Labiobaetis alahmadii Gattolliat & Al Dhafer

Gattolliat, Jean-Luc, Kondratieff, Boris C., Kaltenbach, Thomas & Dhafer, Hathal M. Al, 2018, Labiobaetis from the Kingdom of Saudi Arabia (Insecta, Ephemeroptera, Baetidae), ZooKeys 774, pp. 77-104: 77

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Labiobaetis alahmadii Gattolliat & Al Dhafer

sp. n.

Labiobaetis alahmadii Gattolliat & Al Dhafer  sp. n.

Type material.

Holotype: Female larva (GBIFCH00521579): Saudi Arabia (AR43a); Wadi Shahadan; 17°28'36"/ 42°51'25"; Alt. 460m; 12.XI.2012; Coll. J-L Gattolliat.

Paratypes: 151 larvae (GBIFCH00235715, GBIFCH00235720 + GBIFCH00517525 + 3 slides GBIFCH00235737, GBIFCH00235755, GBIFCH00235757 (Genetics), GBIFCH00235737) + 8 larvae (KSU: GBIFCH00526208): same data as holotype.

47 larvae (GBIFCH00235710) + 10 larvae (KSU: GBIFCH00526227): Saudi Arabia (AR43b); Wadi Shahadan; 17°28'17"/ 42°51'14"; Alt. 455m; 12.XI.2012; Coll. J-L Gattolliat.

29 larvae (GBIFCH00235727) + 6 larvae (KSU: GBIFCH00526223): Saudi Arabia (AR39); Wadi Damad; 17°12'21"/ 43°01'35"; Alt. 260m; 11.XI.2012; Coll. J-L Gattolliat.

15 larvae (GBIFCH00235709 + 3 slides GBIFCH00235744, GBIFCH00235747 (Genetics), GBIFCH00465155 (Genetics) + GBIFCH00517526 (Genetics), GBIFCH00517527 (Genetics)) + 4 larvae (KSU: GBIFCH00526179): Saudi Arabia (AR44); Wadi Shahadan; 17°28'36"/ 42°42'50"; Alt. 190m; 13.XI.2012; Coll. J-L Gattolliat.

Differential diagnosis.

Larva: Colouration: mesothorax medium brown with a W-shaped yellow pattern; tergites I-VIII medium brown with two broad ecru spots, tergites IX and X yellow (Figs 32, 33). Scape of antenna without distolateral process (Fig. 28). Segment II of the maxillary palp with a small distomedial concavity (Fig. 23). Segment II of labial palp with a broad apically rounded triangular distomedial projection (Fig. 24). Dorsal margin of femur with regularly spaced setae; ventral margin almost bare (Fig. 25). Dorsal margin of tibia with a row of small spatulate setae (Fig. 26). Paraproct with approximately eight stout, pointed spines increasing in length toward the apex (Fig. 31).


Larva.Length: fully grown female: Body 9.5-10.6 mm, cerci 4.0-4.2 mm, terminal filament 2.9-3.1 mm. Fully grown male: Body 8.8-9.9 mm, cerci 3.8-4.1 mm, terminal filament 2.8-2.9 mm.

Colouration (Figs 32, 33): head almost uniformly medium brown, with darker, vermiform marking on vertex and frons, border of sclerites yellow. Prothorax ecru with proximal margin medium brown and a brown dot medio-apically; mesothorax medium brown with a double V-shaped yellow pattern; metathorax medium brown. Legs: ecru except femora with a central brown spot and apex of femora, tibiae and tarsi brown. Tergites I-VIII medium brown with two broad ecru spots sometimes fused medially, tergites IX and X yellow. Abdominal sternites ecru getting darker and brownish after sternite VI. Cerci ecru without dark stripe.

Head: scape of antenna without distolateral process (Fig. 28).

Labrum (Fig. 20) rounded, with a small anteromedial emargination, dorsally with a relatively short submedian seta and a distolateral row of approx. ten feathered setae; short, thin, simple setae scattered on dorsal surface of labrum; distal margin bordered with feathered setae.

Right mandible (Fig. 21): canine with two almost fused incisivi each with four denticles, outer denticle much shorter than others, inner margin of inner incisive with a row of very thin setae; stout prostheca apically with numerous small rounded denticles, also covering distoapical corner; margin between prostheca and mola slightly convex, smooth, without setae; tuft of setae at apex of mola present.

Left mandible (Fig. 22): canine with two almost fused incisivi each with four denticles, outer denticle much shorter than others; stout prostheca apically with small denticles and a comb-shaped structure; margin between prostheca and mandible slightly concave, without crenulations; tuft of setae at apex of mola present.

Hypopharynx similar to Fig. 6.

Maxilla with a medioapical row of medium setae, basal end of row with a few long setae; posterior side of lacinia mediobasally with a row of four medium-sized setae, a single small seta close to the medial margin of lacinia; palp 2-segmented, as long as galea-lacinia, segment II with distomedial concavity (Fig. 23).

Labium (Fig. 24) with glossae shorter than paraglossae; glossae with medium to long simple setae in apical half; paraglossae stout, apically rounded, with three rows of setae: two rows with simple setae and one row with setae feathered on one side; labial palp with segment I slender, quadrangular, as long as segments II and III combined; segment II with an elongated triangular distomedial projection with few scattered thin setae, on posterior side with a row of three medium setae; segment III subconical, with abundant scattered short thin setae and stouter setae.

Thorax: hind wing pads present.

Legs (Fig. 25): forefemur dorsally with a row of medium-sized, apically rounded setae, abundant proximally; apex with one short stout seta and minute setae; ventral margin with a poorly developed villopore and scarce minute setae. Foretibia dorsally with a row of short spatulate setae (Fig. 26); ventrally with short setae, not longer apically, apex with a patch of numerous flattened short setae. Foretarsus dorsally with a row of short spatulate setae; ventral margin with a row of minute pointed setae slightly increasing in length toward apex; tarsal claw (Fig. 27) with a single row of approx. 14 pointed teeth; without subapical setae. Middle and hind legs similar to foreleg but with reduced setation.

Abdomen: tergites (Fig. 30) with numerous scale bases with a few setae; posterior margin with triangular spination as long as broad. Sternites with numerous scales and scale bases; sternites I-VII with posterior margin smooth without spines, sternites VIII and IX with small triangular spines.

Gills present on abdominal segments I–VII, margins serrated, tracheation poorly marked and poorly divided (Fig. 29).

Paraproct (Fig. 31) with scale bases, almost bare, margin with approx. eight stout, pointed spines and bordered by few small spines; posterolateral extension with a few scale bases, minute spines along the margin.

Imagos: Unknown

Distribution and habitat.

We collected this species in only three different localities in close proximity, in extreme southwestern KSU close to the Yemen border. The larvae occur in medium-size streams with stony substrates (Figs 50, 51, 52). Larvae apparently prefer relatively fast flowing reaches. Larvae were even collected at the base of small waterfalls. Labiobaetis alahmadii  appeared to be an abundant species when the above ecological conditions are optimal. The new species was always sympatric with L. glaucus  .


This species is dedicated to the memory of Professor Ahmed Ziad Al Ahmadi, the well-known Syrian entomologist who passed away few months ago.