Unveiling a hidden diversity: descriptions of nine new species of Ctenorillo Verhoeff, 1942 (Isopoda, Armadillidae) discovered in Brazilian caves and their importance for conservation Author Cardoso, Giovanna Monticelli Universidade Federal de Lavras (UFLA), Centro de Estudos em Biologia Subterrânea, Departamento de Biologia, programa de Pós-graduação em Ecologia Aplicada, Campus Universitário, CP 3037, 37200 - 000 Lavras, Minas Gerais (Brasil) gmcardoso. bio @ gmail. com (corresponding author) bio@gmail.com Author M, Diego de Author Bento, edeiros Author Ferreira, Rodrigo Lopes Universidade Federal de Lavras (UFLA), Centro de Estudos em Biologia Subterrânea, Departamento de Biologia, programa de Pós-graduação em Ecologia Aplicada, Campus Universitário, CP 3037, 37200 - 000 Lavras, Minas Gerais (Brasil) drops @ ufla. br drops@ufla.br text Zoosystema 2024 2024-03-05 46 5 95 132 https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2024v46a5.pdf journal article 10.5252/zoosystema2024v46a5 1638-9387 10803267 1B0779F3-FAE4-4105-8130-A26DE519721E Ctenorillo araguaia Cardoso & Ferreira , n. sp. ( Figs 5-7 ; 27C ; 28E ) urn:lsid:zoobank.org:act: 4F19B81C-879D-43EC-A3BF-0AFBB1D908EF TYPE MATERIAL . — Holotype . Brazil • 1 ♂ ( 5 mm ); Pará state; São Geraldo do Araguaia municipality; Serra das Andorinhas cave; 6°16’55”S , 48°32’34”W ; sector 4; 17-20.II.2018 ; V . F. Sperandei leg.; ISLA 96775. Paratypes . Brazil • 1 ♂ in slide; same data as holotype; ISLA96784 • 6 ♀ ; sector 1; same data as holotype; ISLA96776 • 1 ♀ ; sector 1; same data as holotype; ISLA96777 • 1 ♀ ; sector 3; same data as holotype; ISLA96778 • 3 ♂ , 8 ♀ ; sector 4; same data as holotype; ISLA96779 • 5♂ ; sector 5; same data as holotype; ISLA96780 • 3 ♂ , 5♀ sector 6; same data as holotype; ISLA96781 • 1 ♂ ; sector 7; same data as holotype; ISLA96782 • 1♂ , 3 ♀ ; same data as holotype; ISLA96783 . OTHER MATERIAL. — Brazil • 4 ♂ ; Pará state; São Geraldo do Araguaia municipality; Remanso dos Botos cave; 6°22’6”S , 48°23’38”W ; V . F. Sperandei leg.; 20.II.2018 ; ISLA 96785 . ETYMOLOGY . — The new species name is a noun in apposition that refers to the Araguaia River, a Brazilian environmental heritage: the type locality is within the hydrographic basin of the Araguaia river. The word Araguaia comes from the indigenous Amazonian language term arauay (or araguaí), which designates a type of macaw species. DIAGNOSIS . — Dorsum covered with conical tubercles and lateral ribs with three rows on cephalon (6, 2, 6); four rows on pereonite 1 (4, 7, 10, 6); two rows on pereonites 2-6 (10 + 8) and on pereonite 7 (6 + 8); one row of four tubercles on pleonites 3-5; and two paramedian tubercles on telson. Pleopod 1 exopod distal portion round, outer margin straight; endopod with distal portion slightly bent outward, slightly swollen, four times longer than exopod. FIG . 5. — Ctenorillo araguaia Cardoso & Ferreira , n. sp. paratype (male,5 mm, ISLA96784): A , habitus,lateral view; B , disposition of dorsal tubercles; C , cephalon, dorsal view; D , cephalon and pereonite 1, dorsal view; E , epimera 1-5 ventral view; F , pleonites 3-5, uropods and telson, dorsal view; G , antennula; H , antenna; I , right mandible; J , left mandible; K , maxillula; L , maxilliped. Scale bar: 0.5 mm. DISTRIBUTION .— Serra dos Martírios/Andorinhas State Park in São Geraldo do Araguaia municipality, Pará state . DESCRIPTION Maximum size: ♂ , 5 mm , ♀ , 6 mm . Color grey with lateral margins depigmented ( Fig. 27C ). Dorsum covered with conical tubercles and lateral ribs ( Figs 5A, B ; 28E ): cephalon with three rows (6, 2, and 6 from front to back of vertex); pereonite 1 with 27 in four rows (4, 7, 10 and 6); pereonites 2-6 with 18 (10 + 8); pereonite 7 with 14 (6 + 8); pleonites 3-5 with one row of four tubercles; telson with two paramedian tubercles. Dorsal cuticle ( Fig. 28E ) with short triangular scale setae; pereonites 1-7 bearing one line of noduli lateralis per side on outer surface of posterior tubercle of second line of tubercle. Cephalon with frontal shield directed upward; eye consisting of 16 ommatidia ( Fig. 5C, 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 epimeron posterior margin ( Fig. 5E ). Pereonites 2-7 ( Fig. 5A ) with wide quadrangular epimera slightly bent outwards.Telson ( Fig. 5F ) hourglass-shaped, proximal portion broader than distal portion. Antennula ( Fig. 5G ) of three articles, second article shorter than first and third, third article with six apical and one subapical aesthetascs. Antenna ( Fig. 5H ) short and stout, flagellum shorter than fifth article of peduncle; second article of flagellum about four times as long as first. Buccal pieces as C. pelado Cardoso & Ferreira , n. sp. ( Fig. 5 I-L). All pleopod exopods with monospiracular covered lungs. Uropod ( Fig. 6A ) protopod flattened, enlarged on basal portion; exopod very short, inserted dorsally close to medial margin of protopod. FIG . 