Diploexochus exu Campos-Filho, Sfenthourakis & Bichuette, 2023

Campos-Filho, Ivanklin Soares, Sfenthourakis, Spyros, Gallo, Jéssica Scaglione, Gallão, Jonas Eduardo, Torres, Dayana Ferreira, Chagas-Jr, Amazonas, Horta, Lília, Carpio-Díaz, Yesenia Margarita, López-Orozco, Carlos Mario, Borja-Arrieta, Ricardo, Araujo, Paula Beatriz, Taiti, Stefano & Bichuette, Maria Elina, 2023, Shedding light into Brazilian subterranean isopods (Isopoda, Oniscidea): expanding distribution data and describing new taxa, Zoosystema 45 (19), pp. 531-599 : 567-569

Diploexochus exu Campos-Filho, Sfenthourakis & Bichuette , n. sp.

( Figs 27-29 ; 30B )

urn:lsid:zoobank.org:act:5ED17375-A69D-4695-83E0-33DB9F268A83

TYPE MATERIAL. — Holotype. Brazil. • ♀; Gruna Boca da Lapa cave, Feira da Mata , state of Bahia; 13°56’46.4”S, 44°11’12”W; 544 m a.s.l.; 15.X.2020; M. E. Bichuette, D. F. Torres, J. S. Gallo, L. S. Horta & J. E. Gallão leg.; LES 28002 .

Paratypes. Brazil • 6♀ (one with parts in micropreparations); same data as holotype; LES 28003 .

ETYMOLOGY. — The new species is named after Exu, a divinity of the Candomblé Afro-Brazilian religion. In the Candomblé, Exu is the messenger of the orixás divinities, transiting between the world of humans and the gods. He is considered the owner of the paths, the crossroads, the perspectives, the past, and the future, and he is responsible for order and disorder.

DESCRIPTION

Maximum body length: 6.5 mm. Color brown with typical muscle insertion spots; cephalon, pereonite 1, pereonite 2-7 posterior portions, pleon, telson and uropods strongly pigmented. Body ( Fig. 27A ) strongly convex, bearing triangular tubercles, arranged as follows: vertex of cephalon with eight tubercles in two rows; pereonite 1 with 13 tubercles in three rows; pereonite 2 with 11 tubercles in two rows; pereonites 3 and 4 with nine tubercles in two rows; pereonites 5-7 with seven tubercles in one row; pleonites 5 and telson with two tubercles on median portion ( Fig. 27B ). Dorsal surface with semi-circular scale-setae ( Fig. 27C ). Noduli laterales short, inserted on outer part of second tubercle from lateral margins ( Fig. 27A ). Cephalon ( Fig. 27A, D, E ) with frontal shield prominent, distinctly protruding above vertex; eyes with 10 ommatidia; pereonite 1-7 epimera ( Fig. 27A , E-H) strongly concave; pereonite 1 epimera with rounded, lateral margin grooved on posterior corner for about one quarter of its length, inner lobe of schisma rounded, not extending beyond posterior margin of outer lobe; pereonite 2-7 epimera ( Fig. 27F, I, J ) triangular and elongated; pereonite 2 epimera with narrow and rounded lobe directed outwards ( Fig. 27F, J ); pereonites 3 and 4 without lobe; pereonites 5-7 with ventral sulcus ( Fig. 27F ). Pleonite 3-5 epimera ( Fig. 27K ) triangular; telson ( Fig. 27K, L ) dorsum slightly depressed, distal margin slightly convex. Antennula ( Fig. 27M ) with proximal and distal articles similar in length, distal article bearing about six aesthetascs inserted apically and subapically. Antenna ( Fig. 27N ) short, not surpassing posterior margin of pereonite 1 when extended backwards; flagellum distal article about three times as long as first, bearing two lateral aesthetascs. Mandibles ( Fig. 28A, B ) with molar penicil dichotomized. Maxillula ( Fig. 28C ) inner endite bearing two penicils, distal margin rounded; outer endite of 4+6 teeth, outer set apically entire. Maxilla ( Fig. 28D ) inner lobe covered with thick setae; outer lobe three times as wide as inner lobe covered with thin setae. Maxilliped ( Fig. 28E ) basis rectangular bearing sparse setae; proximal article of palp with two distinct setae; endite subrectangular, medial seta surpassing distal margin, ventral sulcus setose ending with short seta. Uropod ( Fig. 29A, B ) protopod enlarged on basal part, distal part subtriangular, broad, medial margin concave; endopod short bearing setae; exopod short inserted dorsally on distinct lobe near medial margin. Pereopods 1-7 ( Fig. 29C, D ) with sparse setae along sternal margin; pereopod 1 carpus with longitudinal antenna-grooming brush; dactylus of two claws, ungual and dactylar setae simple, not surpassing outer claw. Pleopod 1 exopod (not drawn) sub-circular, twice as wide as long, outer portion narrow, median portion rounded bearing five small setae. Pleopod 2 exopod ( Fig. 29E ) triangular, outer margin concave. Pleopod 3 and 4 exopods as in Figure 29F, G , respectively. Pleopod 5 exopod ( Fig. 29H ) rhomboid, distal margin almost straight bearing many setae.

