Ctenorillo iuiuensis Cardoso & M & Bento & Ferreira 2024, n. sp.
Creators: name: Cardoso, Giovanna Monticelli
name: M, Diego de
name: Bento, edeiros
name: Ferreira, Rodrigo Lopes
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Armadillidae
Ctenorillo
Ctenorillo iuiuensis

description: Ctenorillo iuiuensis Cardoso & Ferreira, n. sp.
(Figs 21-23; 27I)
urn:lsid:zoobank.org:act: 0E0AFF4F-6924-438E-82A7-970FF1D1FD76
TYPE MATERIAL. — Holotype. Brazil • 1♂ (4 mm, parts in slide), Bahia state, Iuiu municipality, Lapa do Matias cave; 14°28’46”S, 43°36’50”W; R. L. Ferreira leg., 22.VII.2022; ISLA 96802.
Paratypes. Brazil • 2 ♀; same data as holotype; ISLA 96803.
ETYMOLOGY. — The new species name “ iuiuensis ” refers to the municipality where the species inhabits.
DIAGNOSIS. — Dorsum covered with conical tubercles three rows on cephalon (2, 2, 2); three rows on pereonite 1 (4, 4, 11); two rows on pereonites 2-6 (6+ 7) and on pereonite 7 (6 + 5); and two paramedian tubercles on pleonites 3-5 and on telson. Pleopod 1 exopod with round distal portion, outer margin straight; endopod with distal portion slightly bent outward, five times longer than exopod.
DISTRIBUTION. — Serra do Iuiu mountain range, Iuiu municipality, Bahia state.
DESCRIPTION
Maximum size: ♂ and ♀, 4 mm. Color pale (Fig. 27I). Dorsum covered with conical tubercles (Fig. 21A, B): cephalon with three rows (2, 2, and 2 from front to back of vertex); pereonite 1 with 19 in three rows (4, 4 and 11); pereonites 2-6 with 13 (6+7); pereonite 7 with 11 (6+ 5); pleonites 3-5 and telson with two paramedian tubercles. Cephalon with frontal shield protruding above vertex; eye consisting of 11 ommatidia (Fig. 21C, D). Pereonite 1 with posterior margin sinuous at sides; inner lobe of schisma rounded, extending beyond posterior margin of outer lobe; pereonite 2 with triangular ventral tooth reaching posterior margin epimera (Fig. 21A). Pereonites 2-7 (Fig. 21A) with wide quadrangular epimera slightly bent outwards. Telson (Fig. 21E) hourglass-shaped, proximal portion broader than distal portion. Antennula (Fig. 21F) of three articles, second article much shorter than first and third, third article with seven apical aesthetascs. Antenna (Fig. 21G) short and stout, flagellum shorter than fifth article of peduncle; second article of flagellum about three times as long as first. Buccal pieces as C. pelado Cardoso & Ferreira, n. sp. (Fig. 21 H-L). All pleopod exopods with monospiracular covered lungs. Uropod (Fig. 22A) protopod flattened, enlarged on basal portion; exopod very short, inserted dorsally very close to medial margin of protopod.
Male
Pereopods without particular modifications (Fig. 22B, C). Pleopod 1 exopod (Fig. 22D) wider than long, round distal portion, outer margin straight; endopod five times longer than exopod, distal portion slightly bent outward. Pleopod 2 endopod longer than exopod (Fig. 22E). Pleopods 3-5 exopods as in Figure 22 F-H.
HABITAT
The Lapa do Matias cave, located in the Iuiú region, is the only place where specimens of C. iuiuensis Cardoso & Ferreira, n. sp. have been found, despite the extensive sampling of multiple caves in the region. The Iuiú region (northeastern Brazil) presents a significant karst area, known for its numerous caves and the occurrence of dozens of endemic species restricted to caves (Cardoso et al. 2021). This limestone formation is part of the Bambuí Group, the largest carbonate formation in South America. The landscape is situated within the Caatinga domain, with a seasonally dry tropical forest mostly found in the limestone outcrops due to past intensive land use. As per the Köppen-Geiger classification system, the climate in the area is semi-arid tropical (Bsh), with an annual precipitation of 788 mm and an average temperature of 24°C. The rainy season is from November to February while the dry season lasts from March to October.
The Lapa do Matias cave is located at the top of the outcrop at Serra do Iuiú, in a quite anthropized region (Fig. 23A). The cave is in a heavily human-impacted area with pastures and exposed soil, which increases erosion. Despite its small single entrance (Fig. 23B), the cave is voluminous and has two main conduits (Fig. 23C, D). A thorough search was carried out but only three specimens of C. iuiuensis Cardoso & Ferreira, n. sp. were found under limestone blocks in aphotic areas (Fig. 23E). It is worth noting that C. iuiuensis Cardoso & Ferreira, n. sp. displays some troglomorphic traits, including a lack of pigmentation in both the body integument and eyes. As this condition was observed in all collected specimens, and none of them appeared to have a soft exoskeleton (teneral aspect), it is likely that this species is troglobitic. However, as no samplings were conducted outside caves in the area, future research is needed to confirm or refute this diagnosis.
The Iuiú karst area has been facing severe threats, particularly due to changes in the surrounding environments, which have intensified over the last few decades. According to Cardoso et al. (2022), the land cover and land use practices surrounding the caves in this region have significantly influenced the subterranean environments, affecting both microhabitat features and terrestrial invertebrate communities. The authors have demonstrated that deforested areas have had adverse effects on subterranean invertebrate richness, mainly by altering the fauna composition and reducing subterranean microhabitat diversity. Additionally, this region is home to several endemic cave species (Ratton et al. 2012; Souza et al. 2015; Hoch & Ferreira 2016; Souza & Ferreira 2018; Cardoso et al. 2020), making it imperative for Brazilian environmental agencies to take urgent action to protect these caves in this important Brazilian karst area.
REMARK Ctenorillo iuiuensis Cardoso & Ferreira, n. sp. differs from the Brazilian species by the presence of two paramedian tubercles on pleonites 3-5 and on telson.
description: Published as part of Cardoso, Giovanna Monticelli, M, Diego de, Bento, edeiros & Ferreira, Rodrigo Lopes, 2024, Unveiling a hidden diversity: descriptions of nine new species of Ctenorillo Verhoeff, 1942 (Isopoda, Armadillidae) discovered in Brazilian caves and their importance for conservation, pp. 95-132 in Zoosystema 46 (5) on pages 121-124, DOI: 10.5252/zoosystema2024v46a5, http://zenodo.org/record/10803267