Genus Cylindropharynx Leiper 1911

General. Small to medium-sized Cyathostominae. MC flattened, divided into inner and outer rings. Posterior edge of MC posterior to edge of BC. Amphids not markedly projected through MC surface. Tip and longer stalk of submedian papillae extend through MC. Tip of submedian papillae spindle-shaped, about 4 or more times as long as thick. Stalk of submedian papillae longer than broad. ELC consists of six triangular elements unequal in size, four occupy a submedian position and are of equal, relatively small size, the two remaining leaves are much broader and situated laterally, each is usually notched at the apex and longitudinally grooved. Dorsally and ventrally the external leaf crown is deficient, but from each of the prominent dorsal and ventral lips of the mouth collar there projects horisontally inwards a broad crescentic plate, the free, concave margin of which is directed towards the axis of the mouth. Insertion point on tips of ILC, but slightly back from tips. 12 elements of ILC longer than broad, tips pointed; insertion less than ¼ of BC depth. Line formed by insertion of elements of ILC straight. Form of posterior edge of elements of ILC adorned with hooks or projections. Support for ELC surrounds anterior edge of BC, helmut-like. Septum intracoronare origin on support. Medial insertion of septum intracoronare situated at junction of ELC and ILC. Walls of BC concave, thicker in middle. Buccal cavity much deeper than wide, cylindrical. Dorsal gutter nipple- or button-like. Buccal teeth absent. Esophageal funnel moderately enlarged. Esophageal teeth prominent. Anterior muscular portion of esophagus less than 1/4 of length. Excretory pore posterior to NR. Anterior deirids near middle of glandular esophagus.

Male: proximal and middle branches of dorsal rays fused. Ventral rays shorter than laterals. Dorsal lobe equal laterals. Externodorsal rays origin at junction of dorsal and laterals. Gubernaculum small handle, enlarged distal tip. Genital cone elongate, extends beyond bursal edge. Spicule tips hook- or harpoon-shaped.

Female: Vulva 2-3, or more, tail lengths from anus. Vagina shorter than sphincter of ovejector. Ovejector vestibule T-shaped, infundibulum infundibulum longer than sphincter. Tail conical, short, less than 2x diameter at anus.

Type species: C. brevicauda Leiper, 1911.

Species inquirenda: C. rhodesiensis Yorke et Macfie, 1920

Discussion

Previously, eight species of the genus were described. Although they are common parasites of zebras, most species were described on the base of only a few specimens. Firstly, Leiper (1911) created the genus Cylindropharynx for two species from zebras in British East Africa (now Kenya). Leiper’s two species, C. brevicauda and C. longicauda, differed by size of buccal capsule, distance from vulva to tip of tail, spicule length and form of the external branch of the dorsal ray. Boulenger (1920) improved Leiper’s description by describing the ELC and ILC and was first to pay attention to the structure of the genital cone appendages. He described peculiar appendages for C. brevicauda, that consisted of a pair of finger-shaped appendages with rounded ends just behind the genital opening, and an irregular number of delicate pointed processes scattered over the dorsal surface of the cone. According to Boulenger, C. longicauda has a single pair of rather stout finger-shaped processes.

Yorke and Macfie (1920) described C. rhodesiensis, a large species of the genus with distance from vulva to tail tip 1.700-2.196 mm. The authors had only one male and five females and were not able to distinguish appendages of the genital cone. Theiler (1923) described C. intermedia, a species which differed from C. brevicauda by greater size and a vulva to tail tip distance of1.5-1.6 mm. According Theiler, C. intermedia differed from C. rhodesiensis by the nature of its genital cone. She noted that appendages of the genital cone in C. intermedia werethe same as in C. brevicauda. Approximately at the same time Cram (1925) described C. ornata. She also paid attention to structure of the ELC and apppendages of the genital cone. Now we can note, that Cram did not know about the description of C. intermedia.

Two species – C. aethiopica and C. asini were described from donkeys and mules in Ethiopia by Roetti (1947). This author himself noted that those species differ from C. brevicauda and C. longicauda correspodingly only in measurements. Lastly, C.dollfusi was described Le Van Hoa (1961). This species was described with an oval genital cone, without appendages, rounded tips of dorsal ray and, according the author, very similar to C. rhodesiensis from which it was distinguished by size.

We have studied all specimens of this genus which we were able to locate in museums around the world. That includes C. dollfusi from Paris museum of natural history, C. brevicauda from Berlin Museum , C intermedia from Onderstepoort Museum, C. brevicauda, C. longycauda and C. intermedia from British Museum and C. ornata from the U.S. National Parasite Collection. In addition, we have studied large numbers of specimens collected by R. C. Krecek from zebras. We were not able to locate types of C. asini, C.aethiopica or C. rhodesiensis. Two of these species were never found after their descriptions, and the last one was mentioned two times in faunistic lists (Le Roux, 1932 and van den Berghe, 1943).

We treat C.aethiopica and C. asini as synonyms of C. brevicauda and C. longicauda correspondingly, because of insignificant differences in measurements from these species.

C. rhodesiensis is very similar to C. intermedia. However, we consider it as species inquirenda because it differs from other species by the extremely large size of the body and buccal capsule and a lack of appendages on the genital cone.

The type specimens of C. ornata are mounted on slides in balsam and it is impossible to study these specimens. Considering: that this species was described when the author did not have information about the similar species, C. intermedia; that based on the drawing, the length of the buccal capsule is about 350 µm instead 300 listed in the text; and, that the appendages of the genital cone of C. intermedia can vary significantly, especially the pair of finger-shaped appendages (Krecek, 1984, our data); we treat C. ornata as a synonym of C. intermedia.

We also consider C. dollfusi to be a synonym of C. intermedia after studying thetype specimens. We have found, that this species also has at least scattered irregular numbers of delicate pointed processes over the dorsal surface of the genital cone. We do not consider other peculiarities, such as thickness of dorsal ray branches or shape of their tips to be useful characters because of their variability within species of Cylindropharynx.

We also have found both kinds of genital cone appendages in C. longicauda.