REMARKS

Within Oniscidea , most of the morphological characters used in taxonomy to describe and distinguish species are those of males (e.g., Taiti & Ferrara 1980; Leistikow 1999; Campos-Filho et al. 2015a; Reboleira et al. 2015). As mentioned previously, though, conglobating representatives, especially within the Armadillidae , male characters are not always useful, e.g., in Ctenorillo , Tuberillo Schultz, 1982 , and Venezillo ( Van Name 1936; Schmalfuss & Ferrara 1983; Taiti & Gruber 2010). Thus, other characters, such as the conglobating mechanism, the presence and arrangement of dorsal tubercles (in tuberculated animals), and the shape of the lateral schisma of pereonite 1 (if present), are useful to distinguish species, even in the absence of males. Diploexochus exu Campos-Filho, Sfenthourakis & Bichuette , n. sp. easily differs in the shape and arrangement of dorsal tubercles. Moreover, it can be distinguished in having the pereonite 1 epimera with lateral groove of about one quarter of the length of the epimeron (vs all epimeron grooved in D. echinatus , D. carrapicho Campos-Filho, López-Orozco & Taiti , n. sp., and D. spinatus ; about two thirds of the epimeron lenth in D. obscurus ), telson with distal margin slightly convex (vs concave in D. echinatus ; slightly concave in D. carrapicho Campos-Filho, López-Orozco & Taiti , n. sp.; slightly convex in D. obscurus ; straight in D. spinatus ), eyes composed of about 10 ommatidia (vs about 20 in D. echinatus and D. spinatus ; 16 in D. obscurus ), mandibles with molar penicil semi-dichotomized (vs simple in all other species), and uropod protopod with distal portion subquadrangular (vs subrectangular in D. echinatus , D. obscurus , and D. spinatus ; triangular in D. carrapicho Campos-Filho, López-Orozco & Taiti , n. sp.) (see also Campos-Filho et al. 2017; Cardoso et al. 2023).

This species is considered to be a troglophile due to the absence of troglomorphic characteristics. It probably inhabits caves to exploit their resources and favourable micro-habitat conditions ( Fernandes et al. 2016, 2019).

Figures

FIG. 27. — Diploexochus exu Campos-Filho, Sfenthourakis & Bichuette, n. sp., female paratype LES 28003: A, lateral habitus; B, tubercles schem; C, scale-seta; D, cephalon, back view; E, cephalon and pereonites 1 and 2, frontal view; F, pereonite 1-7 epimera, ventral view; G, pereonite 1 epimeron, dorsal view; H, pereonite 1 epimeron, ventral view;I, pereonite 2 epimeron, dorsal view;J, pereonite 2 epimeron, ventral view; K, pereonite 7, pleon, telson and uropods,dorsal view, L, telson; M, antennula; N, antenna. Scale bar: A, 1 mm.

FIG. 28. — Diploexochus exu Campos-Filho, Sfenthourakis & Bichuette, n. sp., female paratype LES 28003: A, left mandible; B, right mandible; C, maxillula; D, maxilla; E, maxilliped.

FIG. 29. — Diploexochus exu Campos-Filho, Sfenthourakis & Bichuette, n. sp., female paratype LES 28003: A, uropod, frontal view; B, uropod; C, pereopod 1; D, pereopod 7; E, pleopod 2 exopod; F, pleopod 3 exopod; G, pleopod 4 exopod; H, pleopod 5 exopod.

FIG. 30. — Distribution map of the Armadillidae representatives: A, Cubaris murina (Brandt, 1833); B, Diploexochus carrapicho Campos-Filho, López-Orozco & Taiti, n. sp., and D. exu Campos-Filho, Sfenthourakis & Bichuette, n. sp. Abbreviations of states: BA, Bahia; GO, Goias; MG, Minas Gerais; MS, Mato Grosso do Sul; MT, Mato Grosso; SE, Sergipe; SP, Sâo Paulo; TO, Tocantins.