Strongylostoma elongatum Hofsten, 1907

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 : 16

Strongylostoma elongatum Hofsten, 1907 ( Fig. 6C–E )

Studied material: Eight individuals studied alive in whole-mounted preparations, one of them fixed in AFA ( MZUSP PL 2262).

Localities: Site 1 (19/09/2018), Site 2 (15/03/2019) and Site 3 (18/02/2019), associated with benthal and phytal microhabitats

Description: Body, 1.3 mm long and 0.2 mm wide, fusiform, orange brownish. One pair of eyespots at the anterior region of the body, with rod tracks between them ( Fig. 6C, E ). Rosulatus pharynx situated in the first half of the body, anterior to the common genital pore. The male reproductive system has the ejaculatory duct with distal spines ( Fig. 6D–E ).

Taxonomic remarks: A notorious feature that differentiates S. elongatum from other species of the genus Strongylostoma is the ejaculatory duct with distal spines. Hence, species with spines along all the ejaculatory duct ( S. cirratum Beklemischew, 1922 , S. dicorymbum Marcus, 1946 and S. radiatum Müller, 1774 ) and lacking them ( S. simplex Meixner, 1915 and S. devleeschouweri Van Steenkiste et al. 2011b ) are easily discriminated. Also, our specimens, when compared with S. coecum ( Sekera 1906) Sekera 1912 (do not present eyes) and S. gonocephalum (see Graff 1913) (with oval spots beside and behind of the eyes) are easily differentiated. In conclusion, owing to the notable features observed, our specimens are S. elongatum . This is the first record for Brazil and the Neotropical region.

Distribution: Widespread throughout the Palearctic and Nearctic region (see Van Steenkiste et al. 2011b).

Figures

Fig. 6. Live specimens of Typhloplanidae. (A) Mesostoma ehrenbergii, dorsal view of a mature individual observed in dark field. (B) Brothromesostoma evelinae, dorsal view. (C–E) Strongylostoma elongatum: (C) dorsal view of a mature specimen, (D) detail of the male copulatory organ (scale bar not available), (E) schematic representation of the habitus.