﻿Helminth and protozoan parasites of subterranean rodents (Chordata, Mammalia, Rodentia) of the world

﻿Abstract Published studies and ten new unpublished records included herein reveal that approximately 174 species of endoparasites (helminths and protozoans) are known from 65 of 163 species of rodents that occupy the subterranean ecotope globally. Of those, 94 endoparasite species were originally described from these rodents. A total of 282 host-parasite associations are summarized from four major zoogeographic regions including Ethiopian, Palearctic/Oriental, Nearctic, and Neotropical. Thirty-four parasite records from the literature have been identified to only the level of the genus. In this summary, ten new records have been added, and the most current taxonomic status of each parasite species is noted. Interestingly, there are no data on endoparasites from more than 68% of described subterranean rodents, which indicates that discovery and documentation are at an early stage and must continue.


Introduction
Subterranean rodents are animals adapted to live underground with minimal dependency on surface resources. They exhibit numerous adaptations to maintain their life activities in this niche including almost no externally visible neck, small eyes and ears, short legs, and very loose skin with soft fur that enables them to turn in their burrows with ease (Maser et al. 1981;Lacey et al. 2000). Conditions within the burrow systems are characterized by complete darkness, constant temperatures, relative humidity of 100% with low levels of air circulation, elevated carbon dioxide levels, and usually closed tunnels.
In contrast to mammals that live on the surface of the soil, subterranean rodents are completely acclimated to live in complex burrow systems below the surface. These animals have the capability to dig burrow systems through many types of friable soils (Lessa et al. 2008). The underground habitat has been invaded by rodents utilizing specialized digging methods in all zoogeographic regions of the world. However, rodents with the ability to dig tunnels underground by utilizing strong digging limbs as well as other morphological and physiological traits occur in all zoogeographic regions except Australia and Antarctica and adaptations by non-phylogenetically related groups to a subterranean existence are considered a product of convergent evolution (Losos 2011). Approximately 40% of the 6,500 mammal species of the world are rodents. Even though only 6.5% of all rodent species occupy the subterranean ecotope, these mammals play an essential part of the ecology in the areas in which they live, functioning as biological plows, cycling the earth, changing the landscape, promoting plant growth and ecological succession, and playing a critical role in cycling carbon and other nutrients through the soil. In the order Rodentia, a total of 163 extant subterranean species across 23 genera, within seven families, has been recognized with distributions throughout all continents except Antarctica and Australia (see Table 1) (Van Daele et al. 2007;Wilson et al. 2016Wilson et al. , 2017. Based on macroevolutionary patterns derived from the study of the fossil record, subterranean rodent species diversity has appeared to have oscillated since early Oligocene time [ca. 36 million years ago, (mya)]. The Geomyidae Bonaparte, 1845 and the Bathyergidae Waterhouse, 1841 have the greatest diversity among all subterranean rodent families relative to the number of genera found throughout evolutionary time and identified thus far as fossil taxa (Cook et al. 2000). Fluctuation cycles in diversification, known as taxon pulses (Erwin 1985) appear to have been driven by local, regional, and global climate oscillations, and explained by the Stockholm Paradigm, which seeks to provide an understanding of the evolution of host-parasite/pathogen systems via the evolutionary process of species diversification following mass extinctions (Brooks et al. 2019).

Nearctic subterranean rodents
Species of the family Geomyidae are endemic to the Nearctic and northern Neotropics and are known collectively as pocket gophers due to presence of fur-lined cheek pouches in all species. They are a monophyletic group of subterranean rodents that share common ancestry with rodents of the family Heteromyidae (Wilson et al. 2016). Pocket gophers inhabit a wide geographic range, extending from a northernmost limit in southwest and south-central Canada through the central and western United States, southeast into central Florida, and south into Mexico and through Central America into Panama and near the Rio Atrato in northern Colombia (Hall 1981;Alberico 1990;Solari et al. 2013). As in most subterranean rodents, pocket gophers are fusiform in shape, having a naked and sensitive tail (they can run backwards as fast as they can forwards, using their tail as a rear-guide sensor (Gardner, pers. obs.). They have small pinnae, loose skin, and their fur-lined cheek pouches are used only for food transport (Howard and Childs 1959;Maser et al. 1981;Hafner 1982;Honeycutt and Williams 1982;Hafner et al. 1994). The family consists of seven extant genera and 41 species (Wilson et al. 2016).
