Research Article |
Corresponding author: Giovanna Monticelli Cardoso ( gmcardoso.bio@gmail.com ) Academic editor: Stefano Taiti
© 2021 Giovanna Monticelli Cardoso, Rafaela Bastos-Pereira, Leila Aparecida Souza, Rodrigo L. Ferreira.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Cardoso GM, Bastos-Pereira R, Souza LA, Ferreira RL (2021) Chaimowiczia: a new Iuiuniscinae genus from Brazil (Oniscidea, Synocheta, Styloniscidae) with the description of two new troglobitic species. Subterranean Biology 39: 45-62. https://doi.org/10.3897/subtbiol.39.65305
|
A new genus of Styloniscidae, Chaimowiczia gen. nov., is described with two new species: Chaimowiczia tatus sp. nov. from Gruta do Padre cave (Santana, Bahia) and Chaimowiczia uai sp. nov. from Lapa d’água do Zezé cave (Itacarambi, Minas Gerais). The new genus and species were allocated into the subfamily Iuiuniscinae, hitherto monotypic, by the pronounced rectangular-shaped lateral pereonites epimera, dorsal surface smooth, body outline continuous without a gap between pereon and pleon, and pleonites 3 to 5 developed forming tips. The two species of Chaimowiczia gen. nov. differ in the shape of cephalon antennal lobes, pereonite 1 epimera, pleonite 5 posterior margin and uropod exopod and endopod proportion.
amphibious isopods, Cave fauna, Isopoda, Neotropics, São Francisco basin
The family Styloniscidae is currently composed of 16 genera (Boyko et al. 2020), grouped into four subfamilies: Styloniscinae Vandel, 1952, Notoniscinae Vandel, 1952, Kuscheloniscinae Strouhal, 1961 and Iuiuniscinae Souza, Ferreira & Senna, 2015. Styloniscinae are the most representative, including 12 genera, some with pantropical distribution, while others are endemic to a single location (
Most Styloniscidae species known in Brazil inhabit subterranean ecosystems, except for Pectenoniscus angulatus Andersson, 1960 and Styloniscus spinosus (Patience, 1907) (
We present a new genus of Styloniscidae allocated into the subfamily Iuiuniscinae, with the description of two new species found in Brazilian caves. In addition to the taxonomic descriptions, this paper provides ecological and conservation information related to the new species and the subterranean ecosystems where they were found.
The specimens were manually collected and fixed in 70% ethanol. They were measured and photographed with a ZEISS Axio ZoomV16 stereomicroscope coupled with an Axio Cam 506 Color camera, dissected and mounted in slides using Hoyer’s medium in the Center of Studies on Subterranean Biology of the Federal University of Lavras (CEBS–UFLA, Lavras, Brazil). Drawings were made either from photographs or with the aid of a camera lucida coupled with the microscope Leica DM750. Illustrations were prepared using the software GIMP (v. 2.8) (
Chaimowiczia tatus sp. nov.
Body non-volvational. Cephalon with antennal lobes, distinct suprantennal line bent in middle, vertex with lateral grooves. Body outline continuous with pereonites epimera well developed, widely separated, pleonites 1 and 2 bridge the gap between pereon and pleon, pleonites 3–5 with epimera well developed. Telson with subtriangular distal half depressed with rounded apex. Antennula of three articles covered with setae, distal article with two apical aesthetascs. Antenna with flagellum of three distinct articles covered with setae. Mandibles pars molaris large and projected. Maxillula outer ramus with entire teeth and two long and thick setose stalks; inner ramus with three penicils at apex. Maxilla inner lobe wider than outer lobe. Maxilliped basis trapezoidal; endite bearing one penicil between two strong teeth. Pereopods with unbranched dactylar setae. Genital papilla lanceolate. Male pleopod 1 exopod and endopod subequal in length, endopod two-jointed, with flagelliform distal article. Male pleopod 2 endopod with two thickset articles, distal one tapering apically.
The genus is named after Dr Flavio Chaimowicz, a physician who provided important contributions for the Brazilian speleology. Gender feminine.
The diagnosis of Styloniscinae, Notoniscinae and Kuscheloniscinae has been presented in old publications that unfortunately include few characters of their members (
Chaimowiczia gen. nov., as well as Iuiuniscus, occurs in the São Francisco River Basin and the caves are in the limestone plateaus of the Bambuí Group (
Holotype. • 1 Male; Bahia, Santana, Gruta do Padre cave, -13.216325°, -44.065194°, 11 July 2014, leg. R. L. Ferreira, ISLA78105. Paratypes. • 1 female, same data as for holotype, ISLA78106; • 1 male 1 female, same locality as for holotype, 18 July 2019, ISLA78107.
