A new genus and two new species of unarmed hymenolepidid cestodes (Cestoda: Hymenolepididae) from geomyid rodents in Mexico and Costa Rica

Two new cestodes of the family Hymenolepididae are described from two species of rodents of the family Geomyidae collected in Mexico and Costa Rica. One new species of Hymenolepis is described from Cratogeomys planiceps Merriam 1895 from near Toluca, Mexico and another that we allocate to a new genus is described from Heterogeomys heterodus (Peters, 1865) from near Irazú Volcano, Costa Rica. Hymenolepis s. str. includes those Hymenolepididae with an apical organ, with no hooks on suckers or apical organ, and three testes. Hobergia irazuensis n. gen., n. sp. includes a hymenolepidid with an apical organ, unarmed scolex, small pockets termed foveolae, in which the suckers completely retract, and extremely bi-lobed ovary. Multivariate morphometric analysis showed good separation of these species from all other hymenolepidids possessing an apical organ and lacking a well developed rostellum and rostellar hooks in the Nearctic and Neotropical regions. to gravid proglottids. Strobila attenuated and narrowest in neck region, posteriad to scolex. Scolex with four fully developed and separate suckers Each sucker with foveola and associated structures. Foveolae completely contain suckers when suckers are retracted Apical organ, piriform (Fig. 1). Anterior most part of osmoregulatory canals not penetrating apical organ sac. Transverse tubes connect ventral osmoregulatory canals. Genital ducts pass dorsal to osmoregulatory canals. Genital pores dextral, marginal, and unilateral. Cirrus sac, internal seminal vesicle, and external seminal vesicle dorsal to seminal receptacle, ovary, vitelline gland, and Mehlis’ gland. long. Larger hooks of first and third pairs have robust, wide guards. Smaller hooks of first and third pairs, total length, N = 45, 9–13 (11 ± 1) long by N = 46, 1–2 (1.8 ± 0.2) wide at guard. Handle, N = 46, 4–7 (6 ± 1) long, blade, N = 46, 3–5 (4 ± 0.4) long. Smaller hooks of first and third pairs have narrow, more delicate guards. Middle pair of hooks, total length, N = 24, 11–14 (12 ± 1) long by N = 24, 1–2 (1.7 ± 0.2) wide at guard, handle, N = 24, 6–8 (7 ± 1) long, blade, N = 24, 4–6 (5 ± 1) long. Middle pair of hooks usually longer than hooks of 1st and 3rd pairs with a less tapered guard and deeply rounded blade.


Introduction
As natural ecological systems on the earth continue to be rapidly obliterated by human activities it is imperative for scientists with knowledge of field biology to report in the scientific literature the results of field-based surveys based on specimens that were collected and deposited in recognized museums, thus establishing a record of the existence of species before they are completely annihilated (Brooks et al., 2014;Ceballos et al., 2017). Following, we provide descriptions of two new species of cestodes of the family Hymenolepididae recovered from pocket gophers (Rodentia: Geomyidae) collected from relatively high-altitude habitats in both Mexico and Costa Rica of the southern Nearctic and the northern Neotropical regions, respectively. To enable a more complete understanding of the hymenolepidid cestode fauna of pocket gophers, we start this paper by providing a basic introduction to these mammals.
Pocket gophers of the family Geomyidae Bonaparte, 1845 are subterranean rodents that have an extensive geographic and ecological range in the Nearctic and northern Neotropical regions with species representing several genera occupying suitable habitat in mostly the western and far southeastern North America, south through central America into the northern part of South America (Alberico 1990;Hall 1981;Solari 2013).
Extant species of Thomomys are known only from the western part of the Nearctic but fossils that can be as-

