Gordius serratus, Schmidt-Rhaesa, Andreas, 2010

Schmidt-Rhaesa, Andreas, 2010, Considerations on the genus Gordius (Nematomorpha, horsehair worms), with the description of seven new species, Zootaxa 2533, pp. 1-35 : 26

Gordius serratus sp. nov.

( Fig. 10A,B )

Type material: Holotype: 13, Zoological Museum Hamburg, ZMH V13280 .

Type locality. Papua New Guinea, from river water, Lahamenegu piggery, Goroka, Eastern Highlands Province (collected presumably in 1975, received by Ifor Owen).

Other material examined. Paratype: 13 from same location, same sample data: Zoological Museum Hamburg, ZMH V13281 .

Etymology. The name refers to the serrated anterior margin of the postcloacal crescent.

Description. The body color is very light brown; white spots and darker dorsal or ventral lines are absent. The holotype is 200 mm long, the paratype 195 mm. Their diameters are 0.7 and 0.6 mm, respectively.

The postcloacal crescent is very narrow (less than half of the diameter of the posterior end) and semicircular ( Fig. 10A,B ). It is directly at the point of bifurcation, the arms extend onto the tail lobes. The anterior margin of the postcloacal crescent is irregularly serrated in both specimens ( Fig. 10A,B ). The cloacal opening is round ( Fig. 10A ). The tail lobes are slightly shorter than twice their diameter, the inner side is not concave. Scattered tiny bristles are present on the entire posterior end. The cuticle is smooth and no bristles were observed.

Remarks. There are few species descriptions in which the postcloacal crescent is so strongly curved and narrow as in this species. Gordius horsti Camerano, 1895 from Borneo and G. salvadorii Camerano, 1895 from the “Greater Sunda Islands” ( Camerano 1895, 1897) both have poined tail lobes, which indicates that they should perhaps be transferred to Acutogordius . Gordius pallidus Linstow, 1906 from Korea and G. samoensis Linstow, 1906 from Samoa ( Linstow 1906a, b) both have a cuticle with areoles. The Papua New Guinea specimens are closest to G. lapponicus Linstow, 1906 from Sweden (Lapland) ( Linstow 1906a), but differ in the possession of tiny bristles in the posterior end and the serrated anterior margin of the postcloacal crescent. Therefore, the characters shown by the Papua New Guinea specimens are new and justify the description as a new species.

Figures

FIGURE 10. A, B. Gordius serratus sp. nov., C – F. G. z w i c k i sp. nov. A. Posterior end of holotype. B. Posterior end of paratype. C. Posterior end of paratype. D. Posterior end of holotype. E, F. Characteristic distribution of spines (arrow) posterior to the postcloacal crescent.