Iuiuniscus iuiuensis Souza, Ferreira & Senna, 2015,

Campos-Filho, Ivanklin Soares, Fernandes, Camile Sorbo, Cardoso, Giovanna Monticelli, Bichuette, Maria Elina, Aguiar, José Otávi, 2019, Two new species and new records of terrestrial isopods (Crustacea, Isopoda, Oniscidea) from Brazilian caves, Zootaxa 4564 (2), pp. 422-448: 425-427

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Iuiuniscus iuiuensis Souza, Ferreira & Senna, 2015


Iuiuniscus iuiuensis Souza, Ferreira & Senna, 2015 

Figs 3–6View FIGURE 3View FIGURE 4View FIGURE 5View FIGURE 6, 17AView FIGURE 17

Iuiuniscus iuiuensis Souza, Ferreira & Senna, 2015: 6  , figs 1–6.

Material examined. Bahia, Iuiu, Serra do Ramalho karst area: 3 males, 2 females ( LES 14353View Materials), Lapa do Baixão cave , 14°23’08”S, 43°37’35”W, 8 December 2013, leg. D.M. von Schimonsky and J.E. Gallão.GoogleMaps 

Remarks. Some characters of the species described by Souza et al. (2015) are given (see Figs 3–6View FIGURE 3View FIGURE 4View FIGURE 5View FIGURE 6):

Body outline as in Fig. 3AView FIGURE 3. Dorsal surface bearing triangular fan-shaped scale setae ( Fig. 3BView FIGURE 3) Cephalon ( Fig. 3CView FIGURE 3) with V-shaped suprantennal line. Telson ( Fig. 3DView FIGURE 3) triangular, proximal portion wider than distal portion, lateral sides concave, distal margin broadly rounded.

Antennula and antenna as in Fig. 3E and FView FIGURE 3, respectively.

Right mandible ( Fig. 4AView FIGURE 4) with one penicil and left mandible ( Fig. 4BView FIGURE 4) with two penicils.

Maxillula ( Fig. 4CView FIGURE 4) outer endite with 4+4 teeth simple at apex plus two slender setae. Maxilla ( Fig. 4DView FIGURE 4) with subequal lobes, inner lobe covered with thick setae. Maxilliped ( Fig. 4EView FIGURE 4) endite with distal margin bearing two triangular teeth and one large rounded penicil.

Pereopods 6 and 7 ( Fig. 5C, DView FIGURE 5) with water conducting system.

Uropod ( Fig. 5EView FIGURE 5) with exopod distinctly longer than endopod, both inserted at same level.

Male. Pereopods 1–5 merus with proximal lobe bearing scales and setae ( Fig. 5A, BView FIGURE 5); pereopods 6 and 7 merus with reduced lobe ( Fig. 5C, DView FIGURE 5). Genital papilla as in Fig. 6AView FIGURE 6. Pleopod 1 ( Fig. 6BView FIGURE 6) protopod very wide, outer margin cleft, proximal portion short and triangular, distal portion broad and rounded; exopod triangular; endopod of two articles, longer than exopod, second article flagelliform. Pleopod 2 ( Fig. 6CView FIGURE 6) protopod short and slender on outer portion; exopod triangular, outer margin slightly convex; endopod of two articles, about four times as long as exopod, distal portion bearing two slender lobes. Pleopod 3 exopod ( Fig. 6DView FIGURE 6) triangular, as wide as long, completely covering pleopod 2, outer margin bearing two plumose setae. Pleopod 4 exopod ( Fig. 6EView FIGURE 6) subquadrangular bearing plumose setae. Pleopod 5 exopod ( Fig. 6FView FIGURE 6) triangular, outer margin convex bearing two plumose setae, small subrectangular lobe to accommodate pleopod 2 endopod at proximal inner corner.

The troglobiotic genus Iuiuniscus  was erected by Souza et al. (2015) to allocate the new amphibious species Iuiuniscus iuiuensis  from Lapa do Baixão cave, Iuiu, state of Bahia. The authors placed the new genus in a new subfamily, Iuiuniscinae Souza, Ferreira & Senna, 2015  , based on flexible body with ability to fold, dorsal surface smooth, pereonites 1–7 epimera enlarged, pereopod 1 shorter than pereopods 2–7, pleonites with epimera very long, shape of telson, and shelter-builder behavior. As mentioned by the authors, the shelter-builder behavior is related to the molting process, reproductive patterns, reduction of water loss and predator pressure (for more details see discussion in Souza et al. 2015).

Souza et al. (2015) mentioned that Iuiuniscus iuiuensis  exhibits the male endopod 2 similar to that found in Spelunconiscus castroi Campos-Filho, Araujo & Taiti, 2014  (see Campos-Filho et al. 2014), which is confirmed herein. The examination of the material from the Lapa do Baixão cave (type locality) permitted to discover more additional morphological traits similar to those found in S. castroi  , i.e. shape of cephalon, telson with distal margin rounded, antennal flagellum multi-articulate, maxilliped endite with two triangular teeth and large rounded penicil, shape of the dactylus of the pereopods, uropod branches inserted at the same level, and shape of the male pleopods 3–5 exopods (see Campos-Filho et al. 2014). In addition, some morphological traits are similar to those found in Xangoniscus  : dorsal scale-setae double-fringed, telson with distal portion rounded, maxilliped endite with a large rounded penicil, shape of male genital papilla, and male pleopod 1 exopod and endopod (see Campos-Filho et al. 2014, 2016; Bastos-Pereira et al. 2017).

The common morphological characters between Iuiuniscus  and Spelunconiscus  , in particular the shape of male pleopod 2 endopod, which is often used as diagnostic character in the genera of Styloniscidae  , may indicate that Iuiuniscus  and Spelunconiscus  are phylogenetically closely related. In addition, the genera Iuiuniscus  , Spelunconiscus  and Xangoniscus  share a common character, i.e. the male pleopod 3 exopod enlarged and covering the pleopods 1 and 2, which probably evolved to protect the endopods of pleopods 1 and 2 with a complex reproductive apparatus (see Campos-Filho et al. 2016). Future phylogenetic studies including morphological and molecular data are necessary to clarify the relationships of these three genera and the validity of the subfamily Iuiuniscinae  .


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Iuiuniscus iuiuensis Souza, Ferreira & Senna, 2015

Campos-Filho, Ivanklin Soares, Fernandes, Camile Sorbo, Cardoso, Giovanna Monticelli, Bichuette, Maria Elina, Aguiar, José Otávi 2019

Iuiuniscus iuiuensis

Souza, L. A. & Ferreira, R. L. & Senna, A. R. 2015: 6