Ommatoiulus longicornis Akkari & Enghoff, 2018

Akkari, Nesrine, Gilgado, José D., Ortuño, Vicente M. & Enghoff, Henrik, 2018, Out of the dark void: Ommatoiulus longicornis n. sp., a new julid from Spain (Diplopoda, Julida) with notes on some troglobiomorphic traits in millipedes, Zootaxa 4420 (3), pp. 415-429 : 417-424

Ommatoiulus longicornis Akkari & Enghoff n. sp.

Figs 1–5

Material: Holotype: ♂ broken in 3 parts, Bèrnia, SSD 2, MSS, Xaló, Alicante, 38°39'52"N 0°3'8"W, 890 m a.s.l, 26 April 2012, Gilgado JD, Ortuño VM et al. leg. ( ZMUC 0 0 0 39888).

Paratypes: 1 ♂, Serrella, Quatretondeta, Alicante, MSS trap 4, 38°42'56"N 0°17'44"W, 16 May 2013, Gilgado JD, Ortuño VM et al. leg. ( ZMUC 0 0 0 39889); 1 ♂ broken in 3 parts, Serrella SSD 3. MSS, Quatretondeta, Alicante, 38°42'56"N 0°17'44"W, 1000 m a.s.l, 27 April 2012, Gilgado JD, Ortuño VM et al. leg. ( ZMUC 0 0 0 39890); 1 ♂ broken in 3 parts (photographed), Serrella SSD 3, MSS, Quatretondeta, Alicante, 38°42'56"N 0°17'44"W, 1000 m a.s.l, 27 April 2012, Gilgado JD, Ortuño VM et al. leg. ( NHMW 9213); 1 ♂ broken in 2 parts (SEM), Bèrnia, SSD 2, MSS, Xaló, Alicante, 38°39'52"N 0°3'8"W, 890 m a.s.l, 26 April 2012, Gilgado JD, Ortuño VM et al. leg. ( NHMW 9214); 1 ♂ broken in 2 parts (dissected), Bèrnia, SSD 2, MSS, Xaló, Alicante, 38°39'52"N 0°3'8"W, 890 m a.s.l, 26 April 2012, Gilgado JD, Ortuño VM et al. leg. ( NHMW 9215); 1 ♂ broken in 4 parts, Bèrnia SSD 3, MSS, Xaló, Alicante, 38°39'52"N 0°3'8"W, 890 m a.s.l, 14 May 2013, Gilgado JD, Ortuño VM et al. leg. ( NHMW 9216); 1 ♀, broken in 2 parts, Bèrnia, MSS, Xaló, Alicante, 38°39'52"N 0°3'8"W, 890 m a.s.l, 29 Nov 2013, Gilgado JD, Ortuño VM et al. leg. ( NHMW 9217); 1 subad. ♀, 1 juv., Serrella, Quatretondeta, Alicante, MSS trap 4, 38°42'56"N 0°17'44"W, 1000 m a.s.l, 30 Novembre 2013, Gilgado JD, Ortuño VM et al. leg. ( NHMW 9218); 1 ♂ broken in 3 parts, Serrella SSD 4, MSS, Quatretondeta, Alicante, 38°42'56"N 0°17'44"W, 1000 m a.s.l, 16 May 2013, Gilgado JD, Ortuño VM et al. leg. ( DZAF-UA /VMO); 1 ♂, Bèrnia, SSD 4, MSS, Xaló, Alicante, 38°39'52"N 0°3'8"W, 890 m a.s.l, 14 May 2013, Gilgado JD, Ortuño VM et al. leg. ( MNCN 20.07/2017); 1 ♂ Bèrnia, SSD 2, MSS, Xaló, Alicante, 38°39'52"N 0°3'8"W, 890 m a.s.l 29 Nov 2013, Gilgado JD, Ortuño VM et al. leg. ( MNCN 20.07/2018); 1 ♂ broken in 4 parts, Bèrnia SSD 3, MSS, Xaló, Alicante, 38°39'52"N 0°3'8"W, 890 m a.s.l, 14 May 2013, Gilgado JD, Ortuño VM et al. leg. ( DZAF-UA /VMO).