The genus Thomomys Wied-Niewied, 1839, has 12 species and many subspecies, making this genus the most speciose of the family Geomyidae (see Patton 2005).

Palearctic subterranean rodents
Thirty-two species of subterranean rodents of seven genera in two families, including Cricetidae Fischer, 1817, and Spalacidae Gray, 1821, occur in the Palearctic region. Those include Prometheomys Satunin, 1901, andEllobius Fischer, 1814, in the family Cricetidae, which includes the subfamily Arvicolinae Gray, 1821. The genera Myospalax Laxmann, 1769, Eospalax Allen, 1938, Rhizomys Gray, 1831, Cannomys Thomas, 1915, Spalax Guldenstaedt, 1770, and Nannospalax (Nordmann, 1840 are in the family Spalacidae which includes the subfamilies Myospalacinae Lilljeborg, 1866, Rhizomyinae Winge, 1887, and Spalacinae Gray, 1821. Among all subterranean forms of the Rodentia, those occurring in the Palearctic region have the most extensive geographic distribution. Based on fossil evidence, the first known subterranean species of rodents appeared in the early Pliocene of Asia (Repenning 1984;Repenning et al. 1990 (Reig et al. 1990;Gardner et al. 2014). The fossil record indicates that species that can be allocated to the family Ctenomyidae originated ca. 10 mya (Cook et al. 2000), with rapid diversification in the genus Ctenomys commencing at ca. 3 mya (Parada et al. 2011). Interestingly, the single subterranean species in the Octodontidae which are the sister taxon of the Ctenomyidae includes the monotypic Spalacopus cyanus (Molina, 1782) and these occur only in central Chile.

Endoparasites
Our analysis shows that endoparasites have been found and reported from fewer than 40% of known species of subterranean rodents world-wide. There are several factors that could potentially explain this lack of reported data as researchers face several challenges when trapping subterranean rodents; without prior training, just finding and then determining active subterranean mammal burrow mounds is difficult. There could be thousands of burrow mounds, but researchers need acute field expertise to identify freshly dug burrows to capture these animals. Moreover, setting subterranean rodent traps is labor intensive and time-consuming, demanding lots of patience, physical strength, and luck. Another problem is that sampling of species of subterranean rodents has not been systematically carried out and most collecting was done over time that was rather scattered and sporadic, and very few collections included parasites in their investigations. Many previous studies have failed to record comprehensive data during their collections of mammals and other vertebrates, discarding the internal organs of collected mammals without further examination. This practice resulted in significant gaps in parasite data with black holes regarding their faunas of both ecto-and endoparasites. Parasites discovered in research projects contain vital information about themselves and their host life history, consisting of information that we cannot ignore. The work presented here represents a synthesis of all available literature on the endoparasites of subterranean rodents of the world, as such, some references and works may have been missed, but we hope that this list provides a starting point for other researchers interested in this area of study.

Materials and methods
The current checklist was created by accumulating all published references arranged in a chronologically ordered tabular form representing globally each continent. The taxonomic status of each host and parasite species are up to date and represent the most current classifications. Most of the early literature was located in the reprint library of the H.W. Manter Laboratory of Parasitology in the University of Nebraska State Museum. Some of the literature was obtained from the Digital Commons at University of Nebraska-Lincoln Libraries while several rare international references were obtained through interlibrary loan. For new records presented herein, some samples were collected during the field Parasitology class in western Nebraska and others were included from field work by S.L. Gardner in the 1980's the 1990's and earlier.
Except for a few instances that we detail in the results, we used the original taxonomic names of both the hosts and parasites as published in the original literature. Throughout this paper, we used the zoogeographic terminology first established by Wallace (1876) (Rueda et al. 2013).
