Miktoniscus longispina Reboleira & Taiti, 2015

Reboleira, Ana Sofia P. S., Gonçalves, Fernando, Oromí, Pedro & Taiti, Stefano, 2015, The cavernicolous Oniscidea (Crustacea: Isopoda) of Portugal, European Journal of Taxonomy 161, pp. 1-61 : 28-32

Miktoniscus longispina Reboleira & Taiti sp. nov.

urn:lsid:zoobank.org:act:6B9A5E8B-53F8-408D-B3BA-8E10BCE20717

Figs 18 A–F, 19A–E, 20A–D

Diagnosis

A species of Miktoniscus characterised by a depigmented body, the male pereopod 7 having a long and stout seta on the distal corner of the ischium, and a triangular male pleopod 1 exopod.

Etymology

From Latin longus = long + spina = spine. The name of the new species refers to the long, thick seta on the distal part of the male pereopod 7.

Material examined

Holotype

PORTUGAL: ♂, Gruta dos Bolhos, Cesaredas Plateau, 26 Dec. 2010 ( MZUF).

Paratype

PORTUGAL: 1 ♀, same locality as holotype, Feb. 2009 ( MZUF).

Additional material

PORTUGAL: 1 ♂, 2 ♀♀, Gruta da Cerâmica, Sicó Massif, 10 Jun. 2011 ( MZUF); 2 ♂♂, 3 ♀♀, same locality, 2 Mar. 2013 ( SR); 1 ♂, 1 ♀, Algar da Ervilha, Sicó, 30 Mar. 2014 ( ZMUC).

Description

Maximum size: ♂ and ♀ 3.5 ×1.0 mm. Body depigmented, elongated ( Fig. 18A ). Dorsum of cephalon and pereon distinctly granulated, each granule bearing a scale-seta on top ( Fig. 18B ). Cephalon ( Fig. 18C ) with no frontal lobes. Eye consisting of single black ocellus (lacking in specimens from Gruta da Cerâmica and Algar da Ervilha). Pereonites 1–4 with rounded posterior corners; pereonites 5–7 with epimera pointing backwards ( Fig. 18A ). Pleon ( Fig. 18A, D ) slightly narrower than pereon; pleonites 3–5 with reduced epimera and very short posterior points. Telson ( Fig. 18D ) about twice as wide as long, with rectangular basal part and trapezoidal distal part, with almost straight sides. Antennula ( Fig. 18E ) with three articles; third article with short spine and four long aesthetascs at apex (five in specimens from Gruta da Cerâmica and Algar da Ervilha). Antenna ( Fig. 18F ) with fifth article of peduncle slightly longer than flagellum; flagellum with four articles, with one aesthetasc on second article and two aesthetascs on third article (two and four, respectively, in specimens from Gruta da Cerâmica and Algar da Ervilha). Mandibles ( Fig. 19 A–B) with one penicil on the right and two on the left; molar process without penicils. Maxillula ( Fig. 19C ) with inner branch bearing three penicils at apex, diminishing in size from proximal to distal; outer branch with nine teeth and thin stem. Maxilla ( Fig. 19D ) apically bilobed, outer lobe smaller and shorter than inner one; inner lobe with line of several long, stout setae near apical and inner margins. Maxilliped ( Fig. 19E ) endite triangular, with stout triangular penicil at apex; palp elongated, with long setae on margin of apical part, and basal article with two short, simple setae. Uropod ( Fig. 18E ) with exopod distinctly longer than endopod and more distally inserted.

MALE. Pereopod 1 ( Fig. 20A ) with no distinct sexual modifications. Pereopod 7 ( Fig. 20B ) ischium triangular, with strong seta, as long as merus, at corner between distal and sternal margin; sternal margin of merus sinuous, with one recurved seta and one pointed seta in the middle; carpus with distal part enlarged, with some strong setae on sternal margin. Pleopod 1 ( Fig. 20C ) exopod triangular, about twice as long as wide; endopod with basal article distinctly shorter than distal article, which is slightly enlarged subapicaly, with triangular and crenulated apical part. Pleopod 2 ( Fig. 20D ) exopod triangular, with distinctly concave outer margin; endopod biarticulated, distal article fusiform, elongated, about four times as long as first article.

Remarks

At present, the genus Miktoniscus includes 15 species distributed in the Americas and Western Europe, including the Atlantic islands ( Schmalfuss 2003). The new species is readily distinguishable from all species in the genus by the presence of a strong and long seta at the distal corner of the male pereopod 7 ischium. In continental Portugal and northwestern Spain only one species was previously known, Miktoniscis bisetosus Vandel, 1946 , from which M. longispina Reboleira & Taiti sp. nov. also differs in lacking a recurved seta on the male pereopod 7 carpus and in having the male pleopod 1 exopod with an acute, rather than broadly rounded, apex. The new species occurs in two distinct massifs of central Portugal, on the west border of Cesaredas Plateau near the Atlantic coast, and in Gruta da Cerâmica and Algar da Ervilha in the centre of Sicó Massif. Some differences are present in the specimens from Sicó compared with the type specimens from Cesaredas, i.e., the lack of visible eyes and the different number of aesthetascs on the antennula and antennal flagellum. For this reason, we have not designated the additional material as paratypes. However, since the male characters are the same in all these populations, we consider them as belonging to the same species.

Figures

Fig. 18. Miktoniscus longispina Reboleira & Taiti sp. nov. from Gruta dos Bolhos, Cesaredas Plateau. — Paratype, ♀. A. Specimen in dorsal view. — Paratype, ♂. B. Dorsal scale-seta. C. Cephalon in dorsal view. D. Pleonite 5, telson and left uropod. E. Antennula. F. Antenna.

Fig. 19. Miktoniscus longispina Reboleira & Taiti sp. nov. from Gruta dos Bolhos, Cesaredas Plateau, paratype, ♂. A. Right mandible. B. Left mandible. C. Maxillula. D. Maxilla. E. Maxilliped.

Fig. 20. Miktoniscus longispina Reboleira & Taiti sp. nov. from Gruta dos Bolhos, Cesaredas Plateau, paratype, ♂. A. Pereopod 1. B. Pereopod 7. C. Pleopod 1. D. Pleopod 2.