Tetranemertes antonina (Quatrefages, 1846)

Cherneva, Irina, Ellison, Christina I., Zattara, Eduardo E., Norenburg, Jon L., Schwartz, Megan L., Junoy, Juan & Maslakova, Svetlana A., 2023, Seven new species of Tetranemertes Chernyshev, 1992 (Monostilifera, Hoplonemertea, Nemertea) from the Caribbean Sea, western Pacific, and Arabian Sea, and revision of the genus, ZooKeys 1181, pp. 167-200 : 167

Tetranemertes antonina (Quatrefages, 1846)

Fig. 2

Nemertes antonina Quatrefages, 1846: 111; Diesing 1850: 274; Hubrecht 1879: 231; Joubin 1890: 590; Friedrich 1955: 171; Kirsteuer 1965: 315; Gibson 1982: 285.

Eunemertes antonina : Joubin 1894: 206; Bürger 1895: 38.

Emplectonema antonina : Friedrich 1955: 171.

Polia antonina : Hubrecht 1879: 231.

Material examined.

Type material was never designated, and it is very unlikely that either Quatrefages’ or Bürger’s specimens exist or can be found. With the purpose of improving nomenclatural stability, we designate the following specimen examined by us as the neotype: Indemares-Alborán Campaign Sample TE 3-DR23 (Fig. 2 ), collected by Juan Junoy on 25 September 2011 at the depth of 25 m; 35°55.93'N, 03°02.42'W. This specimen is preserved in Bouin’s and stored in 100% ethanol at the Museo Nacional de Ciencias Naturales (MNCN) in Madrid, Spain (Catalog number MNCN 5.02/28). The anterior portion of another individual (TE4-DR23) collected at the same station is stored in 95% ethanol at the Harvard Museum of Comparative Zoology (IZ-132747), and sequences have been published by Kvist et al (2014). See Table 1 for accession numbers, and Table 2 for collecting information .

Diagnosis.

Uniformly dark pink (wine) color of the body of living specimens distinguishes T. antonina from most species of the genus except T. hermaphroditica , T. arabica sp. nov. and T. majinbuui sp. nov. Tetranemertes antonina , T. majinbuui sp. nov., T. arabica sp. nov., and T. hermaphroditica are widely separated geographically, and T. antonina , T. arabica sp. nov., and T. majinbuui sp. nov. are also easily differentiated by DNA barcodes (Table 5 ). Tetranemertes hermaphroditica is a simultaneous hermaphrodite, whereas T. antonina we presume to have separate sexes.

Habitat.

Quatrefages (1846) reported the species between the shells of vermetids, which form a sort of belt around the rocks (presumably, intertidally) along the coast of Sicily. Bürger (1895) reported it as “infrequent” from subtidal depths of 70-100 m at shoals in the Gulf of Naples (Secca di Benda Palumma, Secca di Chiaia), and at the Blue Grotto of Capri. Specimens used in this study were collected from coralline red algae and Ulva at 25 m depth in the western Mediterranean Sea at Alborán Island, Spain.

Geographic distribution.

Mediterranean Sea (Banyuls, Trieste, Sicily, Gulf of Naples, Alborán Island, Almería, Strait of Gibraltar).

Etymology.

Unknown, but appears to be a derivative of a person’s name.

Notes.

The original description ( Quatrefages 1846) is very brief. While Quatrefages (1846) did not observe the stylets, noting that the proboscis is unarmed ("proboscis inerme"), Bürger’s much more detailed redescription (1895) includes an illustration of the stylet region of the proboscis, depicting a cylindrical basis that is rounded posteriorly (Fig. 2B ). It is not known whether there is variation in the shape of the basis between individuals of this species to range from rounded to forked, as we have observed among specimens of most of the newly described species. Quatrefages may have missed the stylets because Tetranemertes species have an unusually short anterior proboscis, with stylets often found within millimeters of cerebral ganglia. This proximity of proboscis armature to the brain often makes it difficult to obtain stylet preparations. Stylets of the recently collected specimens have not been examined. Photographs of recently collected live specimens identified as T. antonina and their occurrence records can be found in Herrera-Bachiller et al. (2015) and Herrera-Bachiller (2016). Unfortunately, stylet armature was not observed in the recently collected specimens.

Figures

Figure 2. Tetranemertes antonina A external appearance of T. antonina, after Buerger (1895) B central stylet of T. antonina after Buerger (1895). Tetranemertes antonina neotype (specimen: TR 3 - DR 23, Museum ID: MNCN 5.02 / 28) C external appearance of living specimen and D head in transmitted light showing distribution and number of ocelli. Abbreviations: ae - anterior end, cg - cerebral ganglion, co - cerebral organ. Scale bars: 4 mm (C); 0.75 mm (D).