JOURNAL OF MORPHOLOGY 199:207-221 (1989)

Comparative Morphology and Evolution of the Female Reproductive Tract in Macroglossine (Mammalia, Chiroptera) CRAIG S. HOOD Department of Biological Sciences and The Museum, Texas Tech University, Lubbock, Texas 79409

ABSTRACT Comparative morphological analysis of the female reproduc- tive tract in macroglossine bats was undertaken to test the hypothesis that nectarivory arose at least twice within Old World fruit bats. Given that features of the female reproductive tract are not directly involved in adap- tations for feeding, this data set should provide a test of the monophyly of macroglossine bats. A cladistic analysis of variation in the structure of the , oviducts, , and external genitalia supports the hypothesis that has developed a nectar-feeding habit independent of other macroglossine genera. Most of the variation in female reproductive organs among pteropodids is found in the development of derived external and in- ternal features of the uterus. Fusion of uterine cornua, expansion of the common uterine body, and elaboration of the cervical region are found in a group which includes species ofPteropus, , , and the ma- croglossines (excluding Megaloglossus). Results of this study are concordant with independent data sets, thus providing a phylogenetic framework to eval- uate critically structural and functional design in the evolution ofpteropodid feeding mechanisms.

One of the most challenging problems in elongated and protrusible tongue. However, evolutionary biology is the understanding of most of these features (except those of the evolutionary change in the form and func- tongue and hyoid region) are not unique to tion of complex anatomical systems. In re- macroglossine bats, also occur in other pter- cent years, the fields of functional and evo- opodids that do not feed on nectar (Ander- lutionary morphology have been redirected sen, '12). by incorporating phylogenetic methods as Features of the female reproductive sys- tools to identify and interpret structural and tem have proven useful in assessing evolu- functional design (Lauder, '81, '82; Liem and tionary relationships within and among Wake, '85). This approach has been success- families (Wimsatt and Enders, '80; Luckett, fully applied to the study of feeding mech- '80; Hood and Smith, '82, '83). This report anisms in actinopterygian fish (e.g., Lauder, describes the system in pteropodid bats, as- '83; Schaefer and Lauder, '86) and pletho- sesses the monophyly of the subfamily Ma- dontid salamanders (e.g., Lombard and Wake, croglossinae, evaluates the fit of macroglos- '86; Wake and Larson, '87). sine bats within the larger context of the The chiropteran family Pteropodidae in- family Pteropodidae, and tests of concord- cludes 44 genera and about 173 species (Fig. ance among independent data sets. 1; Koopman, '84). Bats of the subfamily Ma- croglossinae have long been recognized as MATERIALS AND METHODS members of a monophyletic group on the ba- All specimens were collected in the wild sis of their adaptations to a nectarivorous (Table 1). The anatomical relationships of diet (Dobson, 1875; Andersen, '12; Koop- female reproductive organs and their asso- man, '84). Morphological adaptations asso- ciated with this highly specialized food habit Dr. Craig S. Hood is now at Dept. of Biological Sciences, Loyola include an elongated rostrum, modified University, New Orleans, LA 70118. Address reprint requests braincase, reduced dentition, and a highly there.