Several years later, De Graaff (1981) reported Inermicapsifer madagascariensis (Davaine, 1870) from the Common mole-rat, Cryptomys hottentotus (Lesson, 1826) (Bathyergidae: Hystricomorpha), collected from Shingwedzi, South Africa.  Scharff et al. (1997) reported Inermicapsifer madagascariensis from the small intestine, and Protospirura muricola (Gedoelst, 1916) from the colon of Fukomys kafuensis (Burda et al., 1999) collected from Itezhi-Tezhi, Zambia. They also found an unidentified species of Calodium Moravec, 1982 (syn. Capillaria Zeder, 1800) (eggs only), I. madagascariensis, and an unknown Raillietina Fuhrman, 1920, from the small intestine, and P. muricola from the abdominal cavity of Fukomys mechowii (Peters, 1881) collected from Ndole, Zambia. The discovery of P. muricola in the abdominal cavity was probably a result of these nematodes moving from the stomach during or after the necropsy event of the individual F. mechowii mentioned. Koudela et al. (2000) described Eimeria burdai, as a new species of coccidian from the subterranean African silvery mole-rat, Heliophobius argenteocinereus Peters, 1846, collected from Lubalashi Province, central Zambia. Baruš et al. (2003) studied the relative concentration of heavy metals in helminth parasites; several Silvery mole-rats, H. argenteocinereus, were necropsied for their internal parasite tissues collected from the Blantyre-Limbe region of Malawi, southeastern Africa. As a result, two species of helminths were found, including Inermicapsifer arvicanthidis (Kofend, 1917) and Protospirura muricola, and these specimens were later examined for four heavy metal elements (cadmium, copper, lead, and zinc), and compared against the liver and muscle tissues of their hosts. The same species of parasites from these same hosts were reported by Tenora et al. (2003).

Palearctic subterranean rodent endoparasites
See graphical summary in Fig. 2 and endoparasite list in Table 3.
Interestingly, even though helminthology began in Europe (the western Palearctic) in the late 1800's with the work of Leuckart, it was not until the 1920's when Schulz (1927) described the first two species of helminth parasites from two species of subterranean rodents from the Palearctic region. First, Physocephalus ellobii Schulz, 1927 was found from the stomach of Ellobius tancrei Blasius, 1884 collected from Kotlyrevsky, the northern Caucasus region of Russia. Second, Gongylonema longispiculum spalacis Schulz, 1927 was described as the first subspecies found under the mucous membrane of the stomach of Spalax microphthalmus Güldenstädt, 1770 collected from the village Kurichya Kosa near the Don River region north of the coast of the Sea of Azov, Russia. Soon after, Marcu (1930) described Mammalakis spalacis Marcu, 1930 also obtained from S. microphthalmus collected from Romania.
Soon after, Makarikov and Tkach (2013) Zhao et al. (2014) identified Versteria (syn. Taenia) mustelae (Gmelin, 1790) using DNA sequencing of larval cysts found in the Plateau zokor, Eospalax baileyi collected from Datong County, east of Qinghai province, China. In this study, no data were provided on number of individuals infected. Afonso et al. (2015) reported Echinococcus multilocularis from the livers of Eastern mole voles, Ellobius tancrei which acts as the intermediate host for this cestode, collected from Sary Mogol, Alay valley, Kyrgyzstan. The authors also noted that the definitive hosts were local domestic dogs, whose feces were examined for E. multilocularis. The parasite samples from the dogs were genetically identical to those found in the intermediate host.
In 2017, a flurry of activity resulted from workers in the field. Vlasenko and Krivopalov (2017)

Endoparasites of Nearctic and northern Neotropical subterranean rodents
See graphical summary in Fig. 3 and endoparasite list Table 4.
Leidy in (1857), at a meeting of the Academy of Natural Sciences of Philadelphia, displayed some warbles taken from an evidently incapacitated pocket gopher by the side of the road, identified as T. borealis [probably a synonym of T. talpoides] near the Bridger's pass summit of the Rocky Mountains. This record represents the first known report of an endoparasite from a member of the rodent family Geomyidae. Soon after the groundbreaking work by Leidy, Charles Wardell Stiles (1895) reported the first helminth parasite from a geomyid when he described Pseudocittotaenia praecoquis (Stiles, 1895) from Geomys bursarius (Shaw, 1800) collected near Ames, Iowa (Stiles, 1897). Hall (1912) reported on the parasite fauna of Colorado and recorded several nematodes and some unidentified cestodes from Thomomys fossor J.A. Allen (probably a syn. of T. talpoides). Soon after, Herman Douthitt (1915) described four new species of anoplocephalid cestodes from pocket gophers collected from the central United States. Anoplocephaloides variabilis (Douthitt, 1915), A. infrequens (Douthitt, 1915), and Andrya macrocephala Douthitt, 1915 were all described from specimens taken from G. bursarius collected from Illinois, Minnesota, and North Dakota. Monoecocestus anoplocephaloides (Douthitt, 1915) was described from some specimens taken from Geomys breviceps Baird collected near Norman, Oklahoma. Douthitt (1915) also reported one unidentified species of Oöchoristica Luhe, 1898, and one immature form of Cittotaenia, now known as Pseudocittotaenia, Tenora, 1976from G. bursarius. Douthitt (1915 also reported numerous individuals of eight different species of Hymenolepis from two species of pocket gophers including: G. bursarius collected in Illinois, Figure 3. Percentage taxon composition pie diagram of the higher classification of endoparasite diversity occurring in Nearctic subterranean rodents (Family Geomyidae) derived from literature records published from 1857 through 2020. Among these endoparasites, the Nemata represent 46% of the species found followed by Cestoda (41%), Protozoa (11%), and Acanthocephala at just 2%.
