Tetranemertes Chernyshev, 1992

Abato, Jamael C., Hookabe, Natsumi & Kajihara, Hiroshi, 2025, Species Diversity of Tetranemertes (Nemertea: Monostilifera) in Japan, Species Diversity 30 (1), pp. 71-83 : 72-74

Tetranemertes Chernyshev, 1992

? Ommatoplea Ehrenberg, 1828 : pl. IV (type species Ommatoplea taeniata Ehrenberg, 1828 , fixed by monotypy).

Nemertes : Friedrich, 1955: 171 (neither Cuvier, 1816 nor Johnston, 1837) [ Nemertes antonina Quatrefages, 1846 indicated as type species (invalid designation)].

Tetranemertes Chernyshev, 1992: 134 (type species Nemertes antonina Quatrefages, 1846 , fixed by original designation).

Remarks. The three species names “ Ommatoplea taeniata ”, “ Polystemma adriaticus ”, and “ Polystemma albicans ”,

Tetranemertes ocelata MT 581159 MT581200 MT581186 MT578863 — Cherneva et al. (2023)

Tetranemertes pastafariensis isolate CB055 18 — MT581210 MT581196 MT578892 — Cherneva et al . (2023)

Tetranemertes pastafariensis isolate SMCP0019 MT581182 — — MT578896 — Cherneva et al . (2023)

Tetranemertes paulayi BOMAN 08291 — OQ322646 OQ322592 — — Cherneva et al. (2023)

Tetranemertes paulayi BOMAN 07013 — OQ322649 — OQ321715 — Cherneva et al. (2023)

Tetranemertes rubrolineata BOMAN 08038 — OQ322650 OQ322595 OQ321718 — Cherneva et al. (2023)

Tetranemertes sp. ETP001 MT581183 MT581211 MT581197 MT578897 — Cherneva et al . (2023)

Tetranemertes sp. AHK-2024-1 — — — PQ564663 — Present study

Tetranemertes sp. AHK-2024-2 — — — PQ564664 — Present study

Tetranemertes unistriata 4900709991 ( Japan) MT581158 MT581198 MT581184 MT578861 — Cherneva et al . (2023)

Tetrastemma elegans AJ 436810 — AJ436865 AJ436920 AJ436968 Thollesson and Norenburg (2003) Tetrastemma parallelos ON 112235 ON112234 ON112277 ON098244 ON107495 Abato et al. (2022)

Tetrastemma phaeobasisae MZ 231165 MZ231234 MZ231324 MZ216553 — Chernyshev et al.(2021)

Tetrastemma vittigerum 132742 KF935491 KF935323 KF935379 KF935539 KF935435 Kvist et al .(2014)

Tetrastemma vittigerum 25171 — KF935324 KF935380 KF935540 KF935436 Kvist et al .(2014)

Tetrastemma vittigerum H3 MZ231192 MZ231272 MZ231362 MZ216585 MZ216663 Chernyshev et al .(2021)

Tetrastemma wilsoni AJ 436811 — AJ436866 AJ436921 AJ436969 Thollesson and Norenburg (2003)

Vieitezia luzmurubeae 104801 JF277607 HQ443428 — HQ443426 JF277746 Andrade et al . (2012)

Vieitezia luzmurubeae 133470 KF935495 KF935328 KF935384 KF935544 KF935440 Kvist et al .(2014)

* Our phylogenetic analysis used one of the correctly identified or correctly labeled P. nelsoni sequences. The COI sequence with GenBank accession number HQ848606 labelled as P. nelsoni bio-material DNA105586 is an incorrectly identified or mislabeled sequence. This sequence is not from a true P. nelsoni as it is nested within Oerstediina whereas a true P. nelsoni should be in Amphiporina . Similarly, COI sequences with accession numbers MK047678 ( P. nelsoni isolate PROne nz13.) and MZ558353 ( Prosorhochmus sp. MNJ-2021) are not true congeners being nested outside the Prosorhochmus clade. This claim can be checked by constructing a COI neighbor joining tree.

as well as the two genus names “ Ommatoplea ” and “ Polystemma ”, appeared for the first time in the caption of plate IV (published in 1828) of Ehrenberg (1828 –1831); these names were made available in 1828 under Article 12.2.7 of the International Code of Zoological Nomenclature (hereafter the Code) ( International Commission on Zoological Nomenclature 1999) (hereinafter, ICZN refers to the Commission). In the text (published in 1831), P. albicans was transferred to the newly established genus Amphiporus Ehrenberg, 1831 . Interpreting the date of publication of Ommatoplea Ehrenberg, 1828 and Polystemma Ehrenberg, 1828 erroneously as 1831, Verrill (1892: 387) included these two names in the synonymy of Amphiporus , and, at the same time, recognized the two taxa as subgenera under Amphiporus ( Verrill 1892: 388) . Bürger (1904: 77) regarded Ommatoplea and O. taeniata as nomina dubia; Gibson (1995: 449, 451) followed this. On the other hand, Polystemma adriaticum and Polystemma albicans were considered invalid and listed—as valid names—as Amphiporus adriaticus and Amphiporus albicans ( Bürger 1904: 49; Gibson 1995: 486); however, when the priorities of Polystemma Ehrenberg, 1828 and Amphiporus Ehrenberg, 1831 are considered, these name usages are incorrect.

As Ommatoplea and Polystemma have unlikely been used as valid after 1898, while Amphiporus has been in prevailing usage, the precedence would be reversed under Article 23.9 of the Code (which is beyond the scope of this study, though). On the other hand, Ommatoplea may actually be a senior synonym of Tetranemertes , as some of the characteristics in O. taeniata —such as the ocelli arranged in four rows and the short rhynchocoel ( Fig. 1A–D )—suggest. If this is the case, the precedence would not likely be reversed, because the usage of Tetranemertes would not satisfy the conditions stipulated in Article 23.9.1.2 of the Code. Despite external morphological resemblance with Tetranemertes , our observation and opinion on Ommatoplea as a senior synonym of the former can be claimed with certainty only when fresh O. taeniata from the type locality is thoroughly examined, especially its stylet basis morphology and cephalic furrows, and subjected to a phylogenetic study.

Figures

Fig. 1. Ommatoplea taeniata Ehrenberg, 1828. A, Anterior end of body (Ehrenberg 1828–1831: fig. III f); B, C, entire animal (Ehrenberg 1828–1831: fig. III a, b); D, magnification of the head (Ehrenberg 1828–1831: fig. III d). Reproduced from a digitalized copy at Biodiversity Heritage Library (https://www.biodiversitylibrary.org/ item/189273#page/85/mode/1up).