6. — Ctenorillo araguaia Cardoso & Ferreira , n. sp. paratype (male, 5 mm, ISLA96784): A , uropod, B , pereopod 1; C , pereopod 7; D , pleopod 1 and genital papilla; E , pleopod 2; F , pleopod 3 exopod; G , pleopod 4 exopod; H , pleopod 5 exopod. Male Pereopods without particular modifications ( Fig. 6B, C ). Pleopod 1 exopod ( Fig. 6D ) wider than long, distal portion round, outer margin straight; endopod four times longer than exopod, distal portion slightly bent outwards, slightly swollen. Pleopod 2 endopod longer than exopod ( Fig. 6E ). Pleopods 3-5 exopods as in Figure 6 F-H. HABITAT Specimens of C. araguaia Cardoso & Ferreira , n. sp. were found in the Andorinhas cave and in Remanso dos Botos cave which are quartzite caves located in the Serra das Andorinhas Mountain Range (also known as Serra dos Martírios). The regional climate is classified, according to Köppen, as Aw5 (Tropical climate with dry season or Humid Equatorial), with annual rainfall between 1000 mm and 1500 mm and an average annual temperature of 26°C (22°-32°C). The relative humidity is high and varies from 25% to 90% with an average of 78% ( Alvares et al. 2013 ). The Andorinhas cave is 1 km long, featuring entrances on both the side cliffs covered by Amazonian Forest and the mountaintop covered by savannah vegetation ( Fig. 7A, B ). During the rainy season, an intermittent drainage flows through the cave. A large colony of insectivorous bats ( Pteronotus sp. ) inhabits some inner and isolated parts of the cave, producing a massive guano piles that cover the floor of several conduits and chambers. In upper areas of the cave conduit ( Fig. 7C ) away from the bat colony, specimens of C. araguaia Cardoso & Ferreira , n. sp. were found under rocks ( Fig. 7D ). Given the lack of bat guano in that part of the cave, it is probable that the new species feeds on plant debris carried by floods and deposited along this conduit. In contrast, the Remanso dos Botos cave is smaller ( 125 m ) and located at a lower altimetric level of the hill. The main organic deposits in this cave are guano produced by bats with distinct feeding habits, such as frugivory ( Carolia sp. ) and insectivory ( Peropteryx sp. and Natalus sp. ). Moreover, seeds transported by the bats germinate, resulting in sprouts that were also consumed by some invertebrates. Specimens of C. araguaia Cardoso & Ferreira , n. sp. were observed on the cave floor in deeper areas of the cave, as in the Andorinhas cave. FIG . 7. — Ctenorillo araguaia Cardoso & Ferreira , n. sp. : A , quartzite outcrops on the Serra das Andorinhas mountain range; B , entrance of the Andorinhas cave, where specimens are found; C , inner portion of the Andorinhas cave; D , habitus in natural condition. The caves are located in the Serra dos Martírios/Andorinhas State Park, which preserves the mountain top and cliffs. However, the surrounding landscape has been significantly impacted, particularly by deforestation for agriculture. The Andorinhas cave receives sporadic visitors, likely due to the difficult access to the cave. It is worth noting that the occurrence of C. araguaia Cardoso & Ferreira , n. sp. in these caves does not imply that the species is restricted to this habitat, especially considering the absence of any obvious troglomorphic traits. Therefore, further studies, including external samplings, are needed to better understand the distribution of the species. REMARK Ctenorillo araguaia Cardoso & Ferreira , n. sp. is similar to C. pelado Cardoso & Ferreira , n. sp. , presenting two tubercles on pereonite 1 and lateral ribs from pereonites 2 to 7, but differs in the number of tubercles on pereonite 1 (27 vs 24 in C. pelado Cardoso & Ferreira , n. sp. ), in the number of tubercles on pereonites 2 to 7 (18 tubercles on pereonites 2 to 6 and 14 on pereonite 7 vs C. pelado Cardoso & Ferreira , n. sp. with 12 tubercles on pereonites 2 to 7).