Wisconsin, Minnesota, North Dakota, and Manitoba, Canada; G. breviceps collected in Oklahoma and Texas; and Geomys personatus True, collected in Texas. Hall (1916) described the following nematodes from Thomomys fossor J. A. Allen [syn. T. talpoides (Richardson, 1828)]: Trichuris fossor Hall, 1916, from specimens collected near both Crested Butte and Livermore, Colorado and Vexillata vexillata (Hall, 1916) from gophers collected from mountain meadows near Livermore, Colorado. These nematodes were described from the same material that Hall (1912) had previously studied. Additionally, the nematode Protospirura ascaroidea Hall, 1916 was described from specimens recovered from the stomachs of Geomys bursarius collected near Norman, Oklahoma by Herman Douthitt and sent to MC Hall for study. Skidmore (1929) described a species of Coccidia named Eimeria geomydis Skidmore, 1929 from the intestinal tract of Geomys bursarius Shaw, collected near Lincoln, Nebraska while Dikmans (1932) reported Capillaria (syn. Calodium) hepaticum (Bancroft, 1893) as a parasite of Thomomys fossor (syn. T. talpoides) collected in the Medicine Bow Mountains of Wyoming. In that same year, English (1932) examined 161 specimens of Geomys bursarius collected in Brazos County, Texas and found 23 infected with the stomach nematode Protospirura ascaroidea Hall, 1916, and eight infected with an unknown species of Hymenolepis. Hubbell and Goff (1939) reported Mastophorus muris ascaroides (Gmelin, 1790) to occur commonly in the stomach of Geomys sp. (most likely G. pinetis) collected near Leesburg, Lake County, Florida.
The next year, Voge (1956), in a list of the nematode parasites of California mammals, reported Trichuris fossor Hall, 1916 as a parasite of T. bottae and in the same year, Lubinsky (1956) reported Calodium (syn. Capillaria) hepaticum from T. talpoides in Alberta, Canada. Soon after, continuing his work on small mammals, Lubinsky (1957) in a list of the helminth parasites of rodents from Alberta included the following as parasites of Thomomys talpoides: Versteria (syn. Taenia) mustelae (larvae) from the mesenteries, lungs, liver, and kidneys of gophers collected in northern and middle Alberta: Anoplocephaloides variabilis (Douthitt, 1915) recovered from the colon (which is a doubtful location for a cestode) from six localities in middle and southern Alberta; Calodium (syn. Capillaria) hepaticum from the livers of gophers collected from central and southern Alberta; Trichuris fossor from the cecum of gophers collected from central Alberta; Protospirura ascaroidea Hall, 1916 from the stomachs of gophers from middle Alberta; Litomosoides carinii (Travassos, 1919) from the coelom of pocket gophers from middle and southern Alberta. In the same year, Levine, et al. (1957) described Eimeria thomomysis from specimens of T. bottae collected in the Grand Canyon of Arizona. Howard and Childs (1959) during a study of the ecology of Thomomys monticola reported Hymenolepis horrida (von Linstow, 1901) to occur commonly in adult pocket gophers. They stated, "Most of the adults had several tapeworms (Hymenolepis horrida), and one animal had 108 immature tapeworms with short strobila. None of the five juvenile gophers examined had tapeworms." Based on recent work by Dursahinhan et al. (2022), it appears now that the species identified as H. horrida may be referred to the genus Arostrilepis. Frandsen and Grundmann (1960) discussed the geographic distribution of Trichuris fossor Hall, 1916 andRansomus rodentorum Hall, 1916 from Thomomys talpoides and T. umbrinus in the Lake Bonneville basin of Utah. They speculated that the distribution of these two species of nematodes in Thomomys sp. in this area supports the contention that competition occurred between the two species of pocket gophers resulting in the present-day distribution patterns of the pocket gophers and their respective helminths. Rausch (1961) reported Calodium (syn. Capillaria) hepaticum from Thomomys talpoides tenellus