Alainites bengunn Yanai & Gattolliat, 2022

Yanai, Zohar, Sroka, Pavel & Gattolliat, Jean-Luc, 2022, Two new species of Alainites (Ephemeroptera, Baetidae) from the Mediterranean biodiversity hotspot, ZooKeys 1118, pp. 73-95 : 73

Alainites bengunn Yanai & Gattolliat sp. nov.

Figs 1 , 2 , 3

Alainites muticus in Buffagani et al. 2003

Alainites cf. muticus in Gattolliat et al. 2015

Takobia sp. cf. albinatii in Tenchini et al. 2018

Material examined.

Holotype. 1 nymph, Italy, Sardinia, Loc near Fonni, trib. of Taloro (SA27), 40°09.05'N, 9°16.37'E, alt. 810 m a.s.l., 15.v.2009, L. Vuataz, E. Cavallo & Y. Chittaro leg., MZL (GBIFCH 00970536) . Paratypes. Italy. 3 nymphs (2 on slide), same details as holotype, SMNH, IECA, MZL (GBIFCH 00280204, GBIFCH 00604446, GBIFCH 00604447) • 21 nymphs (2 on slide), Sardinia, Monti del Genargentu, near Monte Spada, 20.vi.2010, T. Soldán leg., MZL (7 nymphs), SMNH (7 nymphs), IECA (7 nymphs) • 33 nymphs (2 on slide), Sardinia, tributary of Fiume Taloro Riv., Fonni village , 20.vi.2010, T. Soldán leg., MZL (11 nymphs), SMNH (11 nymphs), IECA (11 nymphs) • 35 nymphs (2 on slide), Sardinia, Riu Pramaera River , Lotzorai village , 21.vi.2010, T. Soldán leg., MZL (11 nymphs), SMNH (11 nymphs), IECA (13 nymphs). Additional non-type material. Italy. 3 nymphs, Sardinia, Rio Rumine, vicinity of Mamoiada village, 20.vi.2010, T. Soldán leg., IECA • 1 nymph, Sardinia, Genna Stream, Auxi Pass, vicinity of Urzulei village , 21.vi.2010, T. Soldán leg., IECA .

Material not examined.

Italy. Sardinia, Loc. Siligo village , 40°35.36'N, 8°43.55'E, alt. 240 m a.s.l., C. Belfiore leg.

Differential diagnosis.

The species is distinct amongst other West Palaearctic Alainites species based on the combination of (1) six pairs of abdominal gills, (2) paraproct prolongation covered with spines on its entire surface, (3) serration between prostheca and mola, and (4) low number of dorsal setae on its fore-femora (14-20) and relatively many of them on the fore-tibiae (up to 17).

Description of nymph.

Length. Female body 7.0-7.9 mm; cerci 4.5-5.5 mm; median caudal filament ca. 2/3 of cerci. Male body 6.0-6.7 mm; cerci 4.0-5.0 mm; median caudal filament ca. 2/3 of cerci.

Colouration (Fig. 1 ). General colouration brown. Head uniformly brown with vermiform marks on vertex and frons. Legs ecru except upper side of femora brown. Thorax brown with some paler area, but without clear pattern. Abdominal tergites brown with a central yellowish elongated dot; distal part of tergite IX and whole tergite X yellowish. Abdominal sternites I and II yellowish, III-IX pale brown. Cerci ecru to pale brown.

