Pristionchus dorci, Kanzaki & Herrmann & Weiler & Röseler & Theska & Berger & Rödelsperger & Sommer, 2021

Kanzaki, Natsumi, Herrmann, Matthias, Weiler, Christian, Röseler, Waltraud, Theska, Tobias, Berger, Jürgen, Rödelsperger, Christian & Sommer, Ralf J., 2021, Nine new Pristionchus (Nematoda: Diplogastridae) species from China, Zootaxa 4943 (1), pp. 1-66 : 53-55

Pristionchus dorci n. sp.

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Etymology. The species name is derived from the generic name of the host Lucanid beetle ( Dorcus davidis [Fairmaire, 1887]).

Measurements. See Table 6

Adult. General characters are as described above for maupasi -group.

Stenostomatous form. Dorsal movable tooth flint-shaped with anterior end slightly curved; left subventral ridge with three minute, blunt or pointed and adventitious denticles on a plate, most dorsal denticle often masked by middle denticle; right subventral ridge with a distal pointed adventitious denticle.

Eurystomatous form. Dorsal movable tooth claw-like as typical of the genus; left subventral ridge with three large plates, often with two or three split tips; right subventral movable tooth claw-like and extra peak not observed.

Male. As described above for maupasi -group.

Female. As described above for maupasi -group.

Diagnosis and relationships. Pristionchus dorci n. sp. is characterized by the slightly anteriorly curved flintshaped dorsal tooth, the left subventral ridge with three pointed or blunt denticles and right subventral ridge with a small pointed denticle of stenostomatous form, claw-like right subventral stegostomal tooth without an extra peak in eurystomatous form, the arrangement of male genital papillae, <v1, v2, v3d, co, v4, ad, ph, (v5, v6, v7, pd)> where posterior four paired papillae are forming cluster, and a long tail of both sexes. The maupasi- group of Pristionchus currently contains 15 species. These species are typologically similar with each other, but can be distinguished by the stomatal characters, e.g., number of denticles, and the arrangement of genital papillae (summarized in Kanzaki et al. 2018). P. dorci n. sp. shares its single-peaked right subventral ridge in the stenostomatous form and the laterally directed third paired male genital papillae (v3d) with P. laevicollis Kanzaki, Herrmann, Yoshida, Weiler, Rödelsperger & Sommer, 2018 , P. japonicus Kanzaki, Ragsdale, Herrmann, Mayer & Sommer, 2012 and P. hongkongensis Kanzaki, Herrmann, Yoshida, Weiler, Rödelsperger & Sommer, 2018 , which have single-peaked right subventral ridge and v3d papillae. The new species is also similar to P. maxplancki Kanzaki, Ragsdale, Herrmann, Röseler & Sommer, 2013 and P. quartusdecimus Kanzaki, Ragsdale, Herrmann, Röseler & Sommer, 2013 which has 1–2 peaks on the right subventral ridge and v3d papillae. However, P. dorci n. sp. is distinguished from P. laevicollis by the relative position of genital papillae, v2 and v3d two pairs are close to each other vs. clearly separated, the v3d is at 1/3 CBD anterior to co vs. very close to co and sometimes adcloacal, and the ventral triplet papillae and pd overlap each other vs. pd is located at just posterior to the triplet papillae. P. dorci n. sp. is distinguished from P. japonicus by the relative position of genital papillae, v1 is at 1.5 CBD vs. 1.0 CBD anterior to co, v1–v2 distance is almost same as vs. obviously shorter than v2–v4 distance, and female tail elongated conoid with vs. without filiform terminus. The new species is also readily distinguished from P. hongkongensis by the relative position of genital papillae, v1 is at 1.5 CBD vs. 1 CBD anterior to co, v1–v2 equivalent vs. shorter than v2–v4 distance, and the spicule shape, the spicule of P. dorci n. sp. is slenderer than that of P. hongkongensis . In addition, P. hongkongensis is characterized by its stomal morphology of eurystomatous form, i.e., large and barrel-shaped stoma bearing left subventral ridges with many cusps, and this character is clearly different from the stomal morphology of new species. P. dorci n. sp. is distinguished from P. quartusdecimus by the right subventral ridge of stenostomatous form, with single vs. 1-2 peaks, and relative position of genital papillae, v1 is at 1.5 CBD vs. 1.0 CBD anterior to co, v1–v2 distance is almost same as vs. obviously shorter than v2–v4 distance, and the ventral triplet papillae and pd overlap to each other vs. pd is located at just posterior to the triplet papillae. Typological characters, e.g., the arrangement of genital papillae, of new species is very similar to those of P. maxplancki . However, P. dorci n. sp. is distinguished from P. maxplancki by the right subventral ridge of stenostomatous form, with single vs. 1–2 peaks, and the relative position of posterior four paired papillae, the ventral triplet papillae and pd overlap to each other vs. pd is located at just posterior to the triplet papillae. Further, the new species is distinguished from all other species by mating experiments and also characterized by a ca. 1,600-bp fragment of the SSU rRNA gene (GenBank accession number MW017218 ), the sequence of which is distinct from that of all other Pristionchus species.

Type host and locality. Isolated from a specimen of the lucanid beetle Dorcus davidis collected at a dumpster near Ganquan, Shasnxi province, PRC .

Type material and type strain. Type strain RS 6134, other strain RS5992; frozen at the nematode collection of the MPI Tübingen and available as living culture upon request. Voucher specimens sent to the following museums: Holotype male, Paratype male and female: Museum für Naturkunde Karlsruhe , Germany ; Paratype male and female: Swedish Natural History Museum, Stockholm, Sweden ; Paratype male and female: University of California in Riverside Nematode Collection ( UCRNC), Riverside , CA, USA .