Goldman from near Moran, Wyoming, collected in June of 1948 and Frandsen and Grundmann (1961) reported the following helminth parasite species from several subspecies of both Northern pocket gopher, Thomomys talpoides, and the Southern pocket gopher Thomomys umbrinus (Richardson, 1829). These species include Ascaris laevis Leidy, 1856, Hymenolepis citelli, Ransomus rodentorum, and Trichuris fossor. However, Anoplocephaloides infrequens (Douthitt, 1915), A. variabilis (Douthitt, 1915), Pseudocittotaenia praecoquis (Stiles, 1985), Arostrilepis horrida, and Nippostrongylus muris (Yokogawa, 1920) have been reported from T. talpoides. In addition, Paruterina candelabraria (Goeze, 1781) and Moniliformis clarki are only reported from T. umbrinus. Stock (1962) reported three males and one female of the nematode Ransomus rodentorum from the cecae of two specimens of Thomomys talpoides fossor, collected at the junction of Dry Gulch and the Gunnison River, Colorado, at ca. 7,400 feet altitude. Rissky (1962) reported Monocercomonoides from the cecum of the Plains pocket gopher, Geomys bursarius, collected from Clay County, South Dakota. Ubelaker and Downhower (1965) in a study of the endo and ectoparasites of Geomys bursarius in Kansas, reported Calodium (syn. Capillaria) hepaticum from the cecum of a single pocket gopher and Andrya macrocephala Douthitt, 1915 and Anoplocephaloides infrequens (Douthitt, 1915) were found to occur in seven and six of the pocket gophers examined, respectively. Lainson (1968), during a parasitological study in El Cayo District British Honduras, a new species of coccidian parasite (Eimeria orthogeomyos) was described from the Giant pocket gopher, Orthogeomys grandis (Thomas, 1893) collected from Baking Pot, El Cayo District, Central America (Lainson, 1968). Tryon and Cunningham (1968) in a study of Thomomys talpoides along an altitudinal transect in the Beartooth Mountains of Wyoming reported Calodium (syn. Capillaria) hepaticum from the livers of 5%, 37%, and 8% of the gophers from the Alpine, the Canadian, and the transition life zones, respectively. Douglas (1969) studied the ecology of the pocket gophers of Mesa Verde, Colorado. He reported Trichuris fossor Hall, 1916 and Cuterebra cf. cyanella (bot fly larvae) from Thomomys bottae aureus Douglas (1969) stated that, "Of the gophers infected with bot fly larvae, the highest prevalence of infection occurred during September, with no gophers carrying larvae during the spring." Douglas (1969) also stated "Specimens of Cestoda currently are being studied and will be reported elsewhere." To our knowledge, no report has ever been published. Todd and Tryon (1970) described Eimeria fitzgeraldi Todd & Tryon, 1970 from Thomomys talpoides collected from the Beartooth Mountains, Park County Wyoming. Oocysts were recovered from the feces of two of ten juvenile males and one of 31 adult females (pocket gophers). Todd et al. (1971) in a study of the endoparasites of the Northern pocket gopher (Thomomys talpoides) from Park County, Wyoming, reported the following species of parasites from a total of 46 specimens of T. talpoides examined: Eimeria thomomysis Levine, Ivens & Kruidenier, 1957 was found to occur in the fecal pellets of 24 of the individual gophers; E. fitzgeraldi Todd & Tryon, 1970 was found in the feces of two gophers; cestode cysticerci of the family Taeniidae were found in the mesenteries near the stomach and cecum of one gopher; fragments of the cestode Catenotaenia linsdalei McIntosh, 1941 were found in the body cavities of two animals (this is a dubious body location record); Anoplocephaloides variabilis (Douthitt, 1915) was present in the small intestines of 18 gophers; A. infrequens (Douthitt, 1915) was recovered from the small intestine of seven gophers; Anoplocephaloides sp. was recovered from the small intestines of 22 gophers R. rodentorum was found in the cecum of 34 gophers, and in the large intestine of one; Vexillata vexillata was recovered from the small intestines