Pseudochordodes meridionalis Carvalho and Feio, 1950

Schmidt-Rhaesa, Andreas & Menzel, Lena, 2005, Central American and Caribbean species of horsehair worms (Nematomorpha), with the description of three new species, Journal of Natural History 39 (7), pp. 515-529 : 521-523

Pseudochordodes meridionalis Carvalho and Feio, 1950

( Figure 3 )

Pseudochordodes meridionalis Carvalho and Feio 1950: 202–203 .

Neochordodes meridionalis: de Miralles and de Villalobos 1996: 147 .

Material studied

Newly reported male from Tamanlipas, Mexico; LM and SEM.

Description

The newly reported male is 11.5 cm long and has a diameter of 0.4 mm. The body colour is dark brown. Darker, elevated areoles (see below) create a finely spotted pattern of the cuticle. The anterior tip is white, a dark collar is not present. The posterior end is round ( Figure 3E ). The cloacal opening is slit-like and surrounded by slender bristles. Further bristles are distributed in the ventral region around the cloacal opening ( Figure 3E ). The ventral face of the posterior end is structured by flat and homogeneous areoles, while the usual pattern of the cuticle starts at the ventrolateral margin of the posterior end. In the lateral and dorsal regions of the posterior end are numerous short tubercles which are lacking in the remaining body.

The cuticle contains two types of areole ( Figure 3A–C ). The first type is flat and polygonal. Areoles are separated by narrow interareolar grooves with short bristles. Very abundant are larger, darker and elevated areoles which occur either solitary or in clusters ( Figure 3A–C ). Similar to P. manteri , these large areoles often cluster in the megareolar pattern. The neighbouring areoles may fuse almost completely or remain separated by a fine suture or deeper groove ( Figure 3B ). The surface of the large areoles is smooth. When clusters occur, they are a combination of large areoles in the megareolar pattern and those without this pattern. Clusters may include seven and more areoles. In the ventral midline, there is a loose band of individual large elevated areoles ( Figure 3C, D ). A megareolar pattern does not occur in this region.

Comments

The newly reported specimen corresponds with the description of P. meridionalis by Carvalho and Feio (1950). It resembles P. manteri in some respects, but individual large elevated areoles are much more abundant in P. meridionalis , and the clusters are larger. De Miralles and de Villalobos (1996) concluded after a reinvestigation that only one type of areole is present in P. meridionalis which must therefore belong to the genus Neochordodes . However, we observe two kinds of areole, corresponding to the observation of a second type of ‘‘vestigial’’ areole in the first description ( Carvalho and Feio 1950) and to such a second type in the figures of de Miralles (1976). Therefore, the specimens investigated by de Miralles and de Villalobos (1996) might represent a different species, although they were sampled, at least in part, in the region where the holotype was collected.

Distribution

New record. Mexico: Tamanlipas , Sótano de San Marcos, one male, coll. 21 March 1998 by P. Sprouse (Texas Memorial Museum, Austin, USA, no accession number) .

Further distribution. Argentina (Carvalaho and Feio 1950; de Miralles 1976; de Miralles and de Villalobos 1996).

Figures

Figure 3. Pseudochordodes meridionalis. Light microscopical (A) and SEM (B) image of body cuticle showing clusters of dark and elevated areoles. (C, D). Distribution of areoles along the ventral midline, which is marked by smaller dark areoles (arrows in C). Midline runs from top to bottom in (C) and from left to right in (D). (E) Ventral view of male posterior end, white arrow indicates position of the cloacal opening. The larger white structure is pollution.