Species of Hymenolepis Geographic locality References
Thomomys bottae (Eydoux and Gervais) H. citelli (McLeod, 1933) California Voge, 1955 Hymenolepis sp. (Weinland, 1858) California Voge, 1955 Thomomys bulbivorus (Richardson) H. tualatinensis Gardner, 1985 Willamette Valley, Oregon Gardner, 1985 Thomomys talpoides (Richardson) H. diminuta (Rudolphi, 1819) Eastern Washington State Rankin, 1945 H. citelli Utah Frandsen and Grundmann, 1961 Thomomys umbrinus (Richardson) H. citelli Utah Frandsen and Grundmann, 1961 Geomys bursarius (Shaw) H. diminuta Oklahoma Burnham, 1953 H. weldensis Gardner and Schmidt, 1988 Eastern Colorado Gardner and Schmidt, 1988 H. geomydis Gardner and Schmidt, 1988 Eastern Colorado Gardner and Schmidt, 1988 H. weldensis Illinois/Indiana Haukisalmi et al., 2010 Hymenolepis sp. Texas English, 1932 Geomys Species of the family Hymenolepididae Perrier, 1897 have a cosmopolitan distribution, sometimes occurring in high prevalence and relatively great numerical densities in the gastrointestinal tracts of birds and mammals . Spasskii (1954) was the first author to exclude the hymenolepidids with armed scolexes from the rest of the members of the family that have no armed rostellum. However, the complete life-histories of most species in the family are, as yet, unknown, but of those for which we have data, evidence shows that most life-cycles of cestodes in the Hymenolepididae are complex, and depending on the species, include a bird or mammal as the definitive or final-host, and some species of arthropod as the secondary or intermediate host (Gardner & Schmidt 1988).
This paper reports two new species of cestodes that can be allocated to the family Hymenolepididae. Both were discovered during focussed surveys of pocket gophers in Mexico and Costa Rica. These new species may seem insignificant in the scheme of modern humanity, but the knowledge of their existence in rodents at a specific place and time provides a snapshot view of the ecological complexity that occurred there at that specific moment in time thus providing details about the local environment that would otherwise remain hidden (Manter, 1966;Brooks & McLennan, 1993;Gardner & Campbell, 1992). Subsequent work defining the phylogenetic relationships among these species will be important to enable us to understand the origin of these species relative to their host mammals; this information is essential to both implement and conduct studies based on the DAMA protocol (Brooks et al., 2014) which we fully support.

Materials and methods
Specimens used in the following description of a new genus and species of hymenolepidid were collected in 1990 from agricultural fields and pasture-land at the northeastern edge of the village/city of Potrero Cerrado in the province of Cartago in Costa Rica, elevation 2,140 m (Bonino & Hilje, 1992). While pocket gophers identified as Heterogeomys heterodus (Peters, 1865) were collected and examined for cestodes, no information is available relative to other parasites that may have occurred in or on these same gophers. All cestodes recovered were preserved and stored in 70% ethanol and sent to SLG by Robert M. Timm, University of Kansas. Specimens of H. heterodus collected during the survey were not deposited in a museum in Costa Rica nor anywhere else that we could find (R.M. Timm, pers comm, 1/11/2020).
Material used for the description of the new species of Hymenolepis from Cratogeomys planiceps (Merriam 1895) was collected in 1998 during field surveys led by Mark S. Hafner, Curator Emeritus, Museum of Natural Sciences, Louisiana State University, Baton Rouge, LA. Individuals of C. planiceps were collected from an area consisting of agricultural fields and mixed pine forest near the Parque Nacional Nevado de Toluca, México (Hafner et al. 2004). During this work, one individual of C. planiceps was fortuitously discovered to harbor several tapeworms. The cestodes were preserved directly in 95% ethanol without pre-processing and sent to SLG. The individual pocket gopher from which the cestodes were recovered was deposited in the mammal collection of the LSU museum of Natural Sciences (LSUMZ36120).
In the laboratory, specimens were stained with Semichon's acetic carmine, dehydrated in ethanol, cleared in terpineol and xylene, and mounted permanently on slides in Canada balsam. Specimens were studied using a Zeiss Axiophot TM microscope using both bright-field and Normarsky illumination. Images were prepared using software from Zeiss [AxioVision TM (V4.6.3.0)] and Photoshop CS5 TM . Line drawings were prepared directly from images using "layers" in Adobe Photoshop and a Wacom-Intuos TM tablet and stylus.
Multivariate canonical discriminant (CANDISC), stepwise discriminant (STEP), and principal component analyses (PCA) were conducted with SAS ® software, version 9.4 using 17 quantitative characters taken from six different species of Hymenolepis spp. and Hobergia irazuensis n. gen., n. sp. (Tables 1 & 2). Measurement data from original archival computer files maintained by the Manter Laboratory, for the species H. diminuta (Rudolphi, 1819), H. geomydis Gardner & Schmidt, 1988, H. weldensis Gardner & Schmidt, 1988, H. tualatinensis Gardner, 1985, H. weldensis Gardner & Schmidt, 1988, and H. robertrauschi Gardner et al., 2014 were taken from data originally archived in the HWML from the combined data set of . All measurements of cestodes collected from the pocket gophers C. planiceps and H. heterodus were taken from individual specimens deposited in the Manter Laboratory (HWML No. 139035-139054). An a-priori level of significance of p < 0.05 was set for all statistical analyses. Any deviations from normality in the mensural data were estimated via calculations of skewness and kurtosis using SAS and Microsoft Excel TM . Variables with distributions not conforming to statistical   Gardner (1985); * measurements were taken in present study. **(Total hook length x guard width).
normality were log transformed (log 10 ) and reassessed for normality; any characters that deviated from normality after transformation were not used in the analyses. Log-transformed data were used for all subsequent analyses. In the following, six species of both Hymenolepis and Hobergia n. gen. from Rodentia were included in a canonical variates analysis using 17 quantitative-mensural characters from 41 individual cestodes (see : Table 3 and Figs. 10 & 11). To examine the data-set for well-defined groups the data were first analyzed with a PCA and subsequently analyzed using CANDISC. Five of the six Hymenolepis species analyzed are found exclusively in the Americas; however, H. diminuta as it is currently understood as a species, is cosmopolitan with a global distribution, probably made so via synanthropic hosts which are usually species of the genus Rattus Fischer 1803, but many other species of mammals have been reported as definitive or final hosts for this tapeworm (Burt, 1980). A phylogenetic analysis was conducted using a complex suite of morphological characters, the results of which are being published elsewhere (Gardner & Racz, in review).