of two gophers; Protospirura ascaroidea was found in the stomachs of two animals; Trichuris fossor was found in the ceca of 30 gophers; and Calodium (syn. Capillaria) hepaticum was recovered from the livers of 18 of the gophers examined. Todd and Lepp (1972) redescribed Trichuris fossor from specimens recovered from T. talpoides from Park County, Wyoming. Grundmann et al. (1976), in a paper discussing the mechanisms of parasitic helminth population regulation in rodents, listed the following parasites as occurring in Thomomys talpoides in Utah: Trichuris fossor, Vexillata vexillata, Ascaris laevis Leidy, 1856. Hymenolepis horrida, and T. fossor were reported from T. bottae in the same paper.  in a study of the rodent cestode genera Paranoplocephala Luhe, 1910 and Anoplocephaloides Baer, 1923 examined the type material of Anoplocephaloides infrequens (Douthitt, 1915) from Geomys bursarius collected by Douthitt in Brainerd, Minnesota, and specimens of A. variabilis (Douthitt, 1915) collected by Douthitt in central Illinois from Geomys bursarius. Also studied by  were seven specimens of A. variabilis from Thomomys talpoides collected at Emerson, Manitoba, 10 km north of Prince Albert, Saskatchewan, Canada and from 5 km south of Saskatoon, Saskatchewan, Canada.  stated "I also obtained it (A. variabilis from T. talpoides) in two of 11 of these rodents at Moran, Wyoming, in 1949." Beveridge (1978 in a revision of the genus Pseudocittotaenia Tenora, 1976, listed the synonyms of P. praecoquis (Stiles, 1895) and described P. glandularis Beveridge, 1978 from some specimens taken from Thomomys talpoides in Utah by Frandsen and Grundmann (1961), and from some specimens from T. talpoides in Wyoming. Frandsen and Grundmann (1961) evidently misidentified P. glandularis Beveridge, 1978 and had determined that the specimens that they found in T. talpoides were Pseudocittotaenia praecoquis (Stiles, 1895). The specimens from the Wyoming pocket gophers were from material that Smith (1951) had mistakenly identified and redescribed as P. praecoquis. Beveridge (1978) also listed as synonyms: P. megasacca (Smith, 1951) with P. praecoquis (Stiles, 1895). Also reported by Beveridge (1978) and not reported elsewhere in the literature was Pseudocittotaenia praecoquis from T. talpoides tenellus Goldman, collected by Robert L. Rausch near Moran, Wyoming in June of 1948. Jasmer (1980 in a thesis written at Humboldt State University listed the following parasites from Thomomys bottae (Eydoux & Gervais): Ransomus rodentorum, Trichuris fossor, Hymenolepis citelli, and an unidentified species of Heligmosomoides Hall, 1916. He also discussed the biological characteristics and taxonomy of R. rodentorum (some of his specimens are now in the Manter Laboratory Parasite Collection). Gardner and Jasmer (1983) described Heligmosomoides thomomyos Gardner & Jasmer, 1983 from Thomomys bottae (Eydoux & Gervais) and T. bulbivorus (Richardson) from Humboldt County, California and Benton County, Oregon, respectively. They included some measurements and remeasurements of two other species of Heligmosomoides: H. longispiculatus (Dickmans, 1940) and H. montanus Durette-Desset, 1968. Gardner (1985 described Hymenolepis tualatinensis from the duodenum of the Camas pocket gopher, Thomomys bulbivorus (Richardson, 1829) collected near the Tualatin River in the Willamette Valley of Oregon. In the report, several helminth species were documented during the study including Arostrilepis horrida also from the small intestine, Trichuris fossor from the cecum, Ransomus rodentorum from the cecum, and Heligmosomoides thomomyos from the duodenum. Gardner and Schmidt (1986) described Litomosoides thomomydis from the abdominal cavity of the Northern pocket gopher, Thomomys talpoides, and Botta's pocket gopher, Thomomys bottae, from Huerfano County, Colorado. Also, L. westi was described from the abdominal and pleural cavities of the Plains Pocket Gopher, Geomys bursarius, collected from Weld County, Colorado.
