Stenostomum cf. pegephilum Nuttycombe and, 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 : 7-8

Stenostomum cf. pegephilum Nuttycombe and

Waters, 1938 ( Fig. 3A–C )

Synonym: Anokkostenostomum pegephilum ( Nuttycombe and Waters, 1938) .

Studied material: A single live whole-mounted individual studied. Photographs and videos of the live animal.

Localities: Site 2 (9/10/2018), associated with phytal microhabitat

Description: Live specimens have chains with two zooids, they are whitish. The body length is 557.6 μm long and 121.5 μm wide. Blunt anterior end with two lateral small ciliated pits (29.7 μm long). Anterior and posterior brain lobes located at the anterior region: the anterior brain lobe (ahead metameric; behind, lobes laterally paired) and the posterior brain lobe (laterally paired lobed) ( Fig. 3A–B ). Longitudinal mouth with associated glands ( Fig. 3A–C ). The muscular pharynx is 99.4 μm long, it has several small pharyngeal glands at its posterior half ( Fig. 3C ). Rounded posterior end with short cilia ( Fig. 3B ).

Taxonomic remarks: General features are corroborated with descriptions given by Nuttycombe and Waters (1938), Marcus (1945b) and Noreña et al. (2005b). However, for two zooids, our specimen is smaller than those found by Nuttycombe and Waters (1938) (900 μm) and Marcus (1945b) (800 μm). Previous reports stated a transversal mouth ( Nuttycombe and Waters 1938; Marcus 1945b), but we observed a longitudinal mouth with several surrounded glands. Nuttycombe and Waters (1938) states that the pharynx seems to form a posterior separated camera, while our specimen has two differentiated pharyngeal regions.

Distribution: The species is found in Poland, Germany ( Lanfranchi and Papi 1978), USA ( Nuttycombe and Waters 1938), Italy ( Noreña et al. 2005b and references therein), Suriname ( Van der Land 1970) and Brazil ( Marcus 1945b).

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.