus. d'Hist. Nat. Paris 8: 204-205. (based on Azara's Chauvesouris douziéme, 1801, pp. 294-295 ig_Essais sur l'histoire naturrelle des quadrupedes de la province du Paraguay, Paris, vol. 2.) "Paraguay" 1826. Vespertilio leucggaster Wied-Neuwied, Beitrage zur Naturgeschichte von Brazilien, Weimar 2: 271-274. Moucouri River, Brazil. 1840. Vespertilio arsinoe Temminck, Monographies de Mammalogie 2: 247-248. Surinam. 1900. Myotis albescens, Thomas, Ann. Mus. Civ. Storia Nat. Genova 40: 546. 1947. Myotis argentatus Dalquest and Hall, Univ. Kan. Publs., Mus. Nat. Hist. 1: 239-242. 14 km SW Coatzocoalcos, Veracruz, Mexico. The neotropicalnyotis albescens is widely distributed, ranging from the Mexican State of Veracruz through Peru, Bolivia, and northern Argentina (Miller and Kellogg, 1955)(Figure 2). The species has not been reported from Chile or the caatinga scrub forest of eastern Brazil (LaVal, 1973). Lowland forests are the preferred habitats, however, the species is also known from montane cloud forests (LaVal, 1973). Myotis albescens is gregarious and frequently edificarian. Specimens used in this study were obtained from a nursing colony of under 1000 individuals (estimated). Of 191 specimens collected, 33 34 178 are female, juvenile, or neonate. The females have two mammae and are uniparous. Figure 2. The known range of Myotis albescens. APPENDIX B APPENDIX B REVIEW OF THE LITERATURE Permanent dental formulae of the New World Chiroptera are well documented (Miller, 1907; Hall and Kelson, 1959). However, the sequences of deciduous-tooth eruption, permanent-tooth eruption, and deciduous-tooth shedding have been determined for few species. To my knowledge the eruptional sequence of deciduous teeth is little understood for any chiropteran. The number of deciduous teeth present when the fetus was sacrificed has been described in many bats (Table 5). However, no series of fetal specimens have been examined to determine the eruptional sequence of lacteal teeth. Permanent-tooth eruption has been detailed for numerous chirop- terans (Table 5). Leche (1878) examined many species of the megachi- ropteran family Pteropodidae. It should be noted that individual specimens rather than series were usually examined. Therefore, perma- nent-tooth sequences were subjectively determined. Phillips (1971) explicated sequences of permanent-tooth eruption from series of several glossophagine species. Many authors (Miller, 1896; Matthews, 1950; Dorst, 19572; Friant, 1963; Jones, 1967; Fenton, 1970; Birney and Timm, 1975) have determined the sequences of permanent-tooth eruption in individual species. 35 36 mnwa .oaoma oausucwu oufiuuoa< H H mmwa .onowq maumHHaonmu a moonfiuum « « nnwfl .mnma .onuog aoaafia mufiooum « a wmma .onooA ovsmow>wun mHHHouoo « ... « 9. :3 3.32323 saucepan maumuuNcouaq « « a « anma .maaaaanm maHo>Ho mfiuouommmmmoa a « a « Huma .mawaafism « x « amma .uoxom pom maamum mamofixoa mfiuouomaoumozo « a e x Han .maqaaasm « * wnwa .mnwa .onoma moHoHuom owmmmommoau i. in * mummfl .3qu 33385 «3289 s « coma .comaoz Hammonuoums mauouomz * « ooma .comaoz mfimsmuommwm monocououm mmowumEoumoHHhsm « a mmwa .mmma .ozuma moumofimommwn manooaocfiam i. « 33 .5538 3mm: magnificence umefiaaofloaaam Amouom ca comma xHHE mo xoma pouocv mmmH .umuon mooum mfi>mg omvfiuosuoomwmz e a * mmwa .onooq mouoamnmww,mwumuohdofihmuo: « x k « mnwa .wnooq mofifiafia mammoawouowz « s k * mmmH .osomq masofinaww.msuonmoaoqm « a * wmma .onooa mamooosmm mamououm « a « mmmfl .onooq mnamnmwo0HHom‘momoumum « « * mnma .onooq ouooao mommuwum « x a « mnwa .onooq oumosmowxoamsm mouummoom « « x « mcmH .uuwfium moomwummwmm monummoom « mead .uoaafiz mouoofia mououmochu « a « wmma .oaoog moumosoofi>oun mauouooawu omofiooaoumum wuoaommmoz OZHQQmmm ZOHHmDMm wscfiuas oaafiuummmw> mommao> mouoaumam mnemow mooamowmw wuonamH msHmuUNz mason: moaaoaumfimam mason moHHmaumHmwm aaaaa maaamaumamam amm>a>.MNdouam msumaonom mayo“: mHquB mfiuomz mowowaooa mauth aaeusaa wanes: moowaowaauaoamm> mumosmom maahsnfin moonsuoa msooawon A.w.uaoov omoaumaoumoaahnm a.s..ao.V m manna 38 The sequences of deciduous-tooth shedding was inferred in many pteropodids (Leche, 1878), but, as with permanent-tooth eruption, few specimens were examined. More often, sequences were determined from a series of one particular species (Miller, 1896; Reeder, 1953; Stains and Baker, 1954; Stegeman, 1956; Dorst, 195UM; Friant, 1963; Nelson, 1966; Fenton, 1970; Phillips, 