Chaimowiczia tatus sp. nov. is characterized by pereonite 1 epimera directed sideways; quadrangular antennal lobes; pleonites 3–5 epimera tips well developed, pleonite 5 short, not surpassing the apex of telson; and uropods endopod and exopod subequal in length.
Maximum length: male, 9 mm. Colorless, eyes absent (Figs
Male. Pereopods 1, 6 and 7 (Figs
The epithet “tatus” refers to the “Tatus II project”, an experiment of human permanency inside a cave held in 1987, conducted in Gruta do Padre cave. During the experiment, a group of speleologists stayed for 21 days inside the cave performing topographic and speleology surveys (Chaimowicz, 1987).
Gruta do Padre comprises an extensive cave with 16,400 m of horizontal projection and is currently considered the fifth longest cave in Brazil (
Holotype. • Male, Minas Gerais, Itacarambi, Lapa d’água do Zezé cave, -15.006745°, -44.117087°, 15 July 2019, leg. R. L. Ferreira, ISLA78108. Paratypes. • 2 males 1 female, same data as for holotype, ISLA78109; • 2 male 2 females, same locality as for holotype, 12 December 2014, ISLA78110.
Chaimowiczia uai sp. nov. is characterized by the concave shape of pereonites epimera, with pereonite 1 epimeron directed frontward; round antennal lobes; pleonites 3–5 epimera with tips well developed, pleonite 5 surpassing apex of telson; and uropods endopod longer than exopod.
Maximum length: male, 8 mm. Colorless, eyes absent (Fig.
Male. Pereopods 1, 2 and 7 (Figs
The epithet “uai” refers to the word often used by people from the state of Minas Gerais, Brazil, to express doubt, astonishment or surprise.
Lapa D’Água do Zezé cave is located at the border of Cavernas do Peruaçu National Park. Although most of the outcrop where the cave is inserted within the limits of the park, the cave entrance is outside the park’s limit. The external landscape is composed of a well-preserved deciduous forest on the limestone outcrop and surroundings (Fig.
Local farmers have installed a gravitational pump inside the cave in order to drag water from the cave for consumption and irrigation (Fig.
Chaimowiczia uai sp. nov. differs from C. tatus sp. nov. in having rounded antennal lobes on cephalon (vs. quadrangular in C. tatus sp. nov.), anterior portion of pereonite 1 epimera directed frontward (vs. outwards in C. tatus sp. nov.), pleonite 5 posterior margin surpassing distal margin of telson (vs. shorter than distal margin in C. tatus sp. nov.), and uropod endopod longer than exopod (vs. endopod as long as exopod in C. tatus sp. nov.).
Chaimowiczia gen. nov. was allocated into the subfamily Iuiuniscinae. Iuiuniscinae was created to include Iuiuniscus iuiuensis Souza, Ferreira & Senna, 2015, a species with unique behavior in Oniscidea: it builds semi-spherical shelters using clay. This behavior represents an evolutionary novelty that probably could support the subfamily as a clade (or support a least inclusive group in which this characteristic has arisen), even if other possible species of Iuiuniscinae, such as the new species of Chaimowiczia gen. nov. described here, do not exhibit this characteristic.
Good character interpretation is essential to achieve more robust results in phylogenetic analysis. In taxonomy, primary homology hypotheses are made when taxa are comparatively described. It is not possible to start a phylogenetic analysis without resorting to descriptive works. Improvement of descriptive works such as
An important morphological trait observed in both species of Chaimowiczia gen. nov. are the rectangular-shaped lateral projections of pereonites epimera and somewhat acute in pleonites. These projections of pereonites and pleonites may be, another synapomorphies of Iuiuniscinae, in addition to the behavioral characteristic already mentioned. These lateral projections differ from the lateral projections in Iuiuniscus, especially considering the pleonites. The presence of morphological modifications (as some sort of spines) in subterranean crustaceans is well documented, and evidences associate them to mechanical defense mechanisms preventing predation (
The here described genus raises to 17 the number of Styloniscidae living genera in the world, nine of them with occurrence in Brazil. Brazilian caves currently shelter 20 described species of Styloniscidae, while five other are found in epigean habitats (
The authors would like to thank FAPEMIG (Minas Gerais State Agency for Research and Development)/Vale S.A. for the financial support and scholarship provided to RBP and GMC; CNPq (National Council for Scientific and Technological Development) for the productivity scholarship provided to RLF (CNPq n. 308334/2018-3); the owners of the farms for the permission to access the cavities where the new species were collected, specially Euripes Pedro dos Santos (“Santinho”) in Lapa d’água do Zezé cave. We would also like to thank the team from the Center of Studies in Subterranean Biology (CEBS/UFLA) for the support in the field trips.