Diploexochus carrapicho Campos-Filho, López-Orozco & Taiti, 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 : 563-567

Diploexochus carrapicho Campos-Filho, López-Orozco & Taiti , n. sp.

( Figs 24-26 ; 30B )

urn:lsid:zoobank.org:act:46E43019-9E9D-44DC-A333-4955024EF591

TYPE MATERIAL.— Holotype. Brazil • ♂ (parts in micropreparations); Gruta Alex 1 cave, Bodoquena, Assentamento Campina , state of Mato Grosso do Sul; 20°36’19”S, 56°42’36”W; 356 m a.s.l.; 15.V.2011; S. C. Escarpinati leg.; LES 28000 .

Paratypes. Brazil • 2♀ (one with parts in micropreparations); same data as holotype; LES 28001 .

ETYMOLOGY. — The new species is named after the seeds of Bidens alba , known as Picão-preto in Brazil, or carrapicho. The name carrapicho refers to the spine-shaped form of the seeds of this plant conferring high adherence to animal furs or human clothes. During conglobation, the new species resembles the shape of this seed.

DESCRIPTION

Maximum body length: ♂ 4 mm, ♀ 6 mm. Color faint due to long preservation in ethanol. Body ( Fig. 24A, B ) strongly convex, bearing elongate and spine-shaped tubercles, arranged as follows: vertex of cephalon with eight tubercles in two rows; pereonite 1 with 14 tubercles in three rows; pereonites 2-7 with 12 tubercles in two rows; pleonites 3-5 and telson with two paramedian tubercles each ( Fig. 24A, B, G, H ). Dorsal surface with semi-circular scale-setae ( Fig. 24C ). Noduli laterales short, inserted at base of second tubercles near posterior margins ( Fig 24A, B ). Cephalon ( Fig. 24B , E-G) with frontal shield prominent, distinctly protruding above vertex; eyes with 10-12 ommatidia.Pereonites 1-7 epimera ( Fig. 24A, D ) strongly concave and directed outwards; pereonite 1 epimera with rounded lateral margin grooved for all its length, inner lobe of schisma rounded, slightly extending beyond posterior margin of outer lobe; pereonite 2-7 epimera ( Fig. 24A ) triangular and elongated; pereonite 2 epimera ventrally with narrowly rounded lobes directed outwards ( Fig. 24A, D ); pereonite 3 epimera ventrally with broad triangular lobes directed outwards ( Fig. 24D ); pereonite 4-7 epimera with triangular lobes gradually increasing and directed backwards ( Fig. 24D ). Pleonite 3-5 epimera ( Fig. 24H, I ) well-developed, triangular, directed outwards; telson ( Fig. 24H ) with dorsum slightly depressed, distal margin slightly concave. Antennula ( Fig. 25A ) proximal article longest, distal article bearing about six aesthetascs inserted apically and subapically. Antenna ( Fig. 25B ) short, not surpassing posterior margin of pereonite 1 when extended backwards; flagellum distal article more than twice as long as first and bearing two lateral aesthetascs. Mandibles ( Fig. 25C, D ) with molar penicil semi-dichotomized. Maxillula ( Fig. 25E ) inner endite bearing two penicils, distal margin rounded; outer endite of 4+6 teeth. Maxilla ( Fig. 25F ) inner lobe covered with thick setae; outer lobe three times as wide as inner lobe covered with thin setae. Maxilliped ( Fig. 25G ) basis rectangular bearing sparse scale-setae; proximal article of palp with two distinct setae; endite subrectangular, medial seta surpassing distal margin. Pereopods 1-7 with sparse setae along sternal margin; dactylus of two claws, ungual and dactylar setae simple, not surpassing outer claw. Uropod ( Fig. 26A, B ) protopod with distal part triangular, elongated, medial margin concave; endopod bearing dense fringe of setae and glandular pores on inner margin; exopod short inserted dorsally on distinct lobe near medial margin.

Male

Pereopod 7 ( Fig. 26C ) without sexual dimorphism. Pleopod 1 ( Fig. 26D ) exopod subtriangular, twice as wide as long, outer portion narrow, medial portion rounded bearing five small setae; endopod three times as long as exopod. Pleopod 2 ( Fig. 26E ) exopod triangular, outer margin concave bearing four setae; endopod flagelliform, longer than exopod. Pleopod 3 and 4 exopods as in Figure 26F, G , respectively. Pleopod 5 exopod ( Fig. 26H ) rhomboid, distal margin almost straight bearing many setae.