Diagnosis. A small species of the genus Ommatoiulus with notably elongated antennae; different from all congeners by the combination of: 1) a broad promerite with a protruding mesal ridge and a prominent scaly triangular lateral tooth; 2) a broad mesomerite (ca. 2/ 3 x promerite length), significantly shorter than the promerite, concave and bearing a lateral triangular thickening projecting anteriad; 3) a broad solenomerite with a ramified lamellar lateral fold.

Etymology. The species name is a Latin composite adjective referring to the long antennae.

Description. Based on males.

Measurements (mm): L: 22–31.6 mm, H: 1.56–1.86 mm, 43–51 PR + 1–2 AR + Telson; Antennae: 2.33–2.93 mm, midbody leg: 1.45–1.63 mm. Ratios: Antenna/H: 1.35–1.59; midbody leg/H: 0.83–1.03.

Colour ( Fig. 1 ): Prozonites light tawny-brown; metazonites pale, dorsum with a thin black mid-dorsal line; legs pale brown to yellowish; head dark brown on the frontal part, paler towards the labral zone, mouthparts yellowish; antenna brownish; preanal ring and anal valves pale.

Head ( Fig. 1B ): With remarkably long antennae; 9–11 vertical rows of ocelli, mouthparts as usual for Julida with three labral teeth, regular gnathochilarium, mandibles with strong biting parts; gnathal lobe with four pectinate lamellae and regular molar plate. Stipital lobes weakly developed.

Body rings ( Fig. 1 ): Prozonites with oblique striae; metazonites with regular striation and scattered setae; suture complete and rectilinear, sometimes with a sinus at ozopore level.

Legs ( Fig. 2A, C ): First pair of legs hook-shaped, the rest showing feebly developed postfemoral and tibial pads.

Anal valves ( Fig. 2B ): with a marginal row of short setae, a submarginal row of longer ones and 5–6 setae on disc. Subanal scale triangular, blunt and setose.

Preanal ring ( Figs 1A , 2B ): with a protruding caudal projection, bearing ca. seven setae on tip and a small upturned hyaline process.

Gonopods ( Figs 2D, E , 3 , 4 ): Promerite (P) three times as long as broad, parallel-sided basally; lateral margin thickening and expanding distally in a rounded lobe with a sub-lateral triangular process (Tp). Tp with a scaly surface and pointing postero-mesad ( Figs 2D , 3A , Da). Apical margin with two incisions separated by a small blunt tooth. Mesal ridge (Mr) somewhat broad, projecting distad in a meso-apical process. Rudimentary telopodite (T) large, located proximally ( Figs 2D , 3D ). Posterior gonopods ( Figs 2E , 3 A-C, 4): 2/3 shorter than promerite, mesomerite (Ms) broad ( Figs 4B, C ), slightly constricted at mid-length; anteriorly concave ( Figs 4B, C ); apical margin showing a small incision ( Fig. 4B ) and a lateral triangular thickening projecting anteriad (probably to clasp on Tp). Solenomerite (S) large, showing at mid-length an anterior small triangular process (Sa) bearing several short setae, pointing distad and connected to the main solenomerite branch by a jagged surface ( Fig. 2D ). Distal part of the solenomerite divided in 1) a posterior narrow conical process (Sp) with a folded apex showing scattered thorns and lodging the opening of the seminal groove (Og) and 2) a broad anterior hyaline lamella (Hl) extending in ramified branches protruding in small apical spikes ( Figs 2E , 4D, E ). Sp and Hl separated by a rounded notch (n). Seminal groove (g) running posteriorly from the fovea (F) located at the base of the solenomerite up to Og. Paracoxite (Px) stout and broad, distally folded, apical margin jagged and bent mesad; coxite low.

Distribution ( Fig. 5A ). Spain, Alicante. The species is recorded only in the Serra de Bèrnia and La Serrella.

Habitat. The species was exclusively found in MSS, which is supposed to have reduced fluctuations of temperature of the surface and a more or less constant and high relative humidity ( Pipan et al. 2011; Ortuño et al. 2013; Jiménez-Valverde et al. 2015; Mammola et al. 2016). However, the screes where the species was collected are strongly influenced by the surface conditions ( Fig. 5B ).