TABLE 3.
List of characters with loadings on canonical axes and variation in canonical structure. CAN I, with more than 50% of the variation shown in the analysis is influenced most by the seminal receptacle length and external seminal vesicle length and width; CAN II which contributes about 25% to the total variation in the analysis shows number of proglottids and length of strobila to be most important in separating species.

Results
For the following descriptions, all measurements are given in micrometers unless otherwise specified. Character number 3 refers to number of proglottids. Number of individuals examined is indicated by (N) and numbers in parentheses are mean ± standard deviation (Tables 1 & 2). From complete strobilae, measurements of organs from mature regions were taken from each of the 5 proglottids immediately anterior to those proglottids in which eggs begin to appear in the uterus.

Class Cestoda van Beneden, 1849
Order Cyclophyllidea van Beneden, 1850 Family Hymenolepididae Perrier, 1897 Subfamily Hymenolepidinae Perrier, 1896 Hobergia n. gen.  LSIDurn:lsid:zoobank.org:act:439BC5C8-B0AE-4108-94ED-044B34E1DB9D Type and only species: Hobergia irazuensis n. gen., n. sp. Diagnosis: Hymenolepididae, Hymenolepidinae. Strobila elongate, widest at level just anterior to terminal gravid proglottids. Strobila attenuated and narrowest in neck region, posteriad to scolex. Scolex with four fully developed and separate suckers (Fig. 1). Each sucker with foveola and associated structures. Foveolae completely contain suckers when suckers are retracted (Fig. 2). Apical organ, piriform (Fig. 1). Anterior most part of osmoregulatory canals not penetrating apical organ sac. Transverse tubes connect ventral osmoregulatory canals. Genital ducts pass dorsal to osmoregulatory canals. Genital pores dextral, marginal, and unilateral. Cirrus sac, internal seminal vesicle, and external seminal vesicle dorsal to seminal receptacle, ovary, vitelline gland, and Mehlis' gland. Vitelline and Mehlis' glands posterior and slightly ventral to divided ovary. Two laterally extended lobes of ovary, connected by narrow isthmus, clearly lie on each side of vitelline gland. Gravid proglottids with transverse saccular uterus. Terminology of egg morphology follows Ubelaker (1980). Eggs (Fig. 6) subspherical, embryophore larvae with three pairs of hooks, including: 1 st pair dimorphic consisting of 1 small and 1 large hook, 2 nd (middle pair) monomorphic delicate, 3 rd pair dimorphic consisting of 1 small and 1 large hook. Large embryo hooks have a wide and thick guard compared to the small embryo hooks of both the middle pair and the paired small-hooks of 1 st and 3 rd pairs. Middle pair of embryo hooks identical, with falcate blade having shallow curve and with most delicate and narrow guard of all three embryo hook types (Fig. 6).
Etymology: The new genus is named in honor of Dr. Eric P. Hoberg who was the last curator of the United States National Parasite Collection. We honor Eric's life-long dedication and acknowledge his tireless studies of the taxonomy, systematics, phylogenetics, historical ecology, and biodiversity of parasites of planet earth.
Etymology: Hobergia irazuensis n. sp. was named for the Volcán Irazú near the type locality, Costa Rica, northern Neotropical region.
Remarks: Hobergia irazuensis n. gen., n. sp. exhibits the characteristics of Hymenolepis as defined by Schmidt (1986) but refined and complemented by Makarikov & Tkach (2013). The following comparisons are restricted to members of the genus Hymenolepis known to occur in mammals of the Nearctic region, see Gardner (1985) and Gardner & Schmidt (1988).