REMARKS

The genus Diploexochus was erected to allocate Armadillo echinatus from Brazil ( Brandt 1833; Lemos de Castro 1967). Several Armadillidae species belonging to other genera were incorrectly assigned to Diploexochus (see Schmalfuss 2003 for an overview).To date, the genus comprises three species exclusively distributed in South America, D. echinatus , D. obscurus Cardoso, Bastos-Pereira & Ferreira, 2023 , and D. spinatus Cardoso, Bastos-Pereira & Ferreira, 2023 ( Campos-Filho et al. 2017; Cardoso et al. 2023).

Among the diagnostic characteristics proposed here, the shape and direction of the pereonites 1-7 and pleonites 3-5 epimera, pereonite 1 epimera with large schisma on posterior corners and strongly grooved outer margin, shape of the frontal shield of the cephalon, and tuberculated or spiny dorsum, are the most distinctive characters of the genus. Regarding the last character, also other members of the family have well-developed dorsal tubercles, e.g. Parakermania Vandel, 1973 , Calmanesia Collinge, 1922 , Laureola Barnard, 1960 , Pseudolaureola Kwon, Ferrara & Taiti, 1992 , and some species of Venezillo Verhoeff, 1928 (see Collinge 1922; Van Name 1936; Barnard 1958, 1960; Mulaik 1960; Taiti & Ferrara 1979; Kwon et al. 1992; Kwon & Taiti 1993). As in other tuberculated genera of Armadillidae , the best taxonomic characteristic to distinguish the species within a genus is the number and arrangement of the dorsal tubercles on the cephalon, pereon, and pleon (see also Campos-Filho et al. 2014; Taiti 2018).

Diploexochus carrapicho Campos-Filho, López-Orozco & Taiti , n. sp. can be distinguished from the congeneric species in having the dorsal surface covered with spiny shaped tubercles and in the number and arrangement of the dorsal tubercles (see Campos-Filho et al. 2017; Cardoso et al. 2023). Moreover, it differs in having pereonite 2 epimera with ventral lobe directed outwards (vs downwards in D. echinatus and D. spinatus ), telson with distal margin slightly concave (vs distinctly concave in D. echinatus ; slightly convex in D. obscurus ; straight in D. spinatus ), mandibles with molar penicil semi-dichotomized (vs simple in all other species), and uropod protopod with distal part triangular (vs subrectangular in all other species).

The spiny dorsal surface is an adaptation against predators ( Schmalfuss 1984). The specimens of D. carrapicho Campos-Filho, López-Orozco & Taiti , n. sp. were collected in the Serra da Bodoquena karst region, in the Pantanal wetland region ( Sallun Filho & Karmann 2007). This species is considered to be a troglophile, and probably inhabits caves to exploit their resources and for favourable micro-habitat conditions ( Fernandes et al. 2016, 2019).

Figures

FIG. 24. — Diploexochus carrapicho Campos-Filho, López-Orozco & Taiti, n. sp., female paratype LES 28001: A, dorsal habitus; B, lateral habitus; C, scale-seta; D, pereonite 1-7 epimera, ventral view; E, cephalon and pereonites 1-3, frontal view; F, cephalon and pereonite 1, back view; G, cephalon, dorsal view; H, pereonite 7, pleon, telson, and uropods, dorsal view; I, pleonites 4 and 5, telson and uropods, ventral view. Scale bar: A, 1 mm.

FIG. 25. — Diploexochus carrapicho Campos-Filho,López-Orozco & Taiti,n. sp., female paratype LES 28001: A, antennula; B, antenna; C, left mandible; D, right mandible; E, maxillula; F, maxilla; G, maxilliped.

FIG. 26. — Diploexochus carrapicho Campos-Filho, López-Orozco & Taiti, n. sp.: A, B, female paratype LES 28001: uropod frontal view (A); uropod, ventral view (B), C-H, male holotype, LES 28000: pereopod 7 (C); pleopod 1 (D); pleopod 2 (E); pleopod 3 exopod (F); pleopod 4 exopod (G); pleopod 5 exopod (H).

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.