Madagocerum, Oláh & Johanson, 2011

Oláh, J. & Johanson, K., 2011, Description Of A New Endemic Genus Of Trichoptera From Madagascar (Odontoceridae), Acta Zoologica Academiae Scientiarum Hungaricae 57 (2), pp. 117-129 : 119-121

Madagocerum gen. n.

Type species: Madagocerum bhemi sp. n.

The genus somewhat resembles philorheithrid genera in the genitalia, particularly by the preanal appendages that are fused to the dorsum of segment IX without visible seam, and the 2 appendages are more or less fused basally. This unique condition occurs otherwise only in the 4 philorheithrid genera Aphilorheithrus MOSELY, 1936 , Psilopsyche ULMER, 1907 , Ramiheithrus NEBOISS, 1974 , Kosrheithrus MOSELY in MOSELY et KIMMINS, 1953, and partly also in Mystacopsyche SCHMID, 1955 .

Head characters relating this genus to the Odontoceridae are the absence of apicomesal nodule on the first maxillary palp segment, lack of pilifer on the frons; reduced Cu 2 in the forewings, convex forewing termen, reduced anal lobe at the forewing bases, absence of jugal lobe and jugal vein in the forewings; and the presence of only a single, large ovoid mesoscutellar setose wart.

Diagnosis – Madagocerum species are similar to species in Lannapsyche and Phraepsyche and unlike those in all other genera in the family by the presence of two pairs of pronotal, bulbous and compact setal warts instead of one pair. Madagocerum species are distinguished from those in Phraepsyche by the much longer forewing discoidal cell, the forewing nygma is located closer to the mid-length of fork II than to basis of fork II, the venation of the hind wings is more intact, and the coxopodites of the genitalia are much wider in lateral view. Madagocerum species are separated to those in Lannapsyche by the absence of M3+ 4 in the hind wings, and in genitalia by the presence of well-developed superior appendages and absence of setae posterodorsally on segment IX. Madagocerum species are easily distinguished from the Seychellean Leptodermatopteryx tenuis ULMER, 1910 by having narrower hind wings than forewings (opposite in L. tenuis ), long triangular forewing thyridium cell instead of lens-shaped and convex thyridium cell, absence of discoidal cell in the hind wings, and in the genitalia by the wider coxopodites in lateral view.

Description – Male (in alcohol).Body dark brown; forewings brown, without pattern (in alcohol).

Head: Ocelli absent. Tentorium slender, almost U-shaped in dorsal view; without dorsal arm, with small hump; anterior arms narrowing slightly anteriorly; posterior arms short, wide, ending in pair of large posterior tentorial pits; tentorial bridge slender, slightly arching; in lateral view anterior tentorial arms straight, produced into short, thin frontogenal septum; internal sclerotized fold not extending dorsad to circumantennal sclerite; internal fold of frontogenal septum visible on facial surface, forming thin frontogenal suture above anterior tentorial pits and clypeogenal suture below tentorial pits. Facial groove pattern dominated by surface grooves of thin frontogenal septum starting from anterior tentorial pits; frontogenal vertical groove running posteriorly and slightly laterally to ventral margin of rounded frontogenal compact setal warts. Clypeogenal vertical grooves located ventrally of anterior tentorial pits; weakly developed, running obliquely, slightly mesally near upper corner of labrum. Clypeolabral groove not visible. Line separating labrum and clypeus not visible. Clypeus with pair of medium-sized, rounded, compact setose warts. Subantennal groove present, running vertically between ocellar grooves and frontogenal compact setose warts, short, not reaching anterior margin of warts. Subocular grooves indiscernible. Vertex wider than long; epicranial groove complete, frontal branch indiscernible; coronal groove well pigmented, visible along entire length of vertex. Antennal sockets located on slightly elevate humps at antennal grooves. Occipito-postgenal grooves visible on vertex between occipital and postgenal setal warts. Postoccipital groove present, encircling foramen magnum, or occipital foramen; without postoccipital lobe. Labrum freely hanging, membranous, movable; ligulate structure without setae. Mandibles membranous, almost indiscernible; lacinia forming short, slender, mesad curving setose lobes. Pair of large, rounded, frontogenal compact setose warts dominating on face, immediately above small, rounded clypeogenal warts. Pair of rounded, small, clypeal mesal compact setose wart present below anterior tentorial pits and clypeogenal grooves. Anterior part of vertex with pair of rounded, elevated, medioantