Labiobaetis potamoticus 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

Labiobaetis potamoticus Gattolliat & Al Dhafer sp. n. Figs 1-8, 9-15, 16-19

Baetis balcanicus Müller-Liebenau & Soldán, 1981 in Thomas and Sartori 1989: 87.

Type material.

Holotype: Male larva (GBIFCH00521578): Saudi Arabia (AR44); Wadi Shahadan; 17°28'36"/ 42°42'50"; Alt. 190m; 13.XI.2012; Coll. J-L Gattolliat.

Paratypes: 4 larvae (GBIFCH00235716 + GBIFCH00235735 (Genetics)), 1 male imago (GBIFCH00235732 (Genetics)) + 3 larvae (KSU: GBIFCH00526192); same data as holotype.

42 larvae (GBIFCH00235729 + 3 slides GBIFCH00235758, GBIFCH00235733, GBIFCH00235760): Saudi Arabia (AR01); Al Jiwah, Thee Aine; 19°55'32"/ 41°26'17"; Alt. 752m; 13.X.2010; Coll. B. Kondratieff.

14 larvae (GBIFCH00235721): Saudi Arabia (AR20); Wadi Baqrah; 18°47'29"/ 41°56'19"; Alt. 490m; 13.III.2012; Coll. Al Dhafer, H. & Kondratieff, B.

5 larvae (GBIFCH00235722): Saudi Arabia (AR28); Thee Ain, Al-Baha; 19°55'46"/ 41°26'34"; Alt. 760m; 3.VI.2012; Coll. Al Dhafer, H. & Kondratieff, B.

2 larvae (GBIFCH00235714): Saudi Arabia (AR31); Thee Ain, Al-Baha; 19°55'46"/ 41°26'34"; Alt. 760m; 8.XI.2012; Coll. J-L Gattolliat.

58 larvae (GBIFCH00235706, GBIFCH00235728, GBIFCH00235717 + 2 slides GBIFCH00235749, GBIFCH00235759 + GBIFCH00517520 (Genetics), GBIFCH00517521 (Genetics)) + 11 larvae (KSU: GBIFCH00526173): Saudi Arabia (AR32); Wadi Elarj, near Adam; 20°27'11"/ 40°48'56"; Alt. 440m; 9.XI.2012; Coll. J-L Gattolliat.

23 larvae (GBIFCH00235726, GBIFCH00235719 + 3 slides GBIFCH00235753, GBIFCH00465152 (Genetics), GBIFCH00465155 (Genetics)) + 4 larvae (KSU: GBIFCH00526224): Saudi Arabia (AR43a); Wadi Shahadan; 17°28'36"/ 42°51'25"; Alt. 460m; 12.XI.2012; Coll. J-L Gattolliat.

3 larvae (KSU: GBIFCH00526237): Saudi Arabia (AR43b); Wadi Shahadan; 17°28'17"/ 42°51'14"; Alt. 455m; 12.XI.2012; Coll. J-L Gattolliat.

Additional material.

1 larva (on slide), Saudi Arabia, Wadi Buwah, 1340m, 20°47'N / 41°12'E, 20.IX.1980, Leg. W. Büttiker. Coll. Naturhistorisches Museum Basel, Switzerland. (Previously identified as Baetis balcanicus , det. A. Thomas).

Differential diagnosis.

Larva: Tergites I-X medium brown with peculiar pattern formed of six ecru dots (Fig. 19). Scape of antenna without distolateral process (Fig. 13). Segment II of the maxillary palp without a distomedial concavity (Fig. 7). Segment II of labial palp with a slender triangular distomedial projection (Fig. 8). Dorsal margin of femur with a few medium setae, not abundant proximally; ventral margin with abundant medium setae (Fig. 10). Dorsal margin of tibia almost bare (Fig. 9). Paraproct with numerous distal spines (Fig. 15). Male imago: Genitalia with inner margin of segments I and II without expansion; segment III almost globular (Fig. 18).

Description.

Larva.Length: fully grown female: Body 5.1-7.7 mm, cerci 3.6-4.0 mm, terminal filament 2.5-2.6 mm. Fully grown male: Body 5.0-5.3 mm, cerci 3.4-3.6 mm, terminal filament 2.5 mm.

Colouration (Fig. 19): Head almost uniformly brown with ecru vermiform marking on vertex and frons, border of sclerites yellow. Prothorax medium brown, lighter laterally; mesothorax medium brown with a central yellow dot and a transversal yellow stripe; metathorax medium brown. Legs: ecru except a brown central dot on femora; dorsal and ventral margin of femora brown, dorsal margin of tibiae and tarsi brown. Tergites I-X medium brown with peculiar pattern formed of six ecru dots sometimes fused. Abdominal sternites brown sometimes with four ecru dots. Cerci ecru brown getting progressively ecru towards apex.

Head: scape of antenna without distolateral process (Fig. 13).

Labrum (Fig. 1) rounded with a small anteromedial emargination, dorsally with a distolateral row of approx. eight feathered setae, without a submedian seta; short, thin, simple setae scattered on dorsal surface of labrum; distal margin bordered with feathered setae.

Right mandible (Fig. 2): 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 small pointed denticles (Fig. 3); margin between prostheca and mola slightly convex, smooth, without setae; tuft of setae at apex of mola absent.

Left mandible (Fig. 4): 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 (Fig. 5); margin between prostheca and mola slightly concave, without crenulations; tuft of setae at apex of mola absent.

Hypopharynx as illustrated in Fig. 6.

Maxilla (Fig. 7) 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, longer than galea-lacinia, segment II without distomedial concavity.

Labium (Fig. 8) with glossae shorter than paraglossae; glossae inner margin with two rows of approx. six long setae, apically with a few simple setae; paraglossae stout, apically flattened, with three rows of long simple setae; labial palp with segment I slender, quadrangular, shorter than segments II and III combined; segment II with a slender, elongated distomedial projection with few thin setae apically, on posterior side with a row of four long setae increasing in length; segment III subconical, inner margin apically slightly concave, with abundant scattered short thin setae and stouter setae.

Thorax: hind wing pads present.

Legs (Fig. 9): forefemur dorsally with a row of approx. eight medium-sized, apically rounded setae; apex with one medium stout seta and several short flattened setae; ventral margin with a poorly developed villopore and abundant, medium, stout setae (Fig. 10). Foretibia dorsally almost bare; ventrally with short setae, only slightly longer apically. Foretarsus almost bare dorsally; ventral margin with a row of pointed setae slightly increasing in length toward apex; tarsal claw (Fig. 11) with a single row of approx. twelve pointed teeth; without subapical setae. Middle and hind legs similar to foreleg but with reduced setation.

Abdomen: tergites (Fig. 14) shagreened with numerous scales and scale bases, with a few setae; posterior margin with triangular spination as long as broad. Sternites with scales and scale bases; posterior margin smooth, without spines.

Gills present on abdominal segments I–VII (Fig. 12), poorly serrated, tracheation brown, with abundant ramifications.

Paraproct (Fig. 15) with scale bases and a few setae, margin with numerous small triangular spines regular in size; posterolateral extension with a few scale bases, spines along the margin of the same size as those of the paraproct.

Male imago

Length. Body 4.8 mm; forewing 4.4 mm; hindwing 0.8 mm.

Colouration: head brown; antenna ecru except base of scape and pedicel brown. Facetted surface of turbinate eyes dark orange brown, shaft orange brown, lighter apically (Fig. 16). Thorax yellowish brown with margin of sclerites generally dark brown. Legs: yellowish without marks or pattern. Wings hyaline, hyaline venation. Abdomen: tergites I to X ecru without pattern. Sternites I to IX ecru. Cerci ecru. Genitalia (Fig. 18) ecru except inner margin of segment I medium brown.

Forewing: pterostigma with approx. two cross-veins not reaching subcostal vein; double intercalary veins shorter than distance between corresponding main veins.

Hindwing (Fig. 17) without costal spur; two longitudinal veins almost reaching margin, none of them bifurcated, without incomplete veinlets between main longitudinal veins.

Genitalia (Fig. 18): basal segment with inner margin not expanded apically; segments I and II almost completely fused; constriction at basis of segment II; segment III globular.

Distribution and habitat.

Labiobaetis potamoticus appears to be the most widespread species of Labiobaetis in KSU. It colonizes aquatic vegetation in still reaches of small to medium-sized streams with a sandy substrate (Figs 48, 52). This species was also collected in a secondary channel with Typha sp. (Fig. 49). This species seems less rheophilic than the two following taxa.

Etymology.

The specific name potamic- was given in reference to the ecological preferences of the species for still and standing water.