Circoniscus boitata, Galo & Cardoso & Ferreira, 2025

Circoniscus boitata sp. nov.

Zoobank registration: urn:lsid:zoobank.org:act:

( Figures 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 ; 6 View FIGURE 6 )

Type material. Holotype. Male (ISLA97041), Brazil, Minas Gerais state, municipality of Itacarambi, Nestor cave (-15.012456°; -44.121890°), 25/I/2015, L.M. Rabelo leg. ; Paratypes. 3 females, 1 male, same data as holotype ( ISLA 95810) ; 1 female, same data as holotype ( ISLA 97043) (SEM) ; 2 females, 1 male (ISLA97044), Brazil, Minas Gerais state, municipality of Itacarambi, Lapa d’água do Zezé cave (-15.006745°; -44.117087°), 25/I/2015; L.M Rabelo leg.

Etymology. The specific epithet is a noun in apposition. In Brazilian folklore, Boitatá (also known as the "fire serpent") is a mythical creature that protects forests and fields from those who seek to burn or destroy them. In some versions of the legend, it is described as a large, glowing serpent that transforms into a blazing log to punish wrongdoers.

Diagnosis. Circoniscus boitata sp. nov. is characterized by the absence of eyes and body pigment; schisma on pereonite 1; pereonites 2 and 3 with ventral lobes; antenna with 6 aesthetascs arranged in two sets; antennula bearing 7 aesthetascs on lateral margin arranged in three sets; male pereopod 7 ischium elongated; male pleopod 1 exopod wider than long; pleopod 5 exopod reduced; distal margin of pleotelson straight.

Description. Male holotype ( ISLA 97041). Maximum body lenght: 4.3mm. Eyes and body pigment absent. Body convex, with endoantennal conglobation capacity ( Fig. 1A View FIGURE 1 ), surfacecovered by small triangular scale-setae. Noduli laterales and glandular pores not visible ( Fig. 2F View FIGURE 2 ).

Cephalon ( Figs 1B, C View FIGURE 1 ; 2A, B View FIGURE 2 ) wider than long, frontal shield continuous with pereonite 1, frontal margin broadly rounded with concave sides, lateral lobes absent.

Pereonite 1 epimera ( Fig. 1A, D View FIGURE 1 ; 2F View FIGURE 2 ) with schisma; pereonites 2 and 3 ( Fig. 1A, D View FIGURE 1 ; 2G View FIGURE 2 ) with ventral lobes; pereonites epimera inner face ( Fig.2G View FIGURE 2 ) with continuous ridge.

Pleon ( Fig. 1E View FIGURE 1 ; 2H View FIGURE 2 ) outline continuous with pereon, epimera 3–5 well developed.

Pleotelson ( Fig. 1E View FIGURE 1 ; 2H View FIGURE 2 ) triangular, broader than long, anterior margin straight, lateral margins not following outline of pleonite 5, distal margin rounded.

Antennula ( Fig. 1F View FIGURE 1 ) with three articles, distal article approximately five times longer than second article, conical, with seven lateral aesthetascs arranged in three sets.

Antenna ( Fig. 1G View FIGURE 1 ; 2C, D View FIGURE 2 ) short and stout, not surpassing pereonite 2 when extended backwards; flagellum of two articles, distal article elongated, longer than proximal article,bearing two lateral sets of three aesthetascs each; apical organ longer than distal article of flagellum.

Mandibles ( Fig. 3A, B View FIGURE 3 ) molar penicil with 6-7 branches, left mandible with 2+1 penicils and right mandible with 1+1 penicils.

Maxilliped ( Fig. 3C View FIGURE 3 ) basis rectangular, bearing sparse thin setae; palp proximal article with one long seta, medial and distal articles with two tufts of long thin setae; endite subrectangular, medial seta short, not surpassing distal margin, distal margin covered with thin setae, without any seta on outer portion, rostral surface with one short penicil.

Maxilla ( Fig. 3D View FIGURE 3 ) inner lobe rounded, covered with thick setae, outer lobe approximately three times wider than inner lobe; covered with thin setae.

Maxillula ( Fig. 3E View FIGURE 3 ) inner endite with two apical penicils, distal margin slightly rectangular; outer endite with 6 + 6 teeth, inner set with five cleft and one simple teeth.

Pereopods (1-7) gradually increasing in size. Pereopod 1 ( Fig. 2E View FIGURE 2 ; 4A View FIGURE 4 ) covered by robust setae, mainly propodus, carpus and merus; propodus and carpus with sparse hand-like setae on distal margin, with antennal grooming brush; dactylus inner claw shorter than outer claw, ungual and dactylar setae long and simple.

Uropod ( Fig. 2H View FIGURE 2 ; 4H View FIGURE 4 ) protopod flattened and elongated, filling gap between pleonite 5 and pleotelson, surpassing distal margin of telson, and surpassing distal halt of exopod length; exopod inserted on median margin of uropod, endopod twice as long as exopod, inserted proximally to endopod.

Male. Pereopod 1 ( Fig. 2E View FIGURE 2 ; 4A View FIGURE 4 ) merus, carpus and ischium with short scale fields on sternal margin. Pereopod 7 ( Fig. 4B View FIGURE 4 ) ischium elongated; sternal margin concave; carpus slightly longer than merus; triangular lobe on rostral portion of merus absent. Genital papilla ( Fig. 4C View FIGURE 4 ) with triangular ventral shield and showing subapical orifices. Pleopod 1 exopod ( Fig. 4C View FIGURE 4 ) trapezoidal, distal margin roundedwider than long, bearing two small setae; endopod with tapering apex, bent outwards, inner margin with small setae. Pleopod 2 exopod ( Fig. 4D View FIGURE 4 ) subtriangular, distal margin elongated, tapering, outer margin covered by thin setae; endopod flagelliform, slightly longer than exopod. Pleopods 3–4 exopods as in Fig. 4E and F View FIGURE 4 , respectively. Pleopod 5 exopod ( Fig. 4G View FIGURE 4 ) subtriangular, apex elongated and slightly acute.