Chordodes

Schmidt-Rhaesa, Andreas & Karraker, Nancy E., 2017, Nematomorpha from Hong Kong and description of a new species from Malaysia, Zootaxa 4238 (3), pp. 395-405 : 396

Chordodes sp.

( Figure 1 )

Material examined. One male and one female from Peel Rise stream in Aberdeen Country Park, Hong Kong (Zone 50Q, 2464218N/206695E), elevation 172 m. Collected by N.E. Karraker on July 27, 2011. Deposited in the Zoological Museum Hamburg, accession numbers V13391 (male) and V13392 (female).

Description. The male is 285 mm long and has a diameter of 1.4 mm. The female is 405 mm long and has a diameter of 2.3 mm. The body color of both specimens is dark brown, and a pattern of darker patches (“leopard pattern”) is present. Simple areoles are irregular in shape and elevation ( Fig. 1 A). Their surface is generally smooth. Most areoles are round, but some display other forms, mostly a U-shaped form created by a kind of slit from the margin to about the center of the areoles ( Fig. 1 A, B). Tubercle areoles are present ( Fig. 1 A), and thorn areoles are rare, but present ( Fig. 1 B). At least in the male the thorns are apically curved. Bulging areoles are absent or are not recognized due to the irregular height of the simple areoles. Clusters of crowned areoles are present; these are composed of a central pair of crowned areoles and about 12 surrounding circumcluster areoles ( Fig. 1 C). Circumcluster areoles are more elevated than simple areoles and their apical surface is granulated ( Fig. 1 C). Crowned areoles contain a tuft of apical bristles of moderate length (about 20 µm) ( Fig. 1 C). Both sexes have crowned areoles with very long (> 100 µm in the male,> 200 µm in the female) apical filaments ( Fig. 1 D, E) along the ventral midline. The posterior end of the male corresponds to the general pattern in this genus, the ventral oval cloacal opening is surrounded by short circumcloacal spines and the ventral region around the cloacal opening contains many very short spines ( Fig. 1 F). The female posterior end is slightly inflated with a terminal cloacal opening, which also corresponds to the general pattern in the genus ( Fig. 1 G).

Remarks. The U-shaped form of simple areoles is a character that is thus far unreported in Asian nematomorphs. It is known from two South American species, Chordodes bouvieri (Villot, 1885) Römer, 1896 and C. peraccae (Camerano, 1894) Camerano, 1897 . In C. bouvieri this areolar shape is not evident in all descriptions (or in all specimens assigned to this species), but is figured in the SEM investigation by De Villalobos et al. (2009). In C. peraccae , this is documented by both Camerano (1897) and De Villalobos & Zanca (2001). Thorn areoles were not described from C. bouvieri and C. peraccae and in C. bouvieri also the crowned areoles with long apical filaments are not described. However, absence of structures in Chordodes specimens might be due to insufficient investigation, because structures may be scarce or because the pieces of cuticle examined were too small. Therefore we hesitate to describe the two specimens reported here as new species, although it appears quite unlikely that a single species is distributed in South America and Southeast Asia.

Figures

FIGURE 1. Chordodes sp. A. Cuticular structure of female showing simple areoles, part of which are U-shaped (arrows), and tubercle areoles (encircled). B. Cuticular structure of male with two thorn areoles (encircled). C. Crowned areole cluster composed of central crowned areoles and peripheral circumcluster areoles (ccar). D, E. Crowned areole cluster with very long apical filaments in the female. F. Posterior end of the male with ventral cloacal opening (co). G. Posterior end of the female with terminal cloacal opening (co). A, C – E, G from female (V 13392), B, F from male (V 13391).