Trichocerca taurocephala ( Hauer, 1931 )

Min, Hee-Min Yang and Gi-Sik, 2025, Seven monogonont rotifers newly recorded in Korea (Rotifera: Monogononta), Journal of Species Research 14 (1), pp. 106-115 : 113-114

Trichocerca taurocephala ( Hauer, 1931) ( Figs. 6B , 7B )

ǐĦNflḆệ ( ljạ)

Diurella taurocephala Hauer, 1931: p. 173 , fig. 1.

Table 3. Genetic distance of Trichocerca using COI gene.

Material examined. Female, glycerol permanent slide ( NIBRIV0000919541 , NIBRIV0000919545 ). Pond in Incheon ( 37°24 ʹ 24.00 ʺ N, 126°44 ʹ 42.2 ʺ E), 06 Jun. 2021. Collected by Hee-Min Yang .

Diagnosis. Body short and stubby, 140 μm in length. Head with two unequal length of spines, right spine larg- er than left. Foot conical and short, with two toes. Toes unequal in length, right toe less than 1/2 of left toe. Left toe 50 μm and right toe 23 μm in length. Two toes curved ventrally. One cerebral red eyespot present. Trophi asymmetrical, 34 μm in length. Fulcrum long and straight, with crutched expansion on distal end. Alula of right ramus sharp and pointed posteriorly. Alula of left ramus larger than right alula and angled 90° from trophi axis. Left manubrium much larger than right ramus, thick and curved inward, 27 μm in length. Right ramus simple rod shape, slightly curved inward, 20 μm in length.

Distribution. Austria ( Jersabek, 1996), Belgium ( Segers, 1998), Czech Republic ( Devetter et al., 2020), Germany ( Hauer, 1931), India ( Sharma and Sharma, 2019), Mongolia ( Jersabek, 2010), Poland ( Jekatierynczuk-Rudczyk and Ejsmont-Karabin, 2023), Russia ( Kutikova, 1970), Turkey ( Ustaoğlu et al., 2012), Korea (This study).

Remarks. Trichocerca taurocephala is most similar to T. pygocera (Wiszniewski, 1932) in having a stubby body, two anterior spines of unequal length, and similar trophi characteristics. However, T. pygocera possesses a small spine at the posterior end of the body, whereas T. taurocephala lacks this feature. Additionally, the left manubrium alula of T. pygocera has small spines on the central side of the trophi, a feature absent in T. taurocephala . Trichocerca taurocephala also shares similarities with T. insolens (Myers, 1936) , T. mucosa (Stokes, 1896) and T. pediculus Remane, 1949 , all of which possess two anteri- or spines of unequal length and similar trophi characteristics. However, T. taurocephala can be distinguished from T. insolens by its elongated posterior body margin. It also differs from T. mucosa by the absence of spines on the anterior margin. Additionally, T. taurocephala is distinct from T. pediculus by the characteristics of the left manubrium alula and the presence of a small spine on the posterior body margin ( Koste, 1978; Shiel and Koste, 1992).

Molecular analysis. Genomic DNA was extracted from a single specimen and the partial COI sequence was obtained (759 bp, PQ594395). The genetic distances among Trichocerca species are presented in Table 3.

Figures

Fig. 6. Line drawing of habitus. A. Trichocerca cavia (Gosse, 1886), lateral view; B. Trichocerca taurocephala (Hauer, 1931), lateral view.

Fig. 7. SEM images of trophi.A. Trichocerca cavia (Gosse, 1886); B. Trichocerca taurocephala(Hauer, 1931).