Using molecular methods, Haukisalmi et al. (2010) documented Hymenolepis weldensis from Geomys bursarius collected from Illinois and Indiana. Makarikov et al. (2012) described Arostrilepis schilleri obtained from the Camas pocket gopher, Thomomys bulbivorus, captured southeast of Corvallis, Oregon and originally reported as H. horrida by Gardner (1985). LeBrasseur (2017) in an unpublished master's thesis reported a study focused on the endoparasites of four species of pocket gophers in the genus Geomys collected from eight counties in Texas. These host species included the Plains pocket gopher, Geomys bursarius, Attwater's pocket gopher, G. attwateri Merriam, 1895, Texas pocket gopher, G. personatus True, 1889, and the Central Texas pocket gopher G. texensis Merriam, 1895. In addition, she found an unidentified Hymenolepis Weinland, 1858 obtained from G. attwateri, G. bursarius, and G. texensis and another tapeworm, Monoecocestus was obtained from G. bursarius¸ and G. texensis. Finally, a nematode species, Protospirura ascaroidea, was found from all four species of Geomys mentioned above; the specimens were verified by HWML personnel (LeBrasseur 2017).
Gardner et al. (2020) (Douthitt, 1915) was found from the small intestine of Hall's pocket gopher, Geomys jugossicularis Hooper, 1940 collected from Grama grass habitat, Keith County, Nebraska in 2016 (NP2661). Also, from 2009-2016, necropsies of Geomys lutescens Merriam, 1890 yielded many individuals of Litomosoides westi Gardner & Schmidt, 1986 from their abdominal cavities with individuals of Ransomus rodentorum from the cecum, and from two pocket gophers Physaloptera limbata Leidy, 1856 was found (NP2297, NP2298). Also, during general collecting in the area of Nebraska, we found two nematode species (R. rodentorum, and T. fossor -refer to NP1524) from the cecum of the Wyoming pocket gopher, Thomomys clusius Coues, 1875, collected from 5 miles east of Woods Landing, Albany County, Wyoming in 2013. All specimens mentioned in this work are deposited in the HW Manter Laboratory of Parasitology Museum collection where NP refers to the field collection number.

Endoparasites of Neotropical subterranean rodents
See graphical summary in Fig. 4 and endoparasite list Table 5. Khalil and Vogelsang (1931) described the first helminth parasite from a subterranean host from Neotropical region, Paraspidodera americana Khalil & Vogelsang, 1931 from the cecum of a single individual of what they called Ctenomys magellanicus Bennett, 1836 collected from Carrasco near Montevideo, Uruguay in 1927. The identifica-tion of this mammal specimen was probably erroneous as C. magellanicus occurs only near the Strait of Magellan in southern Argentina). Unfortunately, no hosts or parasite specimens were deposited in any collection that we can find up to the current time. Dollfus (1960) described Taenia talicei Dollfus, 1960 from the abdominal cavity of the Collared tuco-tuco, Ctenomys torquatus Lichtenstein, 1830, collected from Uruguay and in 1986, multistrobilate larvae of T. talicei were collected from several Ctenomys opimus at 7 km S: 4 km E. Cruce Ventilla, Oruro, Bolivia by a party from the American Museum of Natural History and the Museum of Southwestern Biology (Anderson 1997). Olsen (1976) described Monoecocestus torresi obtained from the small intestine of Maule's tuco-tuco, Ctenomys maulinus Philippi, 1872 collected near Lonquimay, Chile. Meanwhile, Torres et al. (1976) reported Paraspidodera uncinata Rudolphi, 1819, and unidentified Trichuris are reported from Maule's tuco-tuco, Ctenomys maulinus, collected from Chile. Babero and Cattan (1980) described Graphidiodes yañezi from the small intestine of a coruro, Spalacopus cyanus (Rodentia: Octodontidae), collected from near Concón, Chile. Babero and Murua (1987) described a new species of whipworm, Trichuris fulvi obtained from the cecum of the Tawny tuco-tuco, Ctenomys fulvus Philippi, 1860, collected from San Pedro Atacama, Tarapaca province, Chile. Lambert et al. (1988) described four new coccidian parasites in the genus Eimeria Schneider, 1875 recovered from the feces of the Highland tuco-tuco, Ctenomys opimus Wagner, 1848, trapped from several localities of the Department of Oruro, Bolivia, South America. Those species are E. granifera from Rancho Huancaroma, near the Rio Desaguadero, E. montuosi, from the