Comparison of H. irazuensis n. gen., n. sp. with other hymenolepidids found in the Nearctic
Hobergia irazuensis n. gen., n. sp. is readily distinguishable from all other known species of Hymenolepididae in the Nearctic by the presence of sucker foveolae on the scolex. Each of the four suckers on the scolex has a pocketlike foveola in which the sucker can retract. The tissue of the foveola covers each sucker with a thin membrane (Fig. 2) which appears striated and likely involved in foveola structure or function in retraction of the suckers into the foveolae. Additionally, H. irazuensis can be differentiated from species of Hymenolepis s. str. in the Nearctic by the following characters: Ovary extremely bilobed with a central thin isthmus only a few cells in diameter; no other described species of Hymenolepis s. str. has this structure. In addition, the new species has a much longer and wider scolex and wider neck relative to all described species.
Etymology: This tapeworm species was named after the generic name of its type host "cratogeomyos" meaning "of Cratogeomys." Differential Diagnosis: Hymenolepis cratogeomyos n. sp. exhibits characteristics of Hymenolepis as defined by Yamaguti (1959) and Schmidt (1986) but later refined by Makarikov & Tkach (2013). There is no evidence that geomyid rodents have ever occurred in the Palearctic region (Kurtén & Anderson, 1980) therefore we restrict comparison of this species with those of the genus Hymenolepis known to occur in mammals from the Nearctic and Neotropical regions, see Gardner (1985) and Gardner & Schmidt (1988). Hymenolepis cratogeomyos n. sp. can be recognized as distinct from all known species of Hymenolepis from the Nearctic region by possessing a greater width of dorsal osmoregulatory canal, longer seminal receptacle, and an apical organ sac with lightly crenulated margins.

Comparisons of H. cratogeomyos with other hymenolepidids from geomyid rodents
Hymenolepis cratogeomyos differs from H. geomydis in having a greater number of proglottids, longer apical organ, shorter and narrower apical organ sac, shorter neck, smaller vitelline gland, wider ventral osmoregulatory canals, longer and wider external seminal vesicle, smaller width of egg and embryo, anlagen of genitalia appearing earlier, wider guard of first and third pairs of large hooks, more compact ovary, and smooth vitelline gland margins.
Hymenolepis cratogeomyos n. sp. can be separated from H. weldensis by the following characters: wider strobila, a greater number of proglottids, longer apical organ, shorter and narrower apical organ sac, shorter neck, shorter cirrus sac, longer testes, longer and wider external seminal vesicle, expanded ovary, deeper genital atrium, narrower embryo, and earlier anlagen of genitalia. Hymenolepis cratogeomyos also differs from H. weldensis in the shape and armature pattern of the cirrus, the cirrus of H. cratogeomyos is partially clavate with well-defined gridded rows of minute hooks. Hymenolepis cratogeomyos differs from H. tualatinensis in being larger in all respects except that H. cratogeomyos has eggs possessing embryophores that are smaller and the anlagen appears earlier in the strobila. In addition, H. cratogeomyos differs from H. tualatinensis in having an ovary that is compact, fan-shaped, and with multiple lobes, genital pores, a cirrus that is clavate and with a different pattern of spines, and eggs with hooks that are much more robust than those in H. tualatinensis.
Hymenolepis cratogeomyos can be readily distinguished from H. irazuensis by the more compact ovary (not extremely bilobed as in H. cratogeomyos) and the fact that the scolex has no sucker pockets. Hymenolepis cratogeo-myos can be readily distinguished from H. irazuensis in having a longer and wider strobila, greater number of proglottids, shorter and narrower apical organ sac, narrower neck, wider seminal receptacle, shorter and wider ovary, smaller vitelline gland, shorter and wider external seminal vesicle, deeper genital atrium, wider ventral excretory canal, and longer and wider eggs and embryo. The embryo hooks of H. cratogeomyos differ from the hooks of H. irazuensis by the following characters: a longer handle, blade, and total length and a narrower guard of the big and small hooks of the first and third pairs, and greater total length of the middle embryo hooks. Additionally, H. cratogeomyos has an ovary that is multilobed with deep small lobes and not extremely bilobed, cirrus sac that partially overlaps the ventral excretory canal, and a smooth-edged vitelline gland.

