Benthanoides amazonicus, Cardoso & Ferreira, 2023

Cardoso, Giovanna Monticelli & Ferreira, Rodrigo Lopes, 2023, New troglobitic species of Benthana Budde-Lund, 1908 and Benthanoides Lemos de Castro, 1958 from iron-ore caves and their important record in the Amazon biome (Crustacea: Isopoda: Philosciidae), Zootaxa 5319 (4), pp. 548-562 : 553-555

Benthanoides amazonicus n. sp.

( Figures 3C , 6 and 7 )

Type material. Holotype: male (ISLA 30597), Brazil, Pará state, municipality of Parauapebas , cave N1_0118 (- 6.011570° -50.315151°), 17.vii–4.viii.2014, leg. Carste et al . Paratypes: 1 female ( ISLA 30825), 7–28.i.2015 ; 1 female ( ISLA 30824), 7–28.i.2015, same location as holotype .

Additional material: Brazil, Pará state, municipality of Parauapebas, leg. Carste et al.: Cave N 1_0052 (- 6.027133° -50.276070°): 1 female (ISLA 30753), 4.ix–6.x.2014 . Cave N1_0054 (-6.020486° -50.277299°): 1 female (ISLA 30598), 11.vi–2.vii.2014 . Cave N1_0061 (-6.029507° -50.272607°): 1 female (ISLA 30456), 24.ii– 13.iii.2015 . Cave N1_0065 (-6.018455° -50.280455°): 1 female (ISLA 30742), 4.ix–6.x.2014 . Cave N1_0088 (-6.017547° -50.284983°): 2 males (one in slide), 1 female (ISLA 30696). N1_0102 (-6.014371° -50.291041°): 1 female (ISLA 30458), 4.ix–6.x.2014 ; 1 male 1 female (ISLA 30461), 2–29.iv.2015 ; 2 females (ISLA 30472), 2–29.iv.2015 ; 1 male (ISLA 30724), 4.ix–6.x.2014 ; 2 males 1 female (ISLA 30730), 4.ix–6.x.2014 . Cave N1_0106 (-6.022007° -50.306292°): 1 male (ISLA 30804 in slide), 7–28.i.2015 ; 1 female (ISLA 30585), 11.vi–2.vii.2014 . Cave N1_0112 (-6.007904° -50.291736°): 1 female (ISLA 30438), 2–29.iv.2015 . Cave N1_0117 (-6.011362° - 50.314673°): 1 female (ISLA 30797), 7–28.i.2015 . Cave N1_0121 (-6.034508° -50.299373°): 2 females (ISLA 30471), 2–29.iv.2015 ; 3 females (ISLA 30748), 4.ix–6.x.2014 . Cave N1_0124 (-6.004271° -50.287711°): 1 female (ISLA 30807), 7–28.i.2015 . Cave N1_0125 (-6.004525° -50.287964°): 1 female (ISLA 30811), 7–28.i.2015 . Cave N1_0128 (-6.008184° -50.291799°): 2 females (ISLA 30436), 2–29.iv.2015 . Cave N1_0129 (-6.010355° - 50.291733°): 1 female (ISLA 30467), 2–29.iv.2015 . Cave N1_0177 (-6.027469° -50.297973°): 1 male (ISLA 30726 part in slide), 4.ix–6.x.2014 ; 2 males (ISLA 30741) ; 1 female (ISLA 30697) ; 1 female (ISLA 30725), 2 males 1 female (ISLA 30473), 2–29.iv.2015 . Cave N1_0178 (-6.040079° -50.291387°): 1 female (ISLA 30457), 24.ii–13.iii.2015 . Cave N1_0191 (-6.046511° -50.277978°): 2 females (ISLA 30442), 2–29.iv.2015 . Cave N1_0198 (-6.046546° -50.290927°): 1 female (ISLA 30747), 4.ix–6.x.2014 . Cave N1_0207 (-6.057847° -50.286629°): 2 males 3 females (ISLA 30684), 4.ix–6.x.2014 . Cave N1_0229 (-6.022811° -50.312824°): 1 male 1 female (ISLA 30459), 2–29.iv.2015 ; 1 male (ISLA 30740), 4.ix–6.x.2014 . Cave N1_0231 (-6.020842° -50.272916°): 2 males 3 females (ISLA 30808), 3–17.xii.2014 ; 2 females (ISLA 30595), 11.vi–2.vii.2014 . Cave N1_0232 (-6.020969° - 50.273115°): 1 male (ISLA 30815), 3–17.xii.2014 . Cave N1_0238 (-6.021051° -50.273964°): 1 juv (ISLA 30690), 11.vi–2.vii.2014 ; 1 female (ISLA 30602), 11.vi–2.vii.2014 ; 1 female (ISLA 30592), 11.vi–2.vii.2014 . Cave N1_ 0248 (-6.068783° -50.272464°): 3 females (ISLA 30447), 2–29.iv.2015 .

Diagnosis. Eyes with seven ommatidia; antennula with 13+2 aesthetascs; male pleopod 1 exopod elongated, longer than wide, distal part prominent acute, uropod exopod twice longer than endopod.