The Serra de Bèrnia reaches a maximum altitude of 1128 m asl. The sampling points are located at an average of 890 m asl. The scree is composed by Eocene limestone ( Morales Gil et al. 1983), and the average temperatures in the surface are around 16ºC with minimum temperatures in January around -7ºC. The scree is to some extent fixed by plants like Hedera helix L., with other botanical elements in the surroundings like the relict Taxus baccata L. and other autochthonous species (Gil et al. 1983), i. e., Amelanchier ovalis Medik , Fraxinus ornus L., Pistacia terebinthus L., Acer monspessulanum L., Malva cretica althaeoides (Cav.) Dalby , Saponaria ocymoides L., Aphyllanthes monspeliensis L., Asplenium fontanum (L.) Bernh., Brachypodium retusum (Pers.) P. Beauv. , Arrhenatherum elatius sardoum (E. Schmid) , Koeleria vallesiana (Honckeny) Gaud. , Juniperus phoenicea L., Festuca capillifolia Dufour ex Roem. and Schult. , Thapsia villosa L. and some Pinus halepensis Mill.

The Serrella reaches a maximum altitude of 1379 m asl, although the sampling points are located at an average of 1000 m asl. The screes are composed of Oligocene and Eocene limestone ( Coll 1988). The mountain has a Mediterranean climate with a little continental influence and an average temperature around 11ºC, maximum of 36ºC and minimal of -6ºC, according to the closest meteorological observatory (Meteoclimatic Rainbow ss 2015). Annual average precipitations are above 1250 mm, with peaks in autumn and spring ( Coll 1988). In the scree and the crevices of the rocky wall above it there are some rupicolous species as Teucrium buxifolium Schreb. , Asplenium petrarchae (Guérin) DC., Rhamnus lycioides L., and H. helix . In some shade zones of the mountain, there are pastures of Brachypodium phoenicoides (L.) Roem. y Schult. and Brachypodium retusum (Pers.) Beauv. , with presence of some relict T. baccata and the last Ilex aquifolium L. of Alicante (Mateo Sanz & Solanas i Ferràndiz 2005; Crespo et al. 2007).

Figures

FIGURE 1. Ommatoiulus longicornis n. sp., paratype male (ZMUC 00039889), habitus, lateral view. A—animal in toto, B— anterior part.

FIGURE 2. A‒B Ommatoiulus longicornis n. sp., holotype (ZMUC 00039888). A—Mid-body leg, B—Telson, ventral view, C‒E paratype (NHMW 9214), C—first pair of legs, posterior view, D—Right promerite, posterior view, E—Right posterior gonopod, mesal view (images not to scale). Abbreviations: F fovea, g seminal groove, Hl hyaline lamella, Mr mesal ridge, Ms mesomerite, Og opening of the seminal groove, Px paracoxite, Sa anterior process, S solenomerite, Sp posterior conical process, T telopodite, Tp triangular process.

FIGURE 3. Ommatoiulus longicornis n. sp., paratype (NHMW 9214), Gonopod structures. A—Left gonopod, mesal view, B—Left gonopod, antero-lateral view, C—Left gonopod, posterior view, D—Left promerite, posterior view, Da—Detail of the lateral tooth and its scaly surface of the right promerite. Abbreviations: Mr mesal ridge, Ms mesomerite, P promerite, Px paracoxite, S solenomerite, T telopodite, Tp triangular process.

FIGURE 4. Ommatoiulus longicornis n. sp., paratype (NHMW 9214), A-C Left posterior gonopod: A—Mesal view, B— Antero-mesal view, C—Antero-lateral view, D—Details of the distal part of the right solenomerite, E—Right posterior gonopod, apical view. Abbreviations: F fovea, g seminal groove, Hl hyaline lamella, Ms mesomerite, n notch, Og opening of the seminal goove, Px paracoxite, S solenomerite, Sp posterior conical process.

FIGURE 5. A—Sampling localities in northern Alicante province, Spain. B—Temperature (dark lines) and relative humidity (pale lines) for the localities where Ommatoiulus longicornis n. sp. was captured, both in the MSS and on the surface (“Ext”), during a year of sampling.