Diploexochus echinatus Brandt, 1833

B, Giovanna Monticelli Cardoso, B, Rafaela Bastos-Pereira & B, Rodrigo Lopes Ferreira, 2023, Cave-dwellers Diploexochus (Isopoda, Armadillidae): new species and new records of the genus from Brazil, Nauplius (e 2023008) 31, pp. 1-15 : 2

Diploexochus echinatus Brandt, 1833

( Figs. 1 , 2 )

Diploexochus echinatus Brandt, 1833: 192 , pl. IV, figs. 20, 21;H. Milne-Edwards, 1840:180; Budde-Lund, 1909: 54; Richardson, 1912: 479; Arcangeli, 1934: 92,1957:101; Van Name, 1936: 398, figs. 241–243; Lemos de Castro, 1967: 322; Souza-Kury, 1998: 6532; Leistikow and Wägele,1999: 44; Schmalfuss, 2003: 90; Campos-Filho et al., 2017: 22, figs. 98–122; Campos-Filho et al., 2018: 27.

Armadillo echinatus — Budde-Lund, 1879: 7; Budde-Lund, 1885: 26; Budde-Lund, 1904: 104, pl. IX figs. 35–37.

Cubaris echinatus — Pearse, 1917: 3.

Cubaris gaigei — Pearse, 1917: 2, fig. 1; Van Name, 1925: 467.

Material examined. 2 males ( ISLA 77541), Brazil , Pará State , municipality of Rurópolis, Lucas cave (-4.139791º -55.071947º), 09 October 2020, R. L. Ferreira coll.

Previous records. French Guiana, Guyana, Trinidad ( Schmalfuss, 2003, Campos-Filho et al., 2017), and Brazil, Pará State: Acará and Belém ( Ilha do Marajó) ( Lemos de Castro, 1967), and Caxiuanã (Floresta Nacional Caxiuanã) ( Campos-Filho et al., 2017).

Habitat and ecological remarks. Two specimens of D. echinatus ( Fig. 1 ) were found in a sandstone cave (Lucas cave – Fig. 2 ) located in the municipality of Rurópolis, Pará State, northern Brazil. Paleozoic rocks covered by a dense Amazon ombrophilous rainforest represent the regional geology. The area is located in the hot tropical climate domain with annual dry period of 2 to 3 months. The annual average temperatures are above 20 ºC and the annual precipitation is around 1,754 mm ( Tereso et al., 1975). Lucas cave presents a single entrance ( Fig. 2A ) leading to the main cave conduit ( Fig. 2B, C ), which presents 365 m of horizontal projection. The cave does not present any drainage, although the atmosphere is moist due to the external forest and climate. A big bat colony inhabits the cave, producing massive amounts of guano, which covers a considerable portion of the floor. Both specimens of D. echinatus were found in a region close to the entrance, though already aphotic, around 25 m from the entrance on a pile of stones made by ancient inhabitants of the region (unknown reason) ( Fig. 2D ). These organisms are quite sensitive, curling up at the slightest touch, like other armadillids ( Fig. 2E ). Even though the cave was meticulously inspected looking for invertebrates, only these two specimens of Diploexochus were found. In addition, other caves sampled in the region did not reveal the presence of this species. It is important to mention that this represents the first record of this species from cave environments.

Figures

Figure 1. Diploexochus echinatus, female. A, Habitus, lateral view; B, epimera of pereonites 1-7, ventral view; C, cephalon and pereonite 1, dorsal view; D, pereonite 7, pleonites and telson, dorsal view. Scale bars: 1 mm.

Figure 2.Lucas cave, Rurópolis, Pará State, Brazil. A, Surrounding area; B, main cave conduit; C, cave conduit; D, live specimen of Diploexochus echinatus in lateral view; E, live specimen of Diploexochus echinatus showing the ability to roll into a ball.