© 1989 ALAN R. LISS, INC. 208 C.S. HOOD

' | ' Notoplerine Subfamily Subfamily Eonycterine Croup Macroglossinae Group |

Subfamily Macroglossinae

Family Pteropodidae

Rousen'ine Section Epomophorine Section

Fig. 1. Phylogenetic relationships of the higher tax- onomic groups ofpteropodid bats implied by traditional classifications (after Andersen, '12). ciated supporting membranes were ascer- processed for SEM by fixation with 2% glu- tained by gross dissection at the time of cap- taraldehyde in 0.1 M phosphate buffer at pH ture and excision of tissues, or from dissection 7.2, dehydration, drying in a Parr 4770 crit- of specimens that were collected and pre- ical-point dryer, and gold-pallidium coating served intact. Whole reproductive tracts were at 300 A with a Technics Hummer V Sputter excised and fixed for gross anatomy, histol- Coater. They were observed with a Hitachi ogy, and scanning electron microscopy. S-570 scanning electron microscope at 20 kV. Voucher specimens have been deposited in Phylogenetic relationships were recon- the collections of the American structed using cladistic methods, with out- Museum of Natural History; Carnegie Mu- group comparison and parsimony (Kluge and seum of Natural History; Museum of Com- Farris, '69; Watrous and Wheeler, '81; Far- parative Zoology, Harvard University; Nat- ris, '82; Maddison et al., '84; Smith and Hood, ural History Museum, Los Angeles County; '84). Outgroups examined included repre- Thailand Institute of Technology and Re- sentatives from all bat families except the search; and The Museum, Texas Tech Uni- Craseonycteridae, Furipteridae, and Myzo- versity. podidae. Data from the literature were used Tissues were fixed in 10% buffered for- to determine distribution of character states malin or Boulin's solution and then pro- in other mammalian orders. cessed through paraffin, serially sectioned at 6—10 (Jim, and stained with Mallory's Triple RESULTS Stain or Gomori's One Step Trichrome Gross morphology and external genitalia Method (Humason, '72; Thompson, '66; Hood The overall anatomical arrangement of the and Smith, '83). Selected reproductive tracts ovaries, oviducts, and uterus in pteropodid BAT REPRODUCTIVE TRACT MORPHOLOGY 209 TABLE 1. List of specimens examined in this study1 ids, and molossids (see also Wood Jones, '17; Family Pteropodidae Matthews, '41; Madkour, '76). Together with pteropodids, these bat families share a Subfamily Pteropodinae broadly flattened genital tubercle and cli- Rousettine-section amplexicaudatus (5) toris, and an overall transverse disposition admirattitatum (1) of the . In contrast, the external gen- Pteropus hypomelanus (2) italia of noctilionids, mormoopids, phyllos- Pteropus neohibernicus (3) tomids, thyropterids, and natalids are dra- Pteropus temmincki (1) Dobsonia moluccesis (2) matically modified (see also, Wood Jones, '17; Dobsonia praedatrix (2) Wimsatt and Enders, '80). These bat fami- Epomorphorine-section lies show an elongation of the vulva in an franqueti (3) anteroposterior direction, an elongate cli- Hypsignathus monstrosus (2) pusillus (4) toris, prominent minora, and poorly Cynopterine-section developed postanal-circumanal folds. The sphinx (6) anteroposterior development of the vulva Cynopterus horsfieldi (1) appears to be a derived feature within euth- Balwnycteris maculata (2) Nyctimene albiventer (5) erian , a similar evolutionary trend Nyctimene vizcaccia (1) being found only in the primates. Subfamily Macroglossinae spelaea (6) Ovarian morphology Megaloglossus woermanni (8) minimus (24) The ovaries of pteropodids are either Macroglossus sobrinus (3) spherical or slightly elongate and their his- australis (1) tology is typical of that of other mammals. melanops (6) macdonaldi (3) In all pteropodids examined, both ovaries contain a variety of follicular types and are Wos. in parentheses represent sample sizes. equally functional, with ovulation alternat- ing between sides. Extensive networks of bats is equivalent to that found in other bat blood vessels are found in the ovarian hilus, families and in eutherians generally. The the mesenteries supporting the oviduct, and free uterine horns are long in pteropodids the cranial end of the uterus in many of the and their ovaries lie more superior than those taxa examined. This histological arrange- of emballonurids, rhinolophids, vesperti- ment allows for direct vascular (veno-arte- lionids, molossids, and phyllostomoids. The rial) shunts between these organs. Such a pteropodid arrangement is similar to that system occurs in Pteropus giganteus and its found in eutherians that also possess prim- vascular shunts mediate asymmetrical ovi- itive (duplex) uterine morphologies (Der- ductal and uterine reactions (Marshall, '49; moptera, Rodentia; Mossman, '77). '53). Although the present study was not de- A major dichotomy in female external signed to investigate questions of reproduc- genitalia exists between Megachiroptera and tive function, histological features of ovar- some families of Microchiroptera. In ptero- ian anatomy suggest that vascular shunts podids, the urogenital orifice is a transverse occur in a wide variety of pteropodid taxa. opening found immediately anterior to the The anatomical relationship of the anus. A raised structure, the genital tuber- to the oviduct and uterus in pteropodids has cle, is directed caudally over the opening and no unusual features compared to those of contains a broad, flattened . The mar- other mammals. In all pteropodids exam- gins of the urogenital orifice are not raised ined, the ovary and oviduct are enveloped to form , but postanal and cir- by an ovarian bursa that is composed of a cumanal folds of unknown homology are pre- and mesosalphinx. Phyllosto- sent. Pteropodid external genitalia are re- moid bats demonstrate a tremendous vari- markably similar to that found in ety of bursal types (Hood and Smith, '83), Cynocephalus (order Dermoptera) and gen-. whereas pteropodids display conservative erally like that of many other eutherians anatomy. According to the terminology of (Robin, 1881; Wood Jones, '17). Mossman and Duke ('73), pteropodids are Within Microchiroptera, variations in these characterized as having a complete bursa, features occur in emballonurids, rhinopom- with a tiny, slitlike peritoneal opening. The atids, rhinolophids, hipposiderids, nycterids, oviduct wraps around the lateral and cranial megadermatids, vespertilionids, mystacin- aspects of the ovary (lateral recurve type). 210 C.S. HOOD

