Metaprosekia igatuensis Campos-Filho, Fernandes & Bichuette 2020, sp. nov.
Creators: name: Campos-Filho, Ivanklin Soares
name: Fernandes, Camile Sorbo
name: Cardoso, Giovanna Monticelli
name: Bichuette, Maria Elina
name: Aguiar, José Otávio
name: Taiti, Stefano
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Philosciidae
Metaprosekia
Metaprosekia igatuensis

description: Metaprosekia igatuensis Campos-Filho, Fernandes & Bichuette sp. nov.
urn:lsid:zoobank.org:act: 24B7CEE5-59B7-4943-AA9A-D50D79BD995D
Figs 8–10, 14
Metaprosekia sp. – Fernandes et al. 2019: 1108, table 1.
Diagnosis
Telson with lateral sides almost straight, mandibles with molar penicil simple, maxillula outer endite of 4+5 teeth (two apically cleft), male pleopod 1 exopod subtriangular with outer and inner margins slightly convex, male pleopod 2 endopod with distal portion slender.
Etymology
This new species is named after the locality where the specimens were collected, Povoado de Igatu, which holds a high diversity of subterranean fauna.
Material examined
HolotypeBRAZIL –Bahia State, Andaraí• ♂; Povoado de Igatu, Gruna Rio dos Pombos; 12°54′12″ S, 41°19′04″ W; 31 Feb. 2013; M.E. Bichuette, J.E. Gallão and D.M. Schimonsky leg.; LES 6349.
ParatypesBRAZIL • 1 ♂, 3 ♀♀, 1 juv.; same collectiondata as for holotype; parts of ♂ and 1 ♀ in micropreparations; LES 6349.
Description
MEASUREMENTS. Maximum body length: male and female 2 mm.
BODY. Body pigment absent. Body outline as in Fig. 8A; dorsal surface densely covered with fan-shaped scale-setae (Fig. 8B). Noduli laterales piliform (Fig. 8C); d/c and b/c coordinates as in Fig. 8 D–E.
CEPHALON. Lateral lobes and frontal line absent; suprantennal line bent downwards in middle; eyes composed of four ommatidia (Fig. 8A, F).
PEREON. Pereonite 1 epimera with anterior corners slightly directed frontwards; pereonites 1–4 with posterior margins straight, 5–7 gradually arched (Fig. 8A).
PLEON. Slightly narrower than pereon, epimera of pleonites 3–5 short and directed backwards; telson more than twice as long as wide, triangular with lateral margins almost straight, with rounded apex (Fig. 8G).
ANTENNULA. Composed of three articles, proximal article longest, distal article conical, bearing one lateral tuft of five aesthetascs plus apical pair (Fig. 8H).
ANTENNA. Reaching pereonite 3 when extended backwards; flagellum of three articles, medial and distal articles subequal in length; apical organ long, bearing two short free sensilla (Fig. 8I).
MOUTH. Mandibles with dense cushion of setae on incisor process, molar process simple, left mandible (Fig. 9A) with 2+1 penicils, right mandible (Fig. 9B) with 1+1 penicils. Maxillula (Fig. 9C) inner endite with two apical penicils and small triangular point; outer endite with 4+5 teeth, inner set with two teeth apically cleft. Maxilla (Fig. 9D) inner lobe rounded, covered with thick setae; outer lobe rounded, three times as wide as inner lobe, covered with thin setae. Maxilliped (Fig. 9E) palp with two setae on proximal article; endite subrectangular, medial seta surpassing distal margin, distal margin bearing outer tip, rostral surface with setose sulcus ending with one short penicil.
PEREOPODS. Pereopod 1–7 merus to propodus bearing sparse setae on sternal margin, pereopod 1 carpus with short transverse antennal grooming brush and distal seta hand-like; dactylus of two claws, inner claw shorter, dactylar seta simple, not surpassing outer claw, ungual seta simple, slightly surpassing outer claw.
UROPOD. Protopod subquadrangular; protopod and exopod outer margins grooved, bearing glandular pores; exopod twice as long as endopod, endopod inserted proximally (Fig. 10A).
PLEOPOD EXOPODS. Without respiratory areas.
Male
PEREOPODS 1 AND 7. Without sexual dimorphism (Fig. 10B–C).
GENITAL PAPILLA. Bearing triangular ventral shield, papilla slightly longer than ventral shield, bearing two subapical orifices (Fig. 10D).
PLEOPODS. Pleopod 1 (Fig. 10E) exopod subtriangular, with outer and inner margins slightly convex; endopod more than twice as long as exopod, distal portion tapering, slightly directed outwards and bearing small setae on medial margin. Pleopod 2 (Fig. 10F) exopod triangular, outer margin concave bearing one seta; endopod flagelliform, longer than exopod. Exopods of pleopods 3 and 4 as in Fig. 10G and H, respectively. Pleopod 5 exopod (Fig. 10I) rhomboid, outer margin convex, bearing five long setae, inner margin grooved to accommodate pleopod 2 endopod.
Remarks
The genus Metaprosekia comprises three species: M. nodilinearis Leistikow, 2000 from the department of Merida, Venezuela; M. caupe Campos-Filho, Araujo & Taiti, 2014 and M. quadriocellata CamposFilho, Araujo & Taiti, 2014 fromthestateof Pará, Brazil (Leistikow 2000; Campos-Filho et al. 2014). The genus is mainly defined by its small size, dorsal surface covered with fan-shaped or pointed scale-setae, epimera of pereonites 1–7 with noduli laterales inserted at same level from lateral margins, cephalon with suprantennal line and eyes of 3–4 ommatidia, antennula with one lateral tuft of aesthetascs plus apical pair, maxillula outer endite with 4+4 teeth (some of them cleft at apex), maxilliped endite with rostral penicil and pleopod exopods without respiratory structures (see Leistikow 2000; Campos-Filho et al. 2014).
The new species differs from other species of the genus in having the mandibles with molar penicil simple instead of dichotomized, the shape of the male pleopod 1 and male pleopod 2 endopod, with the distal portion slender rather than thick. Moreover, it differs in having the suprantennal line bent downwards in the middle (vs. straight in M. caupe and M. nodilinearis; slightly bent downwards in M. quadriocellata) and in having the apical organ of the antennal flagellum shorter than the distal article (vs subequal in M. caupe; longer in M. nodilinearis and M. quadriocellata).
The presence of fan-shaped scale-setae is related with the creeper eco-morphological strategy (Schmalfuss 1984), which functionally reduces the adhesive forces and facilitates the movement of the animal in unconsolidated substrates. However, this is not the case for species of Metaprosekia. As mentioned by Campos-Filho et al. (2014), the presence of fan-shaped scale-setae on the dorsal surface and of eyes with a reduced number of ommatidia can be related to an endogean life-style. This species is considered here as troglobiotic, since many expeditions were carried out outside the cave where it was collected and no specimens were found.
description: Published as part of Campos-Filho, Ivanklin Soares, Fernandes, Camile Sorbo, Cardoso, Giovanna Monticelli, Bichuette, Maria Elina, Aguiar, José Otávio & Taiti, Stefano, 2020, New species and new records of terrestrial isopods (Crustacea, Isopoda, Oniscidea) of the families Philosciidae and Scleropactidae from Brazilian caves, pp. 1-38 in European Journal of Taxonomy 606 on pages 18-21, DOI: 10.5852/ejt.2020.606, http://zenodo.org/record/3676984