Gordius jorriti, Schmidt-Rhaesa, Andreas & Schwarz, Christian J., 2016

Schmidt-Rhaesa, Andreas & Schwarz, Christian J., 2016, Nematomorpha from the Philippines, with description of two new species, Zootaxa 4158 (2), pp. 246-260 : 247

Gordius jorriti n. sp.

( Figure 2 )

Holotype. One male from type locality, to be deposited in the PNM.

Etymology. The species name “ jorriti ” is chosen after one son of the senior author, Jorrit.

Type locality. Northwest Panay Peninsula , Sibaliw Research Station , Buruanga, Aklan, Panay Island, Philippines (11° 49.131' N, 121° 58.246' E), ~ 512 m; primary forest, found in a Barber trap; collected by C. Schwitzke on October 29, 2011.

Description. The holotype and only specimen is 345 mm long and measures 0.8 mm in width. It is dark brown in color, and a dark collar is present.

The cuticle is generally smooth ( Fig. 2 A); high magnification reveals a surface structure including minute bristles and some spine-like structures not exceeding 1 µm ( Fig. 2 B). The cloacal opening at the posterior end is not clearly visible, as it is filled with some material ( Fig. 2 C). The postcloacal crescent is parabolic ( Fig. 2 C), its anterior edge is 11 µm behind the cloacal opening. The two arms of the crescent extend onto the tail lobes, the maximal width of the postcloacal crescent is 290 µm. Anterior to the cloacal opening is a semicircular row of bristles ( Fig. 2 C). The region around the cloacal opening is somewhat deeper than the remaining parts, with a kind of ridge present at the row of bristles. Such depressions are probably artifacts after fixation with dehydrating reagents such as ethanol. The maximum width of the row of bristles is 388 µm, it is therefore broader than the postcloacal crescent. The posterior ends of the row are at the level of the anterior part of the postcloacal crescent. The vertex of the row is 83 µm anterior of the cloacal opening. The row contains longer unbranched bristles and shorter branched ones ( Fig. 2 D). Up to 6 branches were counted. On the posterior end of the tail lobes, stout bristles are present ( Fig. 2 E). Some large artefactual structures (labelled “art” in Fig. 2 C) occur in a few places on the posterior end.

Remarks. A row of bristles anterior to the cloaca is present only in two species, Gordius paranensis Camerano, 1892 and Gordius difficilis Smith, 1994 . Both species differ in the shape of the postcloacal crescent, which is angled in G. difficilis but round in G. paranensis . While G. difficilis occurs in North America (Schmidt- Rhaesa et al. 2003), G. paranensis is distributed in South America (see De Villalobos et al. 2005, 2009) and in New Zealand (see Schmidt-Rhaesa et al. 2000, Schmidt-Rhaesa 2008). As far as is known, the row of bristles in G. paranensis contains unbranched bristles ( Schmidt-Rhaesa et al. 2000, De Villalobos et al. 2009) or a few bristles with two branches (De Villalobos et al. 2005). This is a clear difference from G. jorriti , which has a number of strongly branched bristles. Another difference is the shape of the postcloacal crescent, which distinctly extends onto the tail lobes in G. jorriti , but is arcuate and only slightly extends onto the tail lobes in G. paranensis (Schmidt- Rhaesa et al. 2000, De Villalobos et al. 2005). Therefore, we regard G. jorriti as a distinct species.

Figures

FIGURE 2. Gordius jorriti n. sp., holotype. A. Smooth cuticle under low magnification. B. Fine surface structure including spine-like structures (encircled). C. Ventral view on posterior end with position of the cloacal opening (co) and the postcloacal crescent (pcc). Arrows point at the precloacal row of bristles, dotted squares indicate position of figures D and E. A large artefactual structure (art) is present on the cuticle. D. Fine structure of bristles, arrows indicate some branched bristles. E. Fine spines on the posterior margin of one tail lobe.