Chordodes albibarbatus Montgomery, 1898

Bolek, Matthew G., Schmidt-Rhaesa, Andreas, Hanelt, Ben & Richardson, Dennis J., 2010, Redescription of the African Chordodes albibarbatus Montgomery 1898, and description of Chordodes janovyi n. sp. (Gordiida, Nematomorpha) and its non-adult stages from Cameroon, Africa, Zootaxa 2631, pp. 36-50 : 39-41

Chordodes albibarbatus Montgomery, 1898

( Figures 1–3 )

1898. Chordodes albibarbatus Zool. Jahrb. Syst. 11: p 22 & p 29

Holotype: 1 partial male

Other material: 1 partial female

Material examined: NICM mid-body, and anterior and posterior ends of a partial specimen of adult male holotype WM4525 and partial specimen of adult female WM4526 deposited by Montgomery in the Philadelphia Academy of Natural Sciences.

Type locality: Unknown location in the Ogoou River in Gabon, west central Africa, with tributaries reaching into the Republic of the Congo, Cameroon and Equatorial Guinea.

Other localities: Unknown location around the Gabon River in West Africa.

Host: Undetermined orthopteran reported by Montgomery (1898b).

Redescription of holotype male: The body color is brown with mottled darker spots and prominent white tufts of filaments corresponding to crowned areoles cover most of the body ( Figs. 1 A & C). The anterior end is lighter in color and no dark collar is present ( Fig. 1 A). Lighter coloration blends into the normal coloration of the remaining body. Body length according to Montgomery (1898a) is 223 mm and the midbody diameter is 1.25 mm. The anterior end is distinctly tapering ( Fig. 1 A); the posterior end is round with the indication of two lobes and the cloacal opening is subterminal and oval ( Fig. 1 B).

The body cuticle contains five types of areoles. Simple areoles are the most abundant, they are low (6–7 µm), oval and 10– 14 x 7–9 µm in length and width, with a warty surface (blackberry type) ( Fig. 1 D). Simple areoles are separated by interareolar furrows, 2–5 µm apart. Scattered among the simple areoles are bulging, tubercle, and pairs of crowned areoles surrounded by circumcluster areoles ( Figs. 1 E, 1F & Figs. 2 A, 2B, 2C, 2D). Bulging areoles form clusters of two, three or four areoles ( Figs. 1 E, 1F). Bulging areoles are taller (11– 18 µm) then simple areoles and are 13– 17 x 10–14 µm in length and width ( Figs. 1 E, 1F). Filaments on tubercle areoles are club shaped 14 µm (13–15) in length and approximately 1–2 µm in width at the base and become wider 3–4 µm distally ( Fig. 2 D). Crowned areoles occur in pairs ( Figs. 1 E, 1F & Figs. 2 A, 2B). Crowned areoles are 15–25 µm tall, 17–22 µm in length and 15–17 µm wide and contain apical filaments that are 35–60 µm in length on top ( Figs. 2 A & 2C). Crowned areoles are surrounded by 19–22 circumcluster areoles ( Figs. 1 E, 1F & Figs. 2 A, 2B, 2C). These areoles are taller (11–25 µm) than simple areoles, with small bristles on top; the tallest and thickest in diameter circumcluster areoles are positioned next to the crowned areoles, and decrease in length and diameter away from the central crowned areoles ( Figs. 1 E, 1F & Figs. 2 A, 2B, 2C).

Redescription of female: The body color is dark brown with the anterior and posterior ends being lighter in color; with no dark collar present on the anterior end ( Figs. 3 A, 3B). The lighter coloration blends into the normal coloration of the remaining body. Body length according to Montgomery (1898a) is 215 mm, and the diameter is 2 mm midbody. The anterior end is distinctly tapered ( Fig. 3 A); the posterior end is distinctly swollen, and the cloacal opening is terminal ( Fig. 3 B).

Unlike the males, the body cuticle of the female contains six types of areoles. Simple areoles are the most abundant, they are low (4–7 µm), oval and 10– 14 x 7–8 µm in length and width; with a warty surface (blackberry type; Fig. 3 D). Simple areoles are separated by interareolar furrows, 2–5 µm apart. Scattered among the simple areoles are bulging, tubercle, thorn, and crowned areoles surrounded by circumcluster areoles ( Figs. 3 E, 3F, 3G, 3H). Bulging areoles are single or form clusters of two, three or four areoles ( Fig. 3 E). Bulging areoles are taller (14–17 µm) then simple areoles and are 13– 28 x 8–10 µm in length and width. Filaments on tubercle areoles of the female are less club-shaped than in the male; they are 10 µm (9–12) in length and approximately 2 µm in width at the base and become wider 3–4 µm distally ( Fig. 3 H). Thorn areoles are 28–30 µm tall and 9–10 µm in diameter at the base ( Fig. 3 G). Crowned areoles occur in pairs ( Fig. 3 F). Crowned areoles are 21–23 µm tall, 15–23 µm in length and 11–17 µm wide and contain apical filaments that are 60–120 µm in length on top. Crowned areoles are surrounded by 14–22 circumcluster areoles. These areoles are taller (15–20 µm) than simple areoles, with small bristles on top; circumcluster areoles are thinner than in the male being 4–8 µm in length and 3–7 µm in width.