north of Pomata Ayte, Rio Barros, E. opimi, and E. oruroensis, from the northeast and east of Rancho Huancaroma. Babero and Murua (1990) described Trichuris robusti from the cecum and large intestine of the Tawny tuco-tuco, Ctenomys fulvus, collected from La Hauyca, Tarapaca province, Chile. Gardner and Duszynski (1990), during a study on morphometric comparison of a coccidian species, Eimeria opimi Lambert et al., 1988, in different regions of Bolivia, the following host species were detected positive for this protozoan parasite. Those hosts include Lewis's tuco-tuco, Ctenomys lewisi Thomas, 1926, collected from the areas of the high-altitude region in Tarija; the Reddish tuco-tuco, Ctenomys frater Thomas, 1902, collected from medium latitude region of Tarija; the Conover's tuco-tuco, Ctenomys conoveri Osgood, 1946, collected from Chaco thorn forest area in Chuquisaca; the Bolivian tuco-tuco, Ctenomys boliviensis Waterhouse, 1848, and the Steinbach's tuco-tuco, Ctenomys steinbachi Thomas, 1907 collected from the Tropical palm/savanna region of Santa Cruz, Bolivia. In addition, the following coccidian parasites were reported from the Highland tuco-tuco, Ctenomys opimus. These species include Eimeria opimi, E. granifera Lambert et al., 1988, E. oruroensis Lambert et al., 1988, and E. montuosi Lambert et al., 1988 collected from the Oruro region E. opimi and E. granifera collected from the Potosi region. Suriano and Navone (1994) described Trichuris bursacaudata obtained from the cecum of the Talas tuco-tuco, Ctenomys talarum Thomas, 1898 collected from Punta Indio, Buenos Aires, and T. pampeana found in the cecum of the Azara's tuco-tuco, Ctenomys azarae Thomas, 1903, collected from Santa Rosa, La Pampa, Argentina (Suriano and Navone 1994). However, T. pampeana has been redescribed from its original voucher specimens (Rossin and Malizia 2005). Brant and Gardner (1997) described Litomosoides andersoni and L. ctenomyos from the abdominal and thoracic regions of the Highland tuco-tuco, Ctenomys opimus, collected from near Rancho Huancaroma, Departamento de Oruro, Bolivia. Rossin and Malizia (2002), during a study of the relationship between helminth parasites and demographic attributes of a population, two unidentified helminth parasites were reported. Those include Heligmostrongylus Travassos, 1917 found in the small intestine, and Trichuris recovered from the cecum of the Talas tuco-tuco, Ctenomys talarum, collected from Necochea, Buenos Aires province, Argentina. Rossin et al. (2004a) reported larvae of Hydatigera (syn. Taenia) taeniaeformis from the peritoneal cavity and liver of the Talas tuco-tuco, Ctenomys talarum, trapped in the Table 5. Endoparasite species diversity from Neotropical subterranean rodents (Ctenomyidae and Octodontidae). Authorities are given for parasite and host species.
During an ecological study of helminth parasite infection parameters in two species of South American subterranean rodents of the genus Ctenomys, Rossin et al. (2010a) documented seven species of Endoparasites from two collection localities, species of hosts studied included the Southern tuco-tuco, C. australis Rusconi, 1934, from Necochea, Buenos Aires Province, and Talas tuco-tuco, C. talarum Thomas, 1898, from Mar de Cobo, Buenos Aires province, Argentina. Both species of tuco-tuco's harbored Trichuris pampeana in the cecum, Pudica ctenomydis Rossin et al., 2006 in the small intestine, and larvae of Taenia talicei in the abdominal cavity. Moreover, C. talarum had four additional species of helminths, including Graphidiodes subterraneus Rossin et al., 2005 in the stomach, Paraspidodera uncinata in the large intestine, and Strongyloides myopotami and Trichostrongylus duretteae Rossin et al., 2006 in the small intestine. Rossin et al. (2010b) redescribed the metacestode form of Taenia talicei obtained from the peritoneal cavity of two tuco-tuco species including the Southern tuco-tuco, Ctenomys australis Rusconi, 1934, and the Talas tuco-tuco, Ctenomys talarum, from Necochea, Paraje Las Grutas, Buenos Aires Province in Argentina.
The present study reports that during a biodiversity survey in Bolivia in 1986, Pudica pujoli Durette-Desset & Tcheprakoff, 1990 was found in a single specimen of the White-toothed tuco-tuco, Ctenomys leucodon Waterhouse, 1848, collected from near San Andreas de Machaca, Bolivia.