Description. Maximum body length: male 4 mm, female 5 mm. Colorless. Body convex, outline as in Fig. 6A . Dorsal surface smooth bearing long triangular scale-setae ( Fig. 6B ); noduli laterales long, one line per side with d/c coordinates reaching maximum on pereonite 4; b/c coordinates gradually decreasing ( Fig. 6C, D ). Cephalon ( Fig. 6E ) with suprantennal line bent downwards in middle, no frontal line and lateral lobes; eyes composed of seven small ommatidia arranged in two rows. Pereonites 5–7 with postero-lateral corners gradually more acute; pleon narrower than pereon ( Fig. 6A ). Telson ( Fig. 6F ) triangular, lateral sides straight, apex acute. Antennula ( Fig. 6G ) of three articles, distal article longest bearing 13 lateral aesthetascs in four rows, plus apical pair. Antenna ( Fig. 6H ) long, reaching pereonite 3 when extended backwards, distal article of peduncle longer than flagellum; flagellum of three articles, first and second articles subequal in length, distal article longest, second article with one aesthetasc, third article with two aesthetascs; apical organ short. Mandibles with molar penicil of 8 branches, left mandible ( Fig. 6I ) with 2+1 penicils, and right mandible ( Fig. 6J ) with 1+1 penicils. Maxillula (Fig. K) inner endite with two penicils; outer endite with 4+5 teeth (5 pectinate). Maxilla ( Fig. 6L ) outer as wide as inner lobe, covered with thick setae; outer lobe with sinuous distal margin, covered with thin setae. Maxilliped ( Fig. 6M ) with rectangular basis; endite rectangular, medial seta surpassing distal margin, two hooks on distal margin, dorsal face with longitudinal ridge bearing dense setae; proximal article of palp with two setae, one longer. Pereopods slender; carpus 1 with transverse antennal grooming brush, distal seta with hand-like apex; dactylus inner claw shorter than outer claw, dactylar and ungual setae simple, not surpassing outer claw. Uropod ( Fig. 6F ) protopod subquadrangular, protopod and exopod grooved on outer margin bearing glandular pores, exopod 2 times longer than endopod, endopod inserted proximally.

Male. Pereopods 1–3 ( Fig. 7A ) merus and carpus with brushes of setae on sternal margin. Pereopod 7 ( Fig. 7B ) ischium lateral margin grooved; merus with proximal lobe and thick setae near sternal margin. Genital papilla ( Fig. 7C ) with triangular ventral shield. Pleopod 1 ( Fig. 7C ) exopod elongated, longer than wide, distal part prominent acute, straight apex; endopod longer than exopod, stout and straight, distal portion tapering with line of short setae. Pleopod 2 ( Fig. 7D ) exopod triangular, outer margin concave with two setae; endopod slender, slightly longer than exopod. Pleopods 3 and 4 exopods as in Fig. 7E, F , respectively. Pleopod 5 exopod ( Fig. 7G ) triangular, outer margin sinuous with four setae and transverse plumose fringe.

Etymology. The name of the species refers to the locality of collection of the species, Amazon rainforest.

Morphological remarks. Considering the absence of the autapomorphic state of the male pleopod 1 exopod with a lateral dentiform protrusion of Benthana ( Leistikow 2001) , this new species was placed in Benthanoides , a close related taxon which lacks this protrusion. Unfortunately, the descriptions of Benthanoides species lack important taxonomic information regarding the position of noduli laterales, the number and disposition of aesthetascs on antennula, and the shape of male pleopods ( Jackson 1926, Van Name 1936, Gruner 1955). However, Benthanoides amazonicus n. sp. presents the shape of male pleopod 1 exopod similar to the pattern for the genus, without a dentiform protrusion.

Ecological remarks. Specimens of Benthanoides amazonicus n. sp. were found in 25 caves in the N1 plateau (Serra Norte complex). Since the specimens were collected by consulting company, unfortunately, no data were provided about the caves or the surrounding region. However, two aspects deserve to be highlighted: the first is the presence of large iron ore quarries in the N1 region, which certainly represents a great risk for this species, especially concerning habitat loss and potential disconnection between populations (or sub-populations) that can become isolated and thus even more threatened. The second refers to the very small size of the specimens (about 4 mm), which demonstrates the access of these organisms to the canga’s canaliculi. Accordingly, such canaliculi may not only allow the dispersion of individuals between caves but also eventually comprise a significant portion of their habitat. In this perspective, the existing quarries in the region (in full expansion) certainly have the potential to fragment the populations of this species, increasing its risks of extinction.

Figures

FIGURE 3. A, Benthana iporangensis; B, Benthana alba n. sp.; C, Benthanoides amazonicus n. sp.; D, Benthanoides tarzan n. sp. Scale bar: 1 mm.

FIGURE 6. Benthanoides amazonicus n. sp., male paratype (ISLA 30726).A, habitus, dorsal view; B, epimeron 1 with nodulus lateralis and tricorn scale-setae; C, noduli laterales b/c coordinates; D, noduli laterales d/c coordinates; E, cephalon, frontal view; F, pleonite 5, pleotelson and uropod; G, antennula; H, antenna, I, left mandible; J, right mandible; K, maxillula; L, maxilla; M, maxilliped. Scale bar: 1 mm.

FIGURE 7. Benthanoides amazonicus n. sp., male paratype (ISLA 30726).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.