Comments: Our reinvestigation of C. albibarbatus indicates that it is distinct from other known species of African Chordodes . Montgomery (1898a, b) originally described areoles that correspond to simple, crowned, circumcluster, tubercle, and bulging areoles on the male and simple, crowned, circumcluster, tubercle and thorn areoles on female C. albibarbatus , and later Montgomery (1898b) indicated that thorn areoles were present on the male, but they were less numerous than on the female. One major difference in our redescription of C. albibarbatus from the original deiscription of Montgomery (1898a, b) was our discovery of bulging areoles on the female and our inability to find thorn areoles on the male. Additionally, we confirm that the simple areoles are of the blackberry type.

Of the 33 described species of Chordodes from Africa, 15 species are considered species inquirenda ( Schmidt-Rhaesa et al. 2008). However, of the remaining 18 African species of Chordodes , C. albibarbatus is most similar to Chordodes gariazzi Camerano, 1902a and Chordodes heinzei Sciacchitano, 1937 both described from the Democratic Republic of the Congo. Chordodes gariazzi contains six types of areoles including simple “blackberry”, groups of two to four bulging, tubercle, thorn, and pairs of crowned areoles surrounded by 12–20 circumcluster areoles, but differs from C. albibarbatus in the presence of two rows of bristle fields anterolateral to the cloacal opening in male C. gariazzi . Chordodes heinzei has five types of areoles including simple “blackberry”, isolated or clusters of two to four bulging areoles, club shaped tubercles, and pairs of crowned areoles surrounded by 17–24 circumcluster areoles (Zanca et al. 2006). The only apparent difference between male C. albibarbatus and C. heinzei , is based on the original description of thorn areoles on male C. albibarbatus by Montgomery (1898b). Unfortunately, Montgomery’s permanent slide of the cuticle of a male C. albibarbatus is lost and we cannot refute or confirm his observation of thorn areoles on the male of C. albibarbatus . It is premature to synonymize C. heinzei with C. albibarbatus until a female C. heinzei is described, more specimens are available for comparison, and/or molecular sequences are available to differentiate or synonymize these species.

Figures

FIGURE 1. Holotype of male Chordodes albibarbatus. (A) Tapering anterior end with a white cap, and no dark collar. Note the white tufts representing crowned areoles. Scale bar = 500 μm. (B) Posterior end. Note the posterior end is round with the indication of two lobes; oval cloaca (arrow). Scale bar = 500 μm. (C) Steriomicroscope, overview of midbody region showing the spotted pattern and distribution of crowned areoles. Scale bar = 750 μm. (D) NICM showing close up of simple “ blackberry ” areoles. Scale bar = 14 μm. (E & F) NICM overview of cuticle showing simple areoles and clusters of bulging areoles (black arrows) and crown areoles surrounded by circumcluster areoles (white arrows). Scale bar = 90 μm.

FIGURE 2. Cuticular structures of male Chordodes albibarbatus. (A) NICM surface view of pair of crowned areoles showing filaments. Scale bar = 30 μm. (B) NICM pair of crown areoles surrounded by circumcluster areoles. Scale bar = 30 μm. (C) NICM lateral view of crown areoles surrounded by circumcluster areoles. Scale bar = 30 μm. (D & Inset) NICM club shaped tubercle areole among simple areoles. Scale bar = 10 μm.

FIGURE 3. Cuticular structures of female Chordodes albibarbatus. (A) Tapering anterior end with a white cap, and no dark collar. Scale bar = 500 μm. (B) Steriomicroscope, posterior end. Scale bar = 500 μm. (C) Steriomicroscope, overview of midbody region showing the distribution of crowned areoles. Scale bar = 750 μm. (D) NICM showing close up of simple “ blackberry ” areoles. Scale bar = 5 μm. (E) NICM showing a close up of a cluster of three bulging areoles (black arrows) among simple areoles. Scale bar = 10 μm. (F) NICM showing a pair of crowned areoles surrounded by circumcluster areoles. Scale bar = 10 μm. (G) NICM showing a close up of a thorn areole. Scale bar = 10 μm. (H) NICM showing a close up of a tubercle areole. Scale bar = 5 μm.