Comparisons of H. cratogeomyos with Hymenolepis species from Sciurid, Cricetid, and Murid Rodents in the Nearctic.
Hymenolepis cratogeomyos can be separated from H. robertrauschi in having a longer and wider strobila, greater number of proglottids, longer apical organ, shorter cirrus sac, longer and wider external seminal vesicle, wider ventral canals, narrower internal seminal vesicle, narrower embryo, and the anlagen of the genitalia appears earlier in the strobila. In addition, H. cratogeomyos differs from H. robertrauschi by the following characters: a piriform cirrus sac, cirrus armature arrangement of well-defined rows, and cirrus sac that crosses osmoregulatory canals to the mid line of the ventral canal, this in contrast to the cirrus sac of H. robertrauschi that does not touch or cross the osmoregulatory canals.
Hymenolepis cratogeomyos differs from H. pitymi by the following characters: longer and wider strobila, greater number of proglottids, shorter apical organ, wider apical organ sac, longer and wider neck, longer and wider cirrus sac, longer and wider external seminal vesicle, longer and wider internal seminal vesicle, wider seminal receptacle, longer and wider ovary, longer vitelline gland, deeper genital atrium, wider ventral excretory canals, longer and wider eggs, wider embryos, and greater total length of middle embryo hooks and a cirrus armature arrangement of well-defined gridded rows.
Hymenolepis cratogeomyos can be recognized as distinct from H. folkertsi in having a wider strobila, greater number of proglottids, shorter apical organ, shorter and narrower apical organ sac, deeper genital atrium, wider seminal receptacle, longer and wider external seminal vesicle, longer and wider testes, and wider ventral canals. Hymenolepis cratogeomyos can be distinguished from H. folkertsi in having the following characters: piriform cirrus sac that usually overlaps the ventral excretory canal, clavate cirrus, and a much more reduced AO relative to that of H. folkertsi.
Hymenolepis cratogeomyos is readily distinguishable from H. diminuta by the following characters: wider strobila, more great number of proglottids, longer apical organ, shorter and narrower apical organ sac, longer neck, shorter cirrus sac, wider external seminal vesicle, shorter internal seminal vesicle, deeper genital atrium, wider ventral excretory canals, narrower embryo, narrower guard of middle embryo hooks, and earlier anlagen of genitalia. Hymenolepis cratogeomyos can be recognized as distinct from H. diminuta by the following characters: non-alternating genital pores, a cirrus sac that usually overlaps the ventral excretory canal, and cirrus spines formed in evenly spaced rows and columns.
Generally, the characters that serve to distinguish H. diminuta from other species also suffice to distinguish H. citelli from other species as the adult characters of H. diminuta and H. citelli appear indistinguishable (Gardner & Schmidt 1988). Hymenolepis cratogeomyos can be recognized as distinct from H. citelli by the following characters: wider strobila, shorter apical organ, shorter and narrower apical organ sac, longer and wider neck, longer and wider internal seminal vesicle, longer external seminal vesicle, longer testes, wider seminal receptacle, wider ventral excretory canal, wider cirrus sac, piriform cirrus sac, and a genital pore that is non-alternating. Note: It is the opinion of the authors that new specimens from the type locality of H. citelli should be collected to confirm its validity.
Hymenolepis cratogeomyos can be recognized as distinct from H. scalopi Schultz, 1939 described from Scalopus aquaticus Linnaeus, 1758 collected from the vicinity of Stillwater, Oklahoma by the following characters (see Table 2): wider strobila, greater number of proglottids, longer apical organ, shorter and narrower apical organ sac, earlier anlagen of genitalia, longer and wider external seminal vesicle, longer testes, wider seminal receptacle, shorter ovary, shorter vitelline gland, wider and shorter neck, deeper genital atrium, and a larger ventral excretory canal. In addition, H. cratogeomyos can be separated from H. scalopi in having a piriform cirrus sac that extends further than the ventral excretory canal, and a larger ovary that is expanded laterally. Note: It is interesting that this species has never been reported after its initial description. At this time we have been unable to locate the voucher specimens of the type host H. scalopi so it remains an enigma as to whether this cestode was actually recovered from a mole collected from near Stillwater, OK.

