Chordodes hawkeri Camerano, 1902

Zanca, Fernanda, Schmidt-Rhaesa, Andreas, Villalobos, Cristina De & Achiorno, Cecilia, 2006, Revision of the genus Chordodes (Gordiida, Nematomorpha) from Africa. II. Ultrastructural redescription of C. africanus Sciacchitano, 1933, C. hawkeri Camerano 1902; C. sandoensis, Sciacchitano 1937; C. schoutedeni, Sciacchitano 1933 and reinterpretation of Chordodes butensis Sciacchitano, 1937, Zootaxa 1191 (1191), pp. 49-59 : 52-55

Chordodes hawkeri Camerano, 1902

( Figure 2)

1902. Chordodes hawkeri . Camerano. Mus. Zool. Anat. Comp. Torino. 17: 1

Type series: 7 females; 2 males ( MRSNT G.37)

Type locality: Sudan, White Nilo

Material examined: Lectotype and paralectotype: SEM midbody and posterior end

Host: Undetermined mantis ( Camerano 1908) and Popa undata Fabr. ( Camerano 1915)

Description of the male lectotype: Anterior end tapered, the posterior end round, with two small lobe­like structures posterior to the cloacal opening and a medial ventral groove between them ( Fig. 2A). The cloacal opening is round and situated ventrally at 107µm distance from the posterior margin of the body. The cuticle around the cloacal opening is smooth.

The body cuticle shows five areolar types ( Fig. 2B). Simple areoles are the most abundant; they are low (2.5µm) with irregular shape, rounded or oval (5.8 to 7.5µm) have a roughly structured surface ( Figs. 2B, 2C, 2D). Scattered among the simple areoles there are tubercle areoles with an eccentric finger­like tubercle ( Fig. 2B), this tubercle is low (2.9µm) with a round apex. Other areolar types are bulging areoles, which are high (6.9µm), papillar or conical and with a smooth surface. Bulging areoles are arranged either isolated or forming groups of 2, 3, 5 up to 10 areoles ( Figs. 2B, 2C, 2D). Crowned areoles with very short filaments on top are arranged in an isolated form ( Fig. 2E). Loosely distributed are thorn areoles with a solid spine on top (5.6µm high) ( Fig. 2C). The interareolar furrow is structured into cord­like folds and there are scarcely distributed tubercles among simple areoles.

Description of the female lectoparatype: Anterior end tapered, the posterior end rounded with the cloacal opening terminal. The cuticle with the same characteristics of lectotype ( Fig. 2F).

Dimensions: Measurements of the lectotype and paralectotype specimens investigated are: male 73mm long, with a diameter about 0.4mm; female is 103mm long and 0.8mm thick. According to literature the body dimensions are variable: males vary in length between 60mm ( Camerano 1902) and 192mm ( Camerano 1908). Females range from 60mm ( Camerano 1902) to 250mm ( Camerano 1912). Diameters in midbody range from 0.3 ( Camerano 1902) to 0.8 ( Camerano 1902, 1908, 1912) in males and from about 0.4 ( Camerano 1902) to 1.5mm ( Camerano 1912) in females.

Comments: Camerano (1902) describes the cuticle of C. hawkeri with four areolar types, corresponding to simple, bulging, crowned and thorn areoles from our investigation. Camerano (1902) described crowned areoles to occur isolated or in clusters of 20, 30 areoles but our SEM investigation shows that crowned areoles are scarce and only distributed in an isolated way. Also, we can add one further areolar type, the tubercle areoles. Camerano (1902) pointed out differences in relation with the cuticle of the males and the females based on the size of crowned areoles, which are bigger in females and on the size of thorn areoles, which are longer and wider in the males. By SEM, this sexual dimorphism was not observed.

Distribution: Sudan, Nilo Blanco (7 females, 2 males, Camerano 1902); South Africa, Grahamstow (1 female, 3 males, Camerano 1908); Central Africa, Victoria Nyanza lake (on the Uganda­Tanzania­Kenya border) (2 females, Camerano 1912); Democratic Republic of the Congo, province Katanga (1 female, Camerano 1912); Republic of Sierra Leone (1 female, 1 male, Camerano 1912); Kenya, Mombasa (no data about number and sex of specimens, Camerano 1915).