Oviductal morphology relatively long uterine horns and short com- The oviducts of pteropodids are relatively mon uterine bodies (Fig. 2). In these latter short and regionally differentiated into an families, the common uterine body is pre- infundibulum, preampulla, ampulla, isth- dominantely cervical; thus, the common mus, and junctura. The extramural oviduct, uterine lumen contributes little to gestation as denned by Hood and Smith ('83), contacts of the developing fetus. the cranial end of the uterine horn at its Most families of bats possess histological apex and traverses the uterine wall until it features of the that are typical by opens into the uterine lumen. In many of the mammalian standards. The length and ex- outgroup taxa, the extramural oviduct and tent of the cervix is quite variable among uterine horn have an apical site of contact; bats. In phyllostomoids, emballonurids, examples include emballonurides, rhinolo- rhinopomatids, rhinolophids, hipposiderids, phids, hipposiderids, noctilionids, mormoop- and megadermatids, the cervix constitutes ids, and some phyllostomids. approximately one-third of the total length Vespertilionids and molossids possess an of the uterus, whereas in vespertilionids and uterotubal junction (UTJ) with a prominent mystacinids, it contributes nearly one-half colliculus, whereas rhinolophids, hipposi- of the total length. In these microchirop- derids, megadennatids, and mystacinids have teran families, the portio vaginalis is a low, a small papilla. Phyllostomoids are char- distinctly rounded or cronical mound. In acterized by having a simple UTJ. Embal- phyllostomoids, most rhinolophids, and hip- lonurids do not possess a distinct papilla or posiderids, the portio vaginalis projects cen- colliculus, but have numerous small to me- trally into the , whereas in the re- dium-sized uterine folds that contribute to maining families it projects from the dorsal form a complicated pocketed region. The UTJ wall. in pteropodids is represented by numerous Internally, only some emballonurids (e.g., folds like those found in emballonurids. The Taphozous) and pteropodids have com- number and extent of these folds varies pletely separate uterine lumina that open among pteropodid taxa. However, these as independent cervical canals into the va- variations appear to be one of degree. The gina (Fig. 2). In all other bat families there junction of Rousettus, Hypsignathus, and is a single common uterine lumen and cer- Cynopterus is least elaborate, with folds that vical opening (external os). In most mam- are invested with numerous uterine glands. mals, the cervicovaginal junction is an ab- At the other extreme are species of Dob- rupt and well-defined region located at the sonia, Pteropus, Eonycteris, and Macroglos- external os. However, in some groups, no- sus, which are characterized by having fewer, tably Primates and Chiroptera, the cervi- but longer, folds that greatly constrict the covaginal junction is remarkably variable cranial end of the uterine cornua. In these and complex (cf. Hafez and Jaszczak, '72; taxa, the entire cranial half of the free uter- Hafez, '73; Graham, '73; Kanagawa and ine horns are complicated with endometrial Hafez, '73; Hood and Smith, '83). folds and uterine glands. Variation in external and internal uterine anatomy found in chiropteran families used Uterine morphology for outgroup comparisons was described and phylogenetic implications discussed by Hood General description and outgroup and Smith ('82, '83). External and internal comparisons uterine morphology in pteropodid bats is In all chiropteran families examined as considered below. outgroups in this study, the free uterine horns are composed of histologically well-defined Rousettines myometrial and endometrial layers. The Three genera, Rousettus, Pteropus, and common uterine body is often found to con- Dobsonia, of Andersen's ('12) Rousettine- sist of two distinct regions: a continuation section were examined. Externally, the uterus of the endometrial-lined gestational uterus of Rousettus amplexicaudatus is distinctly and the cervix. In phyllostomoids that pos- V-shaped, with extremely long uterine horns sess large common uterine bodies, the cervix and a short common uterine body (Fig. 3). is limited to the caudal portion of the tract The common body constitutes less than one- and a single large gestational uterine lumen fourth of the total length of the uterus and exists. In contrast, other bat families have consists entirely of the cervix. Cervical ca- BAT REPRODUCTIVE TRACT MORPHOLOGY 211

TAPHOZOUS LONGIMANUS HIPPOSIDEROS DIADEMA

PIPISTRELLUS HESPERUS TADARIDA PLICATA

Fig. 2. Semidiagrammatic frontal sections of female dae). 0V, ovary; OVD, oviduct; OLP, oviductal lamina reproductive tracts in outgroup taxa, including Tapho- propria; UTJ, uterotubaljct.; MYO, ; END, zous (Emballonuridae), Hipposideros (Hipposideridae), ; CS, cervical stroma; CF, cervical folds; Pipistrellus (Vespertilionidae), and Tadarida (Molossi- CL, common uterine lumen; VA, vagina. 212 C.S. HOOD

Fig. 3. Semidiagrammatic frontal sections of female (A) and Hypsignathus (B). Abbreviations as in Figure reproductive tracts in the pteropodid genera Rousettus 2.

nals open into the vagina independently constitute slightly less of the total length of through a short, centrally projecting portio the uterus compared with that of P. neohi- vaginalis. bernicus. The common body is short and broad Observations on Rousettus leschenauiti and possesses a distinct myometrial layer. confirm those previously reported (Gopalak- Cervical canals are narrow and open inde- rishna and Choudhari, '77; Karim et al., '79), pendently into the vagina by way of a low, but contradict the report by Karim ('75) that rounded portio vaginalis. No median vagi- the portio vaginalis is a hemispherical bulb. nal septum is present. In specimens examined in the present study, The uterus of one specimen of Pteropus the portio is a short, centrally projecting admiraltitatum examined presented a some- structure. what different form. In this species, the uter- The form of the uterus varies considerably ine horns taper distinctly, being broadest at among species of Pteropus. The uterus of P. their bases (Fig. 4). The common uterine body neohibernicus is Y-shaped, has a long comua, is slightly longer than that observed in other and a short common uterine body (Fig. 4) species of Pteropus, and the uterine horns which constitutes nearly one-third of the to- appear shorter. The anatomical relationship tal length of the uterus and consists only of of the cervical canals to the vagina is similar cervical tissue. The lumina of its cervical to that found in P. hypomelanus and P. tem- canals are narrow and open into the vagina mincki. independently. The portio vaginalis is a The uteri ofDobsonia moluccensis andZ). scarcely detectable rounded mound. In con- praedatrix do not differ; D. moluccensis is trast to all other pteropodids examined, the described (Fig. 4). The uterus of D. moluc- vagina of P. neohibernicus has a muscular censis is Y-shaped, with long uterine horns median septum that divides it into two ca- and a short, broad, common uterine body that nals for about one-third of its length. This represents about one-third to nearly one-half septum is composed of striated muscle that of the total length of the uterus. Uterine lu- also invests the vaginal wall. mina within the common body are entirely The cervices ofPteropus hypomelanus and cervical. The two cervical canals are flat- P. temmincki do not differ (Fig. 4). In these tened in transverse section, and open inde- two species, the uterine horns are long but pendently into the vagina through a low, BAT REPRODUCTIVE TRACT MORPHOLOGY 213

