Glypthelmins hyloreus Martin, 1969

León, Pérez-Ponce De, 2008, Taxonomic revision of the genus Glypthelmins Stafford, 1905 (Platyhelminthes: Digenea: Plagiorchiida), parasites of anurans in the Americas, Zootaxa 1882, pp. 1-45 : 32-34

Glypthelmins hyloreus Martin, 1969

( Figs. 21–22 )

Synonyms

Glypthelmins hyloreus Martin, 1969: 747 –752. Figs. 1–6 (Description and Life cycle); Hylotrema hyloreus, Sullivan (1972: 46) [This author transfers G. hyloreus to the genus Hylotrema ].

Taxonomic summary

Type-host: Hyla regilla .

Habitat: Intestine.

Type-locality: 5 Mi East Corvallis, Oregon, U.S.A.

Type specimens deposition: USNPC 70463.

Diagnosis: This species is differentiated by the following combination of traits: Pharynx smaller than ventral sucker, testes oblique and cirrus pouch curved. Vitelline glands extend anteriorly from caecal bifurcation to approximately midway between testes and tips of the intestinal caeca. Vitelline follicles caecal and extracaecal not confluent.

Description: Body elongated, with the maximum width in testicular region; anterior and posterior ends of the body are rounded. Tegument covered with small scale-like spines extending from anterior end to posterior end of body. Oral sucker subterminal, round, larger than pharynx and ventral sucker. Ventral sucker rounded, pre-equatorial. Oral sucker/ventral sucker length ratio 1:0.8. Prepharynx short, wider than long. Pharynx globose. Medial glands surround anterior and posterior margins of pharynx. Oesophagus thin, large, with external cell-glands on both sides. Caeca narrow, symmetrical. Testes oval, intercaecal, oblique, equatorial. Genital pore is located mid-ventral, just anterior to ventral sucker. Cirrus pouch slightly curved, larger than ventral sucker, containing bipartite seminal vesicle, followed by an elongated, large and unarmed cirrus. Ovary sinistral, oval, extends dorsally to posterior margin of ventral sucker. Seminal receptacle oval, usually posterodorsal to ovary. Uterus mostly intercaecal, with some loops extending to the caecal and extracaecal region. No uterine loops are located in the posterior end of body. Muscular metraterm opens into the genital pore. Vitelline gland follicular. Vitelline follicles commence at level of caecal bifurcation and extend to posterior margin of testes. Follicles are not confluent at any level. Eggs operculated, yellowish, and measure 47–52 µm long by 24–27µm wide. Excretory vesicle “I” shaped and extends to the level of testes. Excretory pore terminal.

Host, geographic distribution and specimen deposition

Hyla regilla : (= Pseudacris regilla ): U.S.A.: Near Corvallis, Linn County, Oregon ( Martin, 1969); Spokane County, Washington (Lang, pers. com. in O´ Grady 1987). Specimen deposition: USNPC: 70463, 70464.

Pseudacris triseriata : Canada: George Lake, Alberta, (Holmes, per. com. in O´ Grady 1987). U.S.A.: Colorado ( Ubelaker et al. 1967; Brooks 1976b); 3 miles south of Lincoln; 0.25 miles north of Davey; 5 miles south of Genoa; 8 miles south, 2 miles east of Humboldt; Peru; 2 miles west of Springview; 3 miles east of Valentine; 0.5 miles south, 1 mile west of Bloomington; 2 miles south, 1 mile west of Mead; 10 miles west of Lincoln, Nebraska ( Brooks, 1976b); Ogallala, Nebraska ( Rannala, 1990, 1991, 1992). Specimen deposition: HWML: 20080, 20209, 21334, 33823, 33824.

Life cycle

The life cycle was originally described by Martin (1969). Adults inhabit the intestine of hylid frogs ( Pseudacris ), and eggs are released with the feces of the host. Once in the water, eggs are ingested by the snail Lymnaea stagnalis (Lymneadae) . In the intestine, miracidium emerge from eggs and transform into mother and then daughter sporocyst in which gymnocephalan cercariae are formed. Cercaria are expelled from the snail and swim actively looking for the second intermediate host, tadpoles of Pseudacris regilla and P. triseriata . Once the cercariae contacts the skin of the hylids, they move along the surface to find the nasal cavities and then transform into metacercariae when they are in the mesentery of the host. Metacercariae remain unencysted until the molting process of the hylids. The route of metacercariae into the digestive tract has not been determined, but it has been speculated that metacercariae penetrate the intestinal wall due to its prominent penetration glands. In the intestine of the hylids, metacercariae develop into adults.

GenBank

cox 1: AY278059 (381 bp); 5.8s and ITS2: AY278066 (413); 28S: AY278050 (1274 bp).

Figures

FIGURE 1. Phylogenetic hypothesis of Razo-Mendivil et al. (2006) showing the placement of Glypthelmins, Rauschiella and Choledocystus within the Plagiorchiforms. The Glypthelmins clade is marked in red.

FIGURES 2 – 5. Glypthelmins quieta (Stafford, 1900) Stafford, 1905. 2. Mature specimen, ventral view ex Rana catesbeiana, Nebraska, U. S. A. (personal collection Dr. Daniel R. Brooks). Scale bar = 0.3 mm. 3. Detail of the anterior end showing the peripharyngeal glands ex Rana neovolcanica, Michoacán, Mexico (CNHE 3272) Scale bar = 0.1 mm. 4. Mature specimen, ventral view ex Rana spectabilis, Oaxaca, Mexico (CNHE 4689). Scale bar = 0.3 mm. 5. Immature specimen ex Rana montezumae, Estado de Mexico, Mexico (CNHE 3275). Scale bar = 0.3 mm.

FIGURES 6 – 8. Glypthelmins californiensis (Cort, 1919) Miller, 1930. 6. Mature specimen, ventral view ex Rana dunni, Michoacán, Mexico (CNHE 3282). Scale bar = 0.3 mm. 7. Detail of the anterior end showing medial glands around the pharynx ex Rana dunni, Michoacán, Mexico (CNHE 3282). Scale bar = 0.1 mm. 8. Detail of the terminal genitalia ex Rana dunni, Michoacán, México (CNHE 4682). Scale bar = 0.1 mm.

FIGURES 21 – 22. Glypthelmins hyloreus Martin, 1969. 21. Mature specimen, ventral view ex Pseudacris triseriata, Nebraska, U. S. A. (personal collection Dr. Daniel R. Brooks). Scale bar = 0.3 mm. 22. Detail of the terminal genitalia ex Pseudacris triseriata, Nebraska, U. S. A. (personal collection Dr. Daniel R. Brooks). Scale bar = 0.1 mm.