Chaimowiczia uai, Cardoso 1 & Bastos-Pereira 1 & Souza 2 & Ferreira 1, 2021

Cardoso 1, Giovanna Monticelli, Bastos-Pereira 1, Rafaela, Souza 2, Leila Aparecida & Ferreira 1, Rodrigo L., 2021, Chaimowiczia: a new Iuiuniscinae genus from Brazil (Oniscidea, Synocheta, Styloniscidae) with the description of two new troglobitic species, Subterranean Biology 39, pp. 45-62 : 45

Chaimowiczia uai sp. nov. Figs 6 , 7 , 8 , 9

Material examined.

Holotype. • Male , Minas Gerais , Itacarambi , Lapa d’água do Zezé cave, -15.006745°, -44.117087°, 15 July 2019, leg. R. L. Ferreira, ISLA 78108 . Paratypes. • 2 males 1 female, same data as for holotype, ISLA 78109; • 2 male 2 females, same locality as for holotype, 12 December 2014, ISLA 78110.

Diagnosis.

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.

Description.

Maximum length: male, 8 mm. Colorless, eyes absent (Fig. 6A , 7A, B ). Dorsal surface smooth covered with scale setae with long base (reaching half the total length) and free sensory hair (Fig. 7C ). Cephalon (Fig. 7A, B ) vertex with lateral grooves; frons with distinct suprantennal line, downward in middle; round antennal lobes. Body convex; pereonite 1 postero-lateral corners well developed and projected forward, lateral margin concave; pereonite 7 slightly surpassing distal margin of pleonite 2; pleon 3-5 epimera well developed, pleonite 5 surpassing telson apex (Fig. 6A ). Telson (Fig. 6B ) with distal half subtriangular depressed, rounded apex. Antennula (Fig. 6C ) with three articles covered with setae, distal article as long as second article, with two apical aesthetascs. Antenna (Fig. 6D ) surpasses pereonite 1 when extended backwards, fifth article of peduncle shorter than flagellum; flagellum with three articles. Left mandible with two penicils (Fig. 6E ); right mandible with one penicil (Fig. 6F ). Maxillula (Fig. 6G ) outer ramus with 5 + 5 teeth, apically entire, and two thick plumose stalks; inner ramus with three penicils, two of them stout. Maxilla (Fig. 6H ) with bilobate apex, inner lobe wider than outer lobe with several setae on distal margin. Maxilliped (Fig. 6I ) basis distal portion slightly wider than basal; palp apex with tufts of setae; endite rectangular, shorter than palp, setose, apex with one rounded penicil between two strong teeth, inner tooth longer. Pereopod 1 (Fig. 8C ) antennal grooming brush composed by pectinate scales longitudinally on frontal face of propodus and carpus, dactylus with one claw; pereopod 7 basis with water conducting system scale rows. Uropod (Figs 6B , 7F ) protopod surpasses distal margin of telson, covered with pectinate scales; endopod longer than exopod, inserted at the same level.

Male. Pereopods 1, 2 and 7 (Figs 7C, E ; 8A, B ) covered with setae; merus sternal margin concave with proximal hairy tuft of setae. Genital papilla (Fig. 8C ) lanceolate. Pleopod 1 (Fig. 8C ) exopod triangular with sinuous outer margin, covered with setae; endopod shorter than exopod, basal article narrow and flagelliform distal article; protopod trapezoidal, rounded apex. Pleopod 2 (Fig. 8D ) exopod semicircular, rounded distal margin, covered with setae; endopod of two articles, basal article rectangular, shorter than exopod, distal article slender, directed backward, apex with distal projection. Pleopod 3 exopod (Fig. 8E ) trapezoidal, distal margin straight covered with setae. Pleopod 4 exopod (Fig. 8F ) rhomboid, wider than long. Pleopod 5 exopod (Fig. 8G ) ovoid, wider than long.

Etymology.

The epithet " Chaimowiczia uai " refers to the word often used by people from the state of Minas Gerais, Brazil, to express doubt, astonishment or surprise.

