[2] Phylogenetic analysis has been conducted on two known species of Mediorhynchus and confirmed the placement along with the related genus Gigantorhynchus in the family Gigantorhynchida.

[8] Males in some species possess eight cement glands which are used to temporarily close the posterior end of the female after copulation.

[10][11][a] M. africanus has been found parasitizing the helmeted guinea fowl (Numida meleagris) in Kruger National Park, South Africa, Morocco, Nigeria (reported as Numida ptilorhyncha) and Burkina Faso, and the Yellow-necked spurfowl (Pternistis leucoscepus) in Kenya.

[3] It is synonymous with Empodius segmentatus (de Marval, 1902) Southwell et MacFie, 1925 and Mediorhynchus selengensis Harris 1973.

There are up to 100 annuli (structures that permits shortening and lengthening of the body by telescoping) in females but fewer in the shorter males.

The hooks posteriorly directed and measure between 35 and 76 long with the smallest found anteriorly and the longest in the middle.

The female reproductive system is short and located in the broad and flat posterior end of trunk.

The uterine bell contains many large nucleated cells with its dorsal and ventral anterior ends connected to body wall with filaments.

[3] M. cambellensis has been found infesting the intestine of an oriole and flycatcher on Great Nicobar Island.

This worm closely resembles M. armenicum but differs from it in number of proboscis hooks and extent of lemnisci.

[12] M. centurorum was found in the egg and larval forms in Pennsylvania wood cockroach (Parcoblatta pensylvanica).

Cystacanths fed to starlings (Sturnus vaulgaris), and red-winged blackbirds, Agelaius phoeniceus, did not produce infections.

[17] M. emberizae is found infesting the intestines of the red-cowled cardinal (Paroaria dominicana) in the State of Bahia, Brazil.

[18] M. gallinarum is similar to M. africanus however specimens from Indonesia and elsewhere are cylindrical and non-segmented, the proboscis has 18 to 22 longitudinal rows of four to five hooks[18] and lacks prominent apical pores, sensory pits are rare on the trunk, the posterior end of the female is pointed with a terminal gonopore, and the eggs are smaller.

[3] M. gibsoni was found infesting the White-eyed buzzard (Butastur teesa) in Karachi, Sindh, Pakistan.

The proboscis has about 14 longitudinal rows of five hooks with a maximum body length of 11 cm found in a female.

[18] M. grandis has been found in the small intestine of the Common grackle (Quiscalus quiscula) in Maryland, New Jersey, Kansas, Illinois, Kentucky, the American crow (Corvus brachyrhynchos) in Maryland and Ohio, Eastern meadowlark (Sturnella magna) in North Carolina, Ohio, Illinois, Oklahoma, and Texas, Red-winged blackbird (Agelaius phoeniceus)) in Ohio and Texas, Rusty blackbird (Euphagus carolinus) in Illinois, Brown-headed cowbird (Molothrus ater) in Texas, the Saltmarsh sparrow (Ammospiza caudacutus) or a Nelson's sparrow (Ammospiza nelsoni)[c] in Texas and the American robin (Turdus migratorius) in Ohio.

[28] M. mattei has been found in the digestive tract of the Northern red-billed hornbill (Tockus erythrorhynchus) which is the type-host in Senegal.

It was described in 1982; its name honours French zoologist Xavier Mattei who collected the birds containing this acantocephalan used to identify the species.

[18] M. micranthus was found infesting the Eurasian skylark (Alauda arvensis) and the Crested lark (Galerida cristata) in the Golestan Province of Iran.

[30] It was found infesting a Karoo Thrush bird (Turdus smithi) in Polokwane, Limpopo Province.

[18] In an aviary setting, M. orientalis was found infesting the purple starling (Lamprotornis purpureus), Rüppell's starling (Lamprotornis purpuroptera), and the Bali myna (Leucopsar rothschildi) with the intermediate hosts being the Surinam cockroach (Pycnoscelus surinamensis) and the American cockroach (Periplaneta americana).

[14] M papillosus was found infesting the rufous-collared sparrows, (Zonotrichia capensis) in northern and central Chile.

[39] M. robustus was found infesting the intestines of a Yellow-breasted chat (Icteria virens) in Washington, United States and the Long-tailed Meadowlark (Sturnella loyca) in the Biobío Region, Chile.

[14] M. rodensis was found in the small intestine of the Eurasian jay (Garrulus glandarius) in Lakatnik in the Vrachanska Planina mountains of Bulgaria.

[41] M. sipocotensis was found parasitizing the American robin (Turdus migratorius) in Marion County, Indiana.

[16] M. taeniatus has been found infesting the African pied hornbill (Tockus fasciatus) in the Cote D'Ivoire.

[16] It has also been found infesting the helmeted guinea fowl (Numida meliagris) in Kimberley, Northern Cape Province, South Africa and the Southern Yellow-billed Hornbill (Tockus leucomelas) in Limpopo Province, South Africa.

[32] M. tenuis was found in the small intestine of the Common rock thrush (Monticola saxatilis) in the Iskarskoto defile in the Vrachanska Planina mountains of Bulgaria.

[14] M. zosteropis was found in the small intestine of the Hooded crow (Corvus cornix) in the Vratsa in the Vrachanska Planina mountains of Bulgaria and generally distributed in New Caledonia and the Palaearctic.