Pectenoniscus liliae Campos-Filho, Bichuette & Taiti, 2019

Campos-Filho, Ivanklin Soares, Fernandes, Camile Sorbo, Cardoso, Giovanna Monticelli, Bichuette, Maria Elina, Aguiar, José Otávio & Taiti, Stefano, 2019, Two new species and new records of terrestrial isopods (Crustacea, Isopoda, Oniscidea) from Brazilian caves, Zootaxa 4564 (2), pp. 422-448 : 430-434

Pectenoniscus liliae Campos-Filho, Bichuette & Taiti sp. n.

Figs 8–10, 17C

Zoobank. urn:lsid:zoobank.org:act:FD823E4A-5236-462F-8419-037747EC6365 .

Pectenoniscus sp. 2 Gallão & Bichuette, 2018: 12, table 2.

Etymology. The new species is named after Lília Senna-Horta, speleologist of the Grupo Bambuí de Pesquisas Espeleológicas (GBPE), who collected part of the material examined here and greatly contributed to the knowledge of the Brazilian subterranean fauna and its conservation.

Material examined. Holotype Bahia, Coribe: male ( LES 14350 ), Caverna Chico Pernambuco cave, 13°49’10”S, 44°04’15”W, 28 July 2012, leg. M.E. Bichuette, J.E. Gallão, L. Senna-Horta and P.P. Rizzato. Paratypes 1 male (in micropreparations), 2 females (one in micropreparations) ( LES 6449 ), same data as holotype ; 1 female ( LES 6419 ), Gruna do Enfurnado cave , 13°38’45.69”S, 44°12’8”W, 24 November 2006, leg. E. Trajano and D. Sansone ; 1 female ( LES 6420 ), same locality, 5 May 2007, leg. E. Trajano and D. Sansone.

Description. Maximum body length: male 3 mm, female 2.5 mm.

Body outline as in Fig. 8A. Dorsal scale-setae tricorn-shaped ( Fig. 8C). Dorsal granulations diminishing in size from cephalon to pereonite 7; granules disposed in three rows on pereonite 1 and two rows on pereonites 2 to 7 ( Figs 8A, B, 17C). Cephalon ( Figs 8A, B, 9A) with quadrangular antennal lobes obliquely directed and slightly grooved dorsally; suprantennal line almost straight. Pereonites 1 and 2 with posterior margins straight, pereonites 3–7 gradually arched; pereonite 1 with anterior corners not surpassing median portion of cephalon ( Fig. 8A, B). Pleon with epimera 3–5 reduced ( Fig. 8A). Telson ( Fig. 9B) with distal margin rounded.

Antennula ( Fig. 9C) with distal article longest bearing nine aesthetascs. Antenna ( Fig. 9D) short, slightly surpassing pereonite 3; flagellum of three articles longer than fifth article of peduncle, apical organ as long as distal article of flagellum.

Right mandible ( Fig. 9E) with lacinia mobilis cleft and one penicil, left mandible ( Fig. 9F) with two penicils. Maxillula ( Fig. 9G) inner endite with one stout penicil on distal margin and two lateral penicils, proximal one longest; outer endite with of 4+5 simple teeth and two plumose stalks. Maxilla ( Fig. 9H) of two rounded lobes covered with thick and thin setae. Maxilliped ( Fig. 9I) with palp bearing two setae, subequal in length, on proximal article, and many setae on outer margin; endite subrectangular, distal margin with two triangular spines and stout hairy penicil.

Uropod ( Fig. 10A) protopod subquadrangular, exopod longer than endopod.

Pereopod 1 ( Fig. 10B) carpus with longitudinal antennal grooming brush, pereopods 6 and 7 ( Fig. 10C, D) bearing water conducting system; dactylus with dactylar seta bifid bearing thin setae.

Male. Pereopods 6 and 7 propodus with dense tufts of setae on tergal margin ( Fig. 10C, D); pereopod 7 ischium with convex sternal margin. Genital papilla ( Fig. 10E) enlarged on medial portion, apical portion narrow and elongated. Pleopod 1 ( Fig. 10F) protopod subrectangular, almost three times as wide as long, outer margin cleft bearing thin setae; exopod triangular; endopod twice as long as exopod. Pleopod 2 ( Fig. 10G) protopod subrectangular; exopod ovoid, twice as wide as long; endopod with distal article three times as long as proximal article, apical portion chela-shaped with two triangular lobes. Pleopod 3–5 exopods ( Fig. 10 H–J) subquadrangular, bearing four to five setae, outer margin convex.

Remarks. The genus Pectenoniscus was erected by Andersson (1960) to include the new species P. angulatus from Nova Teutônia, state of Santa Catarina. After the original description of this species, many surveys have been conducted in the type locality but the species has never been recollected.

Pectenoniscus liliae sp. n. shows all the characters of the genus as listed by Andersson (1960), except for the epimera of the pleonites which are well developed in P. angulatus and reduced in the new species. This character may be a specific rather than a generic character. One of the most remarkable characteristics of the genus is the arrangement of the aesthetascs on the distal article of the antennule. These aesthetascs are stout, long and longitudinally arranged in one line from the median to the apical portion of the distal article, resembling a comblike structure.

The new species is readily distinguishable from P. angulatus in having quadrangular instead of triangular antennal lobes, reduced pleon epimera, male pereopod 7 ischium not enlarged, and the complex chela-shaped apex of the male pleopod 2 endopod.

This species is considered here as troglobiotic and endemic to two caves from Serra do Ramalho karst area, state of Bahia, northeastern Brazil: Chico Pernambuco and Gruna do Enfurnado. As previously stated, the caves are not legally protected and their surrounding is used mainly for agriculture and pasture activities; moreover, the area is also threatened by future installation facilities for mining activities. However, both caves are relatively isolated and Chico Pernambuco is a technical one, with no impact related to tourism or uncontrolled visitation. The specimens of the new species of Pectenoniscus were collected in extremely humid substrate, composed by silt and organic matter (bat guano and vegetal debris), always close to water bodies.