Prevalence of hymenolepidids in Geomyidae of Costa Rica and México
During the field work by Bonino in Costa Rica (1989Rica ( -1990, 127 individuals of H. heterodus, were collected and examined for helminths. Hobergia irazuensis n. gen., n. sp. was found in 1.6% of all specimens examined; all infected individual pocket gophers were found at a single collection locality, occurring in 5.3% of those individuals of H. heterodus examined at the locality Potrero Cerrado. Relative to Hymenolepis cratogeomyos n. sp., one individual of C. planiceps was incidentally found infected with cestodes (Hafner et al. 2004).

Statistical Analyses
To examine the extent of morphological divergence among all species of Hymenolepis s. str. in the Nearctic and Northern Neotropical regions a PCA and CANDISC were performed. The PCA ordination (Fig. 10) shows relatively good separation of species using the first two components. The CANDISC ordination (discriminant analysis works on previously defined groups and maximizes the differences among the groups) shows distinct separation among all species included in this analysis (Fig. 11). The CANDISC analysis shows that all multivariate means or centroids are significantly different from each of the seven species of hymenolepidids evaluated (F= 11.34, df =102,109.62, p < 0.0001). Characters most important for discriminating among species in this study were determined by stepwise discriminant analysis and include: number of proglottids, cirrus sac length, maximum strobila length, ovary width, seminal receptacle length, vitelline gland width, cirrus sac width, and maximum strobila width. Measurements of scolexes, eggs, and embryophores were not included in the multivariate analysis due to the low number of these characters available for comparative species.

Discussion
The discovery of these two new species of cestodes adds critical new information to our knowledge of the known species of rodent-specific Hymenolepididae in both the Mesa Central of Mexico and the volcanic region of Costa Rica. The record of Hobergia irazuensis from H. heterodus in the highlands of Costa Rica is the first report of a hymenolepidid from geomyid rodents in the northern neotropics; however, we expect that additional sampling of geomyids throughout their ranges will reveal hidden parasite diversity that has been previously ignored by biodiversitists.
Across the Nearctic and northern Neotropical regions, six species of the genus Hymenolepis are now known to occur in species from three of the six genera of Geomyidae. Hymenolepis citelli and H. weldensis have been reported from more than one species of geomyid rodent (Gardner & Schmidt 1988) and both H. diminuta (Table 1) and H. weldensis have been transferred experimentally to, and appear to thrive in, experimentally infected species of Geomys, Thomomys, and Cratogeomys (see Gardner & Schmidt 1988). The fact that Hymenolepis weldensis and H. diminuta were transferred experimentally from geomyids to beetles of the family Tenebrioniidae (Tenebrio molitor L.) and then to gophers, indicates that any host specificity of these species of tapeworms to geomyids does not manifest or show physiological or phylogenetic host specificity, but instead is most likely a result of ecological host specificity (separation of host and parasite based on ecology or geographic distances). Based on the potential for ecological fitting (see reviews in Brooks et al., 2014 andWeaver et al., 2016) of Hymenolepis spp. among the diverse and widely distributed species of Geomyidae and the requirements of the complex life cycles of these cestodes combined with the broad geographic distribution of the geomyids, it is clear that additional biodiversity surveys throughout the Nearctic and Neotropical regions are required to understand the dynamic evolutionary and ecological history of the species of Hymenolepididae in geomyid rodents.  Parasites with complex life-cycles, such as cestodes that occur in species of Geomyidae, are important indicators of biodiversity that is many times hidden with only parts of the fauna of a region or locality functioning in host-parasite systems (Manter 1966;Brooks & McLennan 1993). If a parasite with a complex life-cycle is shown to be present in one or several host species in an area, it is immediately clear that all essential ecological requirements for both definitive and intermediate hosts are also present in the ecosystem (Gardner & Campbell 1992;Hoberg 1997). Thus, discovery of parasites with complex life-cycles in this case, mammals, but in fact any other vertebrates in any geographic locality serves to immediately expose to examination previously hidden and perhaps unknown and undiscovered biodiversity. Finally, putting the species associated with these discoveries into a phylogenetic context adds historical depth to the discovery of species (Gardner & Campbell 1992;Brooks et al. 2014;Racz & Gardner submitted).
With the inclusion of the two new hymenolepidids described herein, we consider the genus Hymenolepis to contain 20 species with one new species allocated to a new genus, defined above.