Ecological remarks.

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. 9A ), which is inserted in a transition between two phytogeographic domains, Cerrado (Brazilian savannah) and Caatinga (mesophytic and xeromorphic forests). Lapa D’Água do Zezé is a labyrinthine cave with one horizontal entrance (main entrance, Fig. 9C ) and at least two vertical openings. The cave presents perennial water bodies with different conditions. The first one comprises the only accessible part of the water table, a narrow passage in the base of a diaclasis (Fig. 9B ) close to one of the cave’s vertical openings (Fig. 9C ). The second area comprises a very small drainage, apparently originated by the water table overflow. Some physical and chemical parameters of the water were measured during one visit (January 2015): dissolved oxygen 3.46 mg/L, temperature 25.35 °C, pH 8.45, electrical conductivity 0.565 μS /cm, total dissolved solids 0.359 g/L. This cave also harbors two other stygobitic species and one troglobitic species: the amphipod Spelaeogammarus uai (Bastos-Pereira & Ferreira, 2017), which is easily observed in the water table (accessible through the small passage) and seldom at the small drainage; the isopod Xangoniscus santinhoi Cardoso, Bastos-Pereira, Souza & Ferreira, 2020b, which is only observed in the drainage; and the hydrometrid Spelaeometra gruta Polhemus & Ferreira, 2018. Considering the presence of the amphipod on the drainage, it is possible to infer that both water bodies are connected. Each species seems to present specific preferences. Only a few amphipods were observed in the drainage during several visits to the cave. They seem to avoid this area due to the water flow. Interestingly, specimens of C. uai sp. nov. were only found in the water table, sharing the habitat with amphipods, while no specimens were observed in the drainage (Fig. 9D, E ). As mentioned for C. tatus sp. nov., C. uai sp. nov. seems to avoid other styloniscid isopods, which are quite abundant along the drainage and very rare at the water table. This apparent avoidance may have resulted from competition between species, and this certainly deserves further investigation. Organic debris is seasonally transported to the water table (during the rainy periods) due to the proximity to the vertical entrance. Accordingly, the observed organic matter is mainly composed of vegetal debris.

Local farmers have installed a gravitational pump inside the cave in order to drag water from the cave for consumption and irrigation (Fig. 9C ) (Bastos-Pereira and Ferreira 2017). Hence, the drainage was partially altered and is disturbed by farmers, who periodically remove the sediment to allow water flow. Such intervention occurs with low frequency (once in a year, according to the farmer), and only in a few parts of the drainage. It does not seem to affect the cave communities, especially considering that a great part of the populations may be in inaccessible areas of the cave. Lastly, although the vegetation seems well preserved in the surroundings of the cave entrance, the original forests were severely altered in many areas around the outcrops and the landscape is mainly composed of pastures and crops.

Figures

Figure 6. Chaimowiczia uai sp. nov. Male A habitus, dorsal view B pleonite 5, telson and uropod, dorsal view C antennula D antenna E right mandible F left mandible G maxillula H maxilla I maxilliped. Scale bars: 1 mm (A); 0.2 mm (B, D-J); 0.1 mm (C).

Figure 7. Chaimowiczia uai sp. nov. Male A cephalon, dorsal view B cephalon, frontal view C epimeron 1, dorsal view D pereopod 1 merus, propodus, carpus and dactylus E pereopod 2 merus F Uropod. Scale bars: 1 mm (A); 100 µm (B); 400 µm (C); 500 µm (D).

Figure 8. Chaimowiczia uai sp. nov. Male A pereopod 1 B pereopod 7 C genital papilla and pleopod 1 D pleopod 2 E pleopod 3 exopod F pleopod 4 exopod G pleopod 5 exopod. Scale bars: 0.2 mm (A-H).

Figure 9. A external landscape of Lapa d'agua do Zeze cave B vertical entrance of the cave C narrow passage inside the cave with a skylight, red arrow indicates the collection site D water table where the species was collected E living specimen of Chaimowiczia uai sp. nov. with approximately 8 mm.