Head. Antennae (Fig. 2A ) close to each other, with a narrow interantennal carina; scape with few deep scale insertions. Dorsal surface of labrum (Fig. 2B ) with one central long seta and distolateral arc of four medium to long, simple, stout setae, and small fine setae scattered on surface; ventral surface with 5-6 submarginal small, pointed setae; distal margin fringed with ca. 20 short, followed by seven or eight long, feathered setae. Right mandible (Fig. 2C ) slightly shagreened, with sparse fine setae and deep scale insertions; incisors composed of eight apically rounded, distinct denticles, outer- and innermost denticles smaller than others; prostheca reduced and bifid with numerous thin setae; space between prostheca and mola serrated, tuft of setae absent; apex of mola with tuft of two setae. Left mandible (Fig. 2D ) slightly shagreened, with sparse fine setae and deep scale insertions; incisors composed of eight rounded, distinct denticles, outer- and innermost denticles smallest, and small denticle in the middle; prostheca with few medium denticles and comb-shaped structure; margin between prostheca and mola serrated, without setae; tuft on apex of mola reduced to one seta. Hypopharynx (Fig. 2E ) trilobed, apically sparsely covered with thin setae; lingua with no central protuberance; superlingua subequal to lingua. Maxillae (Fig. 2F ) apex with three elongated and curved teeth and a tooth-like dentiseta; crown with two rows of setae, first row with small setae, second row with two long stout feathered dentisetae; palp two-segmented, extending the apex of galealacinia, length of segment I approximately 0.75 × segment II; segment II apically rounded, with sparse thin setae. Labium (Fig. 2G ) with glossae slightly shorter than paraglossae; inner margins of glossae with eight or nine stout medium setae, apical margin with ca. nine long stout setae; ventral surface with few thin scattered setae; dorsal surface with row of ca. six medium setae; paraglossae with three rows of eight or nine long, stout, simple setae apically; labial palp three-segmented; segment I 0.75 × length of segments II and III combined; segment II with dorsal oblique row of five medium setae; segment III rounded, nearly symmetrical, slightly pointed apically, covered with few short thin setae.

Thorax. Forelegs (Fig. 3A ). Trochanter with four or five marginal short stout pointed setae and few similar setae on surface. Femora dorsally with one row of 14-20 long, stout setae, and very few setae subparallel to dorsal margin; dorsoapical setal patch formed by two stout, long setae; ventrally several marginal and submarginal short stout pointed setae; lateral surface with scale bases, mainly on apical half and along subdorsal area. Tibiae dorsally with 9-17 short stout pointed setae, denser towards apical end, few proximal minute setae; ventrally with marginal and submarginal short stout pointed setae, denser towards apical end; tibiopatellar suture present; lateral surface with few short, stout, pointed setae and numerous scale bases. Tarsi bare dorsally; ventral margin with ca. 20 pointed medium setae; lateral surface with numerous scale bases. Tarsal claws (Fig. 3B ) hooked with one row of 10-15 medium teeth, apical setae absent. Mid and hindlegs similar to forelegs except femora dorsally with 13-25 pointed setae and tibiae (Fig. 3C ) with 11-18 similar setae dorsally. Hindwing pads present.

Abdomen. Terga (Fig. 3D ) shagreened, with numerous scale bases, distal margin of tergite IV with triangular spines about twice longer than broad. Sterna shagreened with scales and scale bases; posterior margin smooth without spination. Gills (Fig. 3E ) on segments II-VII, elliptical, almost symmetrical and with serrated margins, except proximal part; tracheation well visible and well branched; gill VII similar to gills II to VI. Paraproct (Fig. 3F ) with abundant scale bases but almost no setae; margin with ca. seven broad, triangular spines inner to prolongation and numerous medium spines outer to prolongation; prolongation covered with numerous small spines; cercotractor with scattered scale bases, margin with ca. 20 small spines.

Imagos.

Unknown.

Etymology.

The species is endemic to an island, just like Ben Gunn who was deserted and isolated on an island by his crewmates in "Treasure Island" by R.L. Stevenson (1850-1894).

Distribution and ecology.

Little is known about the ecology and distribution of this species. The type locality is a small stream (less than three meters wide), shallow, and with medium current velocity. The species is only known from Sardinia where it is apparently not frequent and not very abundant.

Figures

Figure 1. Alainites bengunn sp. nov., habitus: lateral view (top) and dorsal view (bottom).

Figure 2. Alainites bengunn sp. nov., nymph, characters of the head A antenna base B labrum (left side dorsal view, right side ventral view) C right mandible (ventral view) D left mandible (ventral view) E hypopharynx F maxilla G labium (left side dorsal view, right side ventral view). B-G presented to the same scale.

Figure 3. Alainites bengunn sp. nov., nymph, characters of the thorax and abdomen A foreleg B tarsal claw of foreleg C tibia of midleg D distal margin of tergum IV E gill IV F paraproct (with detail of prolongation).