Gieysztoria hymanae ( Marcus, 1946 ) Luther, 1955

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 : 18

publication ID	https://doi.org/ 10.6620/ZS.2021.60-22
persistent identifier	https://treatment.plazi.org/id/7B330457-FFE2-987C-A0DC-7C9AC62ED626
treatment provided by	Felipe
scientific name	Gieysztoria hymanae ( Marcus, 1946 ) Luther, 1955
status

Treatment

Gieysztoria hymanae ( Marcus, 1946) Luther, 1955 View in CoL ( Fig. 7D–F View Fig )

Synonyms: Microdalyellia (Gieysztoria) hymanae Marcus, 1946 View in CoL .

Studied material: Seven individuals observed, four whole-mounted individuals studied alive. Afterwards, all individuals were whole mounted in Hoyer’s medium ( MZUSP PL 2237–2243).

Locality: Sites 3 (18/02/2019), associated with phytal microhabitat.

Description: Body 912.5 ± 92.9 μm (798.3– 1025.6 μm; n = 4) long ( Fig. 7D–E View Fig ). Penis stylet, 49.9 ± 8.1 μm (43.9–66.8 μm; n = 7) long, with a dorsal opened girdle and distal spines. The girdle is composed by a proximal ring, 40.7 ± 7.7 μm (30.1–50.4 μm; n = 5) width, united by bridges to a distal ring ( Fig. 7F View Fig 1–4 View Fig View Fig View Fig View Fig ). The distal ring bears spines that are composed of two different groups. The first group is composed of four hollow grouped spines, 42.7 ± 5 μm (36.8–48.7 μm; n = 5) long, with a broad triangular base. The second group bears four to six thin fine spines, 38.7 ± 3.2 μm (34.1–42.6 μm; n = 7) long, with its distal tip slightly curved inward, located interspersed with the first group of spines and are connected by its base to the distal ring ( Fig. 7F View Fig 1 View Fig , F 3 View Fig ).

Taxonomic remarks: The habitus and anatomical configuration of specimens found in the ESEC Taim are in accordance with original descriptions given by Marcus (1946), as well as those given by Brusa et al. (2008). Nevertheless, our individuals are larger than those found previously in Brazil (600–800 μm) ( Marcus 1946) and Argentina (250–290 μm) ( Brusa et al. 2008). However, when comparing the length of the penis stylet, our specimens are smaller than specimens of the original description from Brazil and the specimens from Argentina, both with 60 μm in length ( Marcus 1946; Brusa et al. 2008). The most resembling species of G. hymanae is G. evelinae , but G. hymanae differs from G. evelinae due to the latter has four robust hollow spines while G. hymanae has four hollow spines with no robustness. Another feature not observed in whole-mounted individuals was the proximal girdle, this structure may disappear when mounted in Hoyer’s medium, but it was observed in live animals.

Distribution: The species was previously recorded only in Brazil (São Paulo, river Pirajussará) ( Marcus 1946) and Argentina (Buenos Aires province, littoral of the Río de la Plata: Atalaya stream) ( Brusa et al. 2008).