1971; Birney and Timm, 1975). Series permitted authors to determine objectively the shedding sequence (Table 5). Deciduous-tooth morphology was described for many chirOpterans (Table 5). Contributing voluminously were Leche (1875, 1877, 1878), Miller (1896, 1907), Dorst (1949, 1957b), Friant (1963), Nelson (1966), and Phillips (1971). Spillman (1927), Matthews (1950), Reeder (1953), Stains and Baker (1954), Stegeman (1956), Jones (1967), Yoshiyuki (1968), and Birney and Timm (1975) determined the morphology of the deciduous teeth for individual species. The maximum deciduous dentition for Myotis, fide Miller (1907), is i %E%-, C'%E% , p %E%'= 22 . The deciduous dentition in M, fortidens and M, occultus may be diver- gent because of variability in the permanent dentition (Hall and Kelson, 1959; Mumford, 1963; Findley and Jones, 1967); this condition in neither species has been examined. Milk teeth of chiropterans are curved Spicules, usually postero-lingually directed, the function of which is to assist the neonate to cling to the nipple of the mother. The permanent dentition of M} albescens is definitively 39 documented (Miller, 1907; Hall and Kelson, 1959), the formula of which is Volant juveniles have fully erupted permanent teeth in M, 122;: fgggg (Fenton, 1970). Stegeman (1956) observed that the deciduous teeth were totally replaced by permanent teeth at eight weeks post- partum in M. lucifugus. The sequence of milk-tooth loss in M, lucifugus is 11 , p4 , 3 2 12 , i3 , p4 , c1 , p3 , c1 , p , i , i3 (Stegeman, 1956; Fenton, 1970). The sequence of permanent-tooth eruption in M, lucifuggs is 11,12,13,C1,P4,P4,M1,M2,P2,C1,M1,M2,P2,M3, 2 3 I , I , M3 , P3 , P3 (Fenton, 1970). APPENDIX C 40 APPENDIX C Figure 3. Location of Mendez, Ecuador. APPENDIX D APPENDIX D PROCEDURE FOR PREPARING SKULLS USING ALIZARIN RED S AND KOH Myotis albescens individuals were transferred to 30 percent ethanol to harden the jaw musculature. Hardened specimens were placed in 1 percent KOH (aqueous) until the jaw musculature was translucent and the dentary, premaxillary, and maxillary bones were visible. Cleared specimens were placed in an Alizarin Red S solution until the musculature became red. The Alizarin Red S solution contained 0.1 gm Alizarin Red S, 10 ml KOH (1 percent aqueous), and 50 m1 H200 Dyed specimens were transferred to KOH (1 percent aqueous) until the musculature became translucent again. All bones and teeth remained red. Stained specimens were placed in a solution of 50 percent KOH (1 percent aqueous) and 50 percent glycerine until the Specimen sank. The specimens were transferred to pure glycerine. Thymol was added to retard mold development. 41 APPENDIX E APPENDIX E PHOTOGRAPHS OF DECIDUOUS TEETH AND JAW MORPHOLOGY IN MYOTIS ALBESCENS Figure 4. Photographs of upper deciduous dentition 42 45 Figure 5. APPENDIX E PHOTOGRAPHS OF DECIDUOUS TEETH AND JAW MORPHOLOGY IN MYOTIS ALBESCENS Figure 6. Photographs of jaw morphology A. Lower jaw, complete deciduous dentition (UNC-W E301F) B. Upper jaw, complete deciduous dentition (UNC-W E301F) C. Lower jaw, partial eruption of permanent teeth and shedding of deciduous teeth (UNC-W E225) D. Upper jaw, partial eruption of permanent teeth and shedding of deciduous teeth (UNC-W E225) 46 47 Figure 6. APPENDIX E PHOTOGRAPHS OF DECIDUOUS TEETH AND JAW MORPHOLOGY IN MYOTIS ALBESCENS Figure 7. Photographs of jaw morphology E. F. G. H. Lower jaw, partial eruption of permanent teeth and shedding of deciduous teeth (MSU 23969) Upper jaw, partial eruption of permanent teeth and shedding of deciduous teeth (MSU 23969) Lower jaw, complete permanent dentition (UNC-W E266) Upper jaw, complete permanent dentition (UNC-W E266) 48 49 10 mm Figure 7. LITERATURE CITED LITERATURE CITED Aellen, V. 1970. Catalogue raisonné des chiropteres de la Colombie. Rev. Suisse Zool., 77(1): 1-37. Aisenberg, M. S. 1966. Shedding of the deciduous teeth. Pp. 320-334, lg Orban's oral histology and embryology (H. Sicher, ed.), The C. V. Mbsby Co., St. Louis, xiii + 416 pp. Allen, G. M. 1939. Bats. Harvard Univ. Press, Cambridge, x + 368 pp. Baker, R. H. 1974. Records of mammals from Ecuador. Publ. Mus., Mich. State Univ. Biol. Series, 5(2): 129-146. Birney, E. C., and R. M. Timm. 1975. Dental ontogeny and adaptation in Diphylla ecaudata. J. Mamm., 51: 204-207. Burt, W. H. 1972. Mammals of the great lakes region. Ann Arbor . Paperback, Univ. 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