Stenostomum tuberculosum Nuttycombe and Waters, 1938

Reyes, Jhoe, Binow, Daniela, Vianna, Rogério T., Brusa, Francisco & Martins, Samantha E., 2021, Fig. 12. Majella pristis n in Periclimenaeus djiboutensis Bruce 1970, Zoological Studies 60 (22), pp. 1-33 : 8

Stenostomum tuberculosum Nuttycombe and Waters, 1938 ( Fig. 3F–G )

Synonyms: Anokkostenostomum tuberculosum ( Nuttycombe and Waters, 1938) .

Studied material: Two whole-mounted individuals studied and photographed alive.

Localities: Site 2 (30/11/2018; 15/03/2019), associated with phytal microhabitat.

Description: Live specimens whitish with three zooids. The body length is ± 438 μm long. The anterior end of the body has a small projection (tubercle) ( Fig. 3F–G ). The anterior brain lobe is metameric, while the posterior brain lobes are round-like. The anterior brain lobes are connected to the lateral ciliated pits. Oval mouth, rounded pharynx with two long lateral pharyngeal glands (?) ( Fig. 3G ). The intestine wall is lobulated.

Taxonomic remarks: This species is easily recognizable owing to the small anterior tubercle located in the frontal region of the cephalic end. Our individuals are shorter than those studied by Nuttycombe and Waters (1938) (four zooids: 800 μm), Marcus (1945b) (four zooids: 1000 μm) and Noreña et al. (2005b) (two zooids: 720 μm), but it is almost in the range of individuals found by Luther (1960) (two zooids: 480–500 μm).

Distribution: Finland ( Luther 1960), Poland ( Kolasa 1973a), Germany ( Lanfranchi and Papi 1978), USA ( Nuttycombe and Waters 1938), Suriname ( Van der Land 1970), Brazil ( Marcus 1945b), and Argentina ( Noreña et al. 2005b).

Figures

Fig. 3. Live specimens of Stenostomidae and Macrostomidae. (A–C) Stenostomum cf. pegephilum: (A) chain with two zooids, (B) schematic representation, (C) detail of the muscular pharynx. (D1–2) Stenostomum saliens: (D1) detail of the anterior region of the body and (D2) dorsal view of the habitus of a specimen. (E) Stenostomum simplex (scale bar not available). (F–G) Stenostomum tuberculosum: (F) individual with three zooids, (G) schematic representation. (H–I) Macrostomum quiritium: (H) dorsal view of a mature specimen, (I) detail of the penis stylet. (J) Macrostomum tuba, detail of the penis stylet.