Fig. 4. Semidiagrammatic frontal sections of female (C),andP. hypomelanus (D). Abbreviations as in Figure reproductive tracts in the pteropodids Dobsonia mol- 2. uccensis (A), Pteropus neohibernicus (B), P. temmincki 214 C.S. HOOD

Fig. 5. Semidiagrammatic frontal sections of female maculata (0, and Nyctimene albiventer (D). Abbrevi- reproductive tracts in the cynopterines Cynopterus ations as in Figure 2. brachyotis (A), niphanae (B), Balionycteris BAT REPRODUCTIVE TRACT MORPHOLOGY 215 projecting portio vaginalis. These features cal canals are narrow and lumina flattened. generally resemble those found in P. hypo- Megaerops shares with Cynopterus an enor- melanus and P. temmincki. mous portio vaginalis that fills most of the cranial end of the vagina. Cervical ectopism Epomophorines was noted in one specimen, but did not ap- Three genera, Epomops, Hypsignathus, and pear to be as extensive as that found in C. Micropterus, of Andersen's ('12) Epomophor- sphinx. ine-section were examined. The uteri of all The uteri of Nyctimene albiventer and three genera are qualitatively equivalent; N. uizcaccia are qualitatively equivalent; N. Hypsignathus monstrosus is illustrated in albiventer is illustrated (Fig. 5). The uterus Figure 3. In these taxa the uterus is V-shaped, of N. albiventer is broadly Y-shaped, with with long horns and a slightly rounded com- long horns and a moderately long, broad mon uterine body that measures only one- common body which measures nearly one- fourth of the total length of the uterus. half of the total length of the uterus. Inter- nally the cervical canals are extremely long, Cynopterines extending into the free uterine horns. The The uteri of four genera of Andersen's ('12) caudal half of the canals possess large, com- Cynopterine-section were examined. Balion- plicated cervical folds that make this area ycteris maculata has a Y-shaped uterus, with an extremely complex pocketed region. Cer- long horns and a short, round, common body, vical canals open into the vagina by way of which constitutes from one-fourth to one-third a large, projecting portio vaginalis. The form of its total length (Fig. 5). A small portion of the portio vaginalis in Nyctimene approx- ofgestational, endometrial-lined uterine lu- imates that found in Cynopterus and Me- men is included in this common body. The gaerops in relative size and shape. The cer- cervical canals are narrow, laterally flat- vicovaginal junction, although complicated tened, and supported by a histologically well- by the extensive cervical folds within the defined cervical stroma (Fig. 6). A prominent portio vaginalis, is abrupt; typical vaginal portio vaginalis projects into the vagina as epithelium lines the fornices of the cranial a conical mound distinguishing Balionyc- end of the vagina. teris (and other cynopterines) from all other pteropodids examined. The portio is so large Subfamily Macroglossinae that nearly one-half of the extent the cer- vical canals are contained within this struc- The uteri of all six genera (Eonycteris, ture. The cervicovaginal junction is vari- Macroglossus, Megaloglossus, Melonycteris, able, and is not always found at the external Notopteris, and Syconycteris) of the subfam- os. within the cervical ily Macroglossinae were examined. The canals of one specimen is illustrated in Fig- uterus of Megaloglossus woe.rm.anni is dis- ure 6. tinctly V-shaped, with extremely long horns The uteri of Cynopterus horsfieldi and C. and a short common body (Fig. 7). The com- sphinx are qualitatively equivalent (Fig. 5). mon body measures only about one-fourth of The uterus of C. sphinx is Y-shaped, with the total length of the uterus and is slightly long uterine horns and a short common uter- rounded in shape; cervical canals are short ine body that represents about one-fourth of and narrow, opening independently by way the total length of the uterus; cervical canals of a barely noticeable portio vaginalis. In all open independently into the lateral fornices specimens examined, the cervicovaginal of the vagina by way of an enormous portio junction was abrupt, with cervical histolog- vaginalis that fills most of the cranial end ical characteristics ending at the external os of the vagina. The cervicovaginal junction of each . Uterine histomor- in Cynopterus is extremely complex. Cervi- phology in Megaloglossus is like that found cal mucosa is ectopic, covering the vaginal in Rousettus and representatives of the surfaces of the portio and lining the fornices. Epomophorine-section. The uterus of Megaerops niphanae is Y- The uterus of Eonycteris is Y-shaped, with shaped, with a less acute angle between horns moderately short horns and a long common than is found in other cynopterines (Fig. 5). body which measures nearly one-half the to- The common body is short, representing only tal length of the uterus (Fig. 7). A median about one-fourth the total length of the groove is found on the ventral external sur- uterus. As in other cynopterines, the cervi- face of the common body, and is especially Figure 6 BAT REPRODUCTIVE TRACT MORPHOLOGY 217 prominent near the junction of the free uter- Phylogenetic analyses ine horns. This feature appears to represent The female reproductive tract of the pter- an enlargement of the cervical canals and opodids examined is relatively conservative. not a superficial fusion of the cornua, and Table 2 lists the distribution of character distinguishes Eonycteris and other macrog- states among the pteropodid taxa examined. lossines (except Megaloglossus) from all other Four characters show derived character pteropodids. The cervical canals are mod- states. Character 1, degree of fusion of ex- erately long and possess numerous long cer- ternal uterine anatomy, may be character- vical folds, which open independently into ized in three character states (0,1,1'). Char- the vagina by way of a low, but distinct, acter state 0 is characterized by extremely portio vaginalis. long uterine horns and a short common body The uteri ofSyconycteris australis and two (one-fourth or less of the total length of the species of Macroglossus, M. minimus and M. uterus) and represents the primitive condi- sobrinus, are qualitatively equivalent; M. tion for the family, having been found in minimus is illustrated (Fig. 7). The uterus several eutherian outgroups (Dermoptera, ofM. minimus is Y-shaped, with moderately Rodentia, primitive Primates, and Insecti- short horns and a long common body. Ma- vora). Microchiropteran outgroups have var- croglossus shares with Eonycteris an exter- iously derived external morphologies, but nally visible groove on the ventral surface among these, Taphozous (family Emballon- of the common body, but the common body uridae) nearly approaches this state. De- is further modified by being much enlarged rived character state 1 represents fusion of and round or pear-shaped. Internally, the uterine horns resulting in a prominent com- cervical canals are relatively long and pos- mon uterine body (one-third of the total sess numerous greatly enlongated cervical length of the uterus). Character state 1' rep- folds, which make this region appear to pos- resents uterine fusion to its highest degree sess large pockets that are lined with cer- in pteropodids, resulting in moderately short vical mucosa. Cervical canals open indepen- uterine horns and a large common body (one- dently at the edges of a low, rounded portio half of the total length of the uterus). vaginalis. In all specimens examined, the Character 2 describes modification of the cervicovaginal junction is abrupt. common uterine body and includes three The uteri of Melonycteris melanops and states (0, 2, 2'). Character state 0, found in Notopteris macdonaldi are barrel-shaped, outgroups and many pteropodids, is the sim- with moderately short horns and a large, ple fusion of the uterine cornua resulting in expanded common body which measures a smooth, tubular, common uterine body. nearly one-half of the total length of the Character state 2 is the presence of a median uterus (Fig. 7). Melonycteris and Notopteris groove on the ventral surface of the common share with Eonycteris, Macroglossus, and body. This groove reflects modification of how Syconycteris a median groove on the ventral external fusion has occurred; the cervical ca- surface of the common uterine body. The nals have enlarged in diameter and are ev- greatly expanded common body in Melon- ident externally. Character state 2' is the ycteris and Notopteris appears to be a con- lateral expansion and enlargement of the tinuation of that specialization observed in cervical canals to form a massive, pear- to Macroglossus and Syconycteris. Internally, barrel-shaped common body. the cervical canals are greatly expanded, and Character 3 describes modification of the large cervical folds form a complicated net- portio vaginalis and includes three states (0, work of pocketed spaces within the body. No 3,3'). Character state 0, found in many euth- portio vaginalis could be distinguished; cer- erians and in most microchiropteran out- vical canals open into the vagina by way of groups is a low, rounded portio vaginalis. independent openings that are widely sep- Character state 3 is enlargement of this arated. structure resulting in a portio that is prom- inent, conical, and projects centrally into the vagina. One-third to one-half of the length Fig. 6. Histology of the caudal end of the uterus in of the cervical canals are contained within Balionycteris maculata (A, B, C, D). Cervical canals are the portio. Character state 3' is the contin- laterally flattened (C, D) and surrounded by a muscular ued modification of this feature (more than layer (MS), that is continuous with the myometrium. Cervical lamina propria (CLP) supports cervical folds. one-half of the length of the cervical canals Bar =0.1 mm for all photographs. are contained within the portio), resulting 218 C.S. HOOD

ovo

Fig. 7. Semidiagrammatic frontal sections of female melanops (C), and Macroglossus minimus (D). Abbre- reproductive tracts in the macroglossines Eonycteris viations as in Figure 2. spelaea (A), Megaloglossus woermanni (B), Melonycteris in a massive portio vaginalis that fills most tremely long cervical canals that extend into of the cranial end of the vagina. the externally free uterine horns. Character 4 describes the length and ex- tent of the cervix and includes two states (0, DISCUSSION 4). Character state 0, found in outgroups and Phylogenetic implications most pteropodids, represents the mainte- Comparisons with outgroups shows that nance of a cervix within the common uterine pteropodid bats have retained a relatively body. Character state 4 is presence of ex- primitive duplex uterine morphology. How- BAT REPRODUCTIVE TRACT MORPHOLOGY 219

TABLE 2. Distribution of character states for female reproductive data.1 _____

Characters

Taxa 1 2 3 4

Outgroups 0 0 0 0 Rousettus 0 0 0 0 Epomops 0 0 0 0 Hypsignathus 0 0 0 0 Micropteropus 0 0 0 0 Melaloglossus 0 0 0 0 Balionycteris 0 0 3 0 Cynopterus 0 0 3' 0 Megaerops 0 0 3' 0 Pteropus 1 0 0 0 Dobsonia 1 0 0 0 Fig. 8. Cladogram of female reproductive histomor- Nyctimene 1 0 3' 4 phology. Taxa marked with asterisks had been previ- Eonycteris 1 2 0 0 ously included within the subfamily Macroglossinae. Macroglossus 1 2' 0 0 Characters and character states are described in the Syconycteris 1 2' 0 0 text. Melonycteris 1 2' 0 0 Notopteris 1 2' 0 0 'See text for explanation of character coding. of the common uterine body (2). Macroglos- sus, Syconycteris, Melonycteris, and Notop- teris are distinguished from Eonycteris by a ever, the external and internal morphology further derived condition (2'). The synapo- of the uterus varies widely among ptero- morphy scheme presented here is not fully podid bats. This suggests that uterine mor- resolved, but only two homoplasious events phology has undergone more evolution within were noted (if the character state tree for bat families than in other eutherian orders character 3 is 0 -> 3 -> 3'). (Hood and Smith, '82; '83). The results of the phylogenetic analysis of Phylogenetic relationships of pteropodid female reproductive morphology conflict with bats based on features of the female repro- traditional views of the higher classification ductive tract are presented in Figure 8. Five of pteropodid bats in several ways (Figs. 1, genera, Rousettus (Rousettine-section), 8). First, the monophyly of the nectar-feed- Epomops, Hypsignathus, Micropteropus ing subfamily Macroglossinae is rejected. (Epomophorine-section), and the macroglos- Megaloglossus is not a member of the clade sine Megaloglossus, have retained primitive that includes other macroglossines, but has female reproductive features. The remain- retained primitive reproductive features and ing taxa are members of two clades. One is associated with non-nectar-feeding taxa. group, which includes the cynopterines Bal- If this hypothesis is correct, then nectarivory ionycteris, Cynopterus, and Megaerops, is has evolved at least twice within the family recognized by a modification of the portio Pteropodidae. Second, the phylogenetic vaginalis (3). Within the group, a further placement of macroglossine bats (excluding derived character state (3') unites the gen- Megaloglossus) within the context of the era Cynopterus and Megaerops. family is predicted as a set of nested rela- A second monophyletic group, including tionships with the frugivorous genera Pter- Pteropus, Dobsonia, Nyctimene, and the ma- opus, Dobsonia, and Nyctimene. These sis- croglossines (excluding Megaloglossus) is ter-group relationships provide a supported by six derived character states. phylogenetic framework for future studies. Within this assemblage are several nested Third, Andersen's ('12) Epomophorine- and subgroups. Nyctimene is associated with Cynopterine-sections are not contradicted by Eonycteris, Macroglossus, Syconycteris, Me- the results of the present study. Epomo- lonycteris, and Notopteris by a derived char- phorines have retained primitive female re- acter state (!'), but also shares an appar- productive features, whereas cynopterines ently convergent character state (3') with are supported as a monophyletic group on Cynopterus and Megaerops. The macroglos- the basis of shared derived features. sines (excluding Megaloglossus) represent a The phylogenetic implications of this study monophyletic group based on a modification are highly concordant with those obtained 220 C.S. HOOD by recent immunoelectrophoretic and chro- morphology, it will be difficult to provide mosomal studies (Haiduk et al., '80, '81, '83; strong explanations for the functional sig- Haiduk, '83). Thus a general hypothesis of nificance of variation in uterine morphology phylogenetic relationship for pteropodid bats among bats. based on biochemical, chromosomal, and an- atomical data predicts that 1) nectarivory ACKNOWLEDGMENTS must have evolved at least twice within the I thank Drs. R.J. Baker, R.K. Chesser, family, 2) macroglossines (excluding Megal- C. Jones, J.K. Jones, Jr., and M. Willig for oglossus) have nested sister-group relation- critically reviewing earlier drafts of this pa- ships with Pteropus, Dobsonia, and Nyoti- per. C. Gans and four anonymous reviewers mene, and 3) epomorphorines and contributed important critiques that im- cynopterines are monophyletic groups. proved the manuscript. For aid in fieldwork I gratefully acknowledge M.W. Haiduk, K. Functional explanations of reproductive McBee, C.J. Phillips, D. Pumo. L.W. Rob- tract evolution bins, D.A. Schlitter, J.D. Smith, K.M. Stu- What features of reproduction could ex- dhoime, S.L. Williams, and S. Yenbutra. R.L. plain the variation in uterine morphology Honeycutt (MCZ), K.F. Koopman (AMNH), observed among pteropodid bats? Wimsatt and D.A. Schlitter (CMNH) kindly allowed ('75, '79) and Mossman ('77) have discussed me to dissect specimens housed in museum aspects of reproductive biology that appar- collections. Support was provided by the In- ently are correlated with uterine morphol- stitute of Museum Research, Carnegie Mu- ogy in mammals. The most important and seum of Natural History, Hofstra Univer- consistent correlation is that of litter size. sity, Loyola University Faculty Research Mammals with short, bicornuate and sim- Grant, Sigma Xi, American Society ofMam- plex uteri carry only one or a few young, malogists, an Albert R. and Alma Shadle whereas longer, duplex uteri characterize Fellowship, and an Ernst Mayr Grant (Mu- taxa with large litters. Bats represent a ma- seum of Comparative Zoology). This paper jor exception to this "rule." The vast major- represents part of a Ph.D. dissertation com- ity of bat species, including pteropodids, pro- pleted at Texas Tech University. duce litters of one (many vespertilionids have LITERATURE CITED twins), whereas uterine morphology varies Andersen, K. (1912) Catalogue of the Chiroptera in the from simplex to duplex (Luckett, '80; Hood Collection of the British Museum. London: British and Smith, '82). Adaptation towards a smaller Museum (Nat. Hist). litter size does not explain the evolution of Beck, A.J., and B.L. Lim (1973) Reproductive biology of Eonycteris spelaea Dobson (Megachiroptera) in West uterine morphology in bats. Malaysia. Acta Trop. (Basel) 30:251-261. Anatomical and physiological asymmetry Bhat, H.R., M.A. Sreenivasan, and P.G. Jacob (1980) is a striking feature of many chiropteran Breeding cycle of Eonycteris spelaea (Dobson, 1871) species (Wimsatt, '79; Rasweiler, '79, '82; (Chiroptera, Pteropodidae, Macroglossinae) in India. Mammalia 44:343-347. Hood and Smith, '83). Unilateral oviductal Dobson, G.E. (1875) Conspectus of the suborders, fam- and uterine reactions have been described ilies, and genera of Chiroptera arranged according to in some phyllostomoids (Rasweiler, '78, '79), their natural affinities. Ann. Mag. Nat. Hist. Ser. 4, emballonurids (Rasweiler, '82), and ptero- 16:345-357. Farris, J.S. (1982) Outgroups and parsimony. Syst. Zool. podids (Marshall, '49, '53). Although the 37:328-334. widespread distribution of these features Gopalakrishna, A., and P.N. Choudhari (1977) Breeding would suggest their independent evolution habits and associated phenomena in some Indian bats. in several families, they may have value in Part 1.—Rousettus leschenauiti (Desmaret)—Mega- chiroptera. J. Bombay Nat. Hist. Soc. 74:1-16. explaining some aspects of uterine variation Hafez, E.S.E., and S. Jaszczak (1972) Comparative anat- within particular groups. Few data are omy and histology of the cervix uteri in non-human available on pteropodid reproductive biol- primates. Primates 23:297-314. ogy. However, local unilateral reactions Haiduk, M.W. (1983) Evolution in the Family Ptero- podidae (Chiroptera: Megachiroptera) as Indicated by which alternate between sides have been Chromosomal and Immunoelectrophoretic Analyses. found in species of Pteropus, Eonycteris, and Ph.D. Thesis, Texas Tech University; Lubbock. Macroglossus (Marshall, '49, '53; Beck and Haiduk, M.W., L.W. Robbins, R.L. Robbins, and Lim, '73; Rasweiler, '79; Bhat et al., '80; Hood D. A. Schlitter (1980) Karyotypic studies of seven spe- cies of African megachiropterans (Mammalia: Ptero- and Smith, '84). Until we understand the podidae). Ann. Carnegie Mus. Nat. Hist. 49:181-191. nature of the association of various derived Haiduk, M.W., R.J. Baker, L.W. Robbins, and or unique reproductive features with uterine D.A. Schlitter (1981) Chromosomal evolution in Af- BAT REPRODUCTIVE TRACT MORPHOLOGY 221

rican Megachiroptera: G- and C-band assessment of (1984) Outgroup analysis and parsimony. Syst. Zool. the magnitude of change in similar standard karyo- 33:83-103. types. Cytogenet. Cell Genet. 29:221-232. Madkour, G. (1976) External genitalia and mammary Haiduk, M.W., L.W. Robbins, and D.A. Schlitter (1983) glands of Egyptian female bats. Zool. Anz. 297:62-66. Chromosomal banding studies and their systematic Marshall, A.J. (1949) Pre-gestational changes in the giant implications in African fruit bats (Chiroptera: Pter- fruit bat, (Pteropus giganteus), with special reference opodidae). Ann. Mus. Voor Midden-Africa, Belgium, to an asymmetrical endometrial reaction. Proc. Linn. 257-259. Soc. London 762:26-36. Hood, C.S., and J.D. Smith (1982) Cladistical analysis Marshall, A.J. (1953) The unilateral endometrial reac- of female reproductive histmorphology in phyllosto- tion in the giant fruit bat (Pteropus giganteus Brun- matoid bats. Syst. Zool. 32:241-251. nich). J. Endocrinol. 9:42^14. Hood, C.S., and J.D. Smith (1983) Histomorphology of Matthews, L.H. (1941) Notes on the genitalia and re- the female reproductive tract in phyllostomoid bats. production of some African bats. Proc. Zool. Soc. Lond. Occas. Papers Mus. Texas Tech Univ. 86:1-38. Ser.B 222:289-346. Hood, C.S., and J.D. Smith (1984) Histology of a sexually Mossman, H.W. (1977) Comparative anatomy. In dimorphic integumentary gland in Macroglossus la- R.M. Wynn (ed): The Biology of the Uterus. New York: gochilus (Chiroptera: Pteropodidae). J. Mamm. 65:1- Plenum Press, 2nd edition, pp. 19—34. 19. Mossman, H.W., and K.L. Duke (1973) Comparative Humason, G.L. (1972) Tissue Techniques. San Morphology of the Ovary. Madison: Univ. Wisconsin Francisco: W.H. Freeman. Press. Kanagawa, H., and E.S.E. Hafez (1973) Morphology of Rasweiler, J.J., IV (1978) Unilateral oviductal and uter- cerivix uteri of Rodentia, Carnivora, and Artiodac- ine reactions in the little bulldog bat, Noctilio aibi- tyia. Acta Anat. 84:118-128. ventris. Biol. Reprod. 29:467^92. Karim, K.B. (1975) Utero-vaginal junction in the Indian Rasweiler, J.J., IV (1979) Early embryonic development fruit bat, Rousettus leschenauiti (Desmaret). Curr. Sci. and implantation in bats. J. Reprod. Fertil. 56:403- 44:706, 707. 416. Karim, K.B., W.A. Wimsatt, A.C. Enders, and A. Go- Rasweiler, J.J., IV (1982) The contribution of observa- palakrishna (1979) Electron microscopic observations tions on early in the little sac-winged bat, on the yolk sac of the Indian fruit bat, Rousettus les- Peropteryx kappleri, to an understanding of the evo- chenauiti (Desmaret) (Pteropidae). Anat. Rec. 295:493- lution of reproductive mechanisms in monovular bats. 509. Biol. Reprod. 27:681-702. Kluge, A.G., and J.S. Fan-is (1969) Quantitative phy- Robin, H.A. (1881) Recherques anatomiques sur les letics and the evolution ofanurans. Syst. Zool. 28:1— Mammiferes de 1'ordre des cheiropteres. Ann. Sci. Nat., 32. Ser. 6, Zool. 22:1-180. Koopman, K.F. (1984) Bats. In S. Anderson and Schaefer, S.A., and G.V. Lauder (1986) Historical trans- J.K. Jones, Jr. (eds): Orders and Families of Recent formation of functional design,: evolutionary mor- Mammals of the World. New York: John Wiley and phology of feeding mechanisms in loricarioid cat- Sons, pp. 145-186. fishes. Syst. Zool. 35:489-508. Lauder, G.V. (1981) Form and function: Structural anal- Smith, J.D., and C.S. Hood (1984) Genealogy of the New ysis in evolutionary morphology. Paleobiology 7:430- World nectar-feeding bats reexamined: a reply to Grif- 442. fiths. Syst. Zool. 33:435^60. Lauder, G.V. (1982) Historical biology and the problem Thompson, S.W. (1966) Selected Histochemical and His- of design. J. Theor. Biol. 97:57-67. topathological Methods. Springfield: Charles C. Thomas Lauder, G.V. (1983) Functional design and evolution of Publ. the pharyngeal jaw apparatus in eutelostean fishes. Wake, D.B., and A. Larson (1987) Multidimensional an- Zool. J. Linn. Soc. 77:1-38. alysi of an evolving lineage. Science 238:42—48. Liem, K.F., and D.B. Wake (1985) Morphology: current Watrous, L.E., and Q.D. Wheeler (1981) The out-group approaches and concepts. In M. Hildebrand, D.M. comparison method of character analysis. Syst. Zool. Bramble, K.F. Liem, and D.B. Wake (eds): Functional 30:1-11. Vertebrate Morphology. Cambridge: Belknap Press, Wimsatt, W.A. (1975) Some comparative aspects of im- pp.366-377. plantation. Biol. Reprod. 22:1—40. Lombard, R.E., and D.B. Wake (1986) Tongue evolution Wimsatt, W.A. (1979) Reproductive asymmetry and uni- in the lungless salamanders, family Plethodontidae. lateral pregnancy in Chiroptera. J. Reprod. Fertil. IV. Phylogeny of plethodontid salamanders and the 56:345-357. evolution of feeding dynamics. Syst. Zool. 35:532—551. Wimsatt, W.A., and A.C. Enders (1980) Structure and Luckett, W.P. (1980) The use of fetal membrane data in morphogenesis of the uterus, placenta, and parapla- assessing chiropteran phylogeny. In D.E. Wilson and cental organs of the Neotropical disc-winged bat, Thy- A.L. Gardner (eds): Proceedings of the Fifth Inter- roptera tricolor spix (Microchiroptera: Thyropteridae). national Bat Research Conference. Lubbock: Texas Am. J. Anat. 259:209-243. Tech Press, pp. 245-265. Wood Jones, F. (1917) The genitalia of the chiroptera. Maddison, W.P., M.J. Donoghue, and D.R. Maddison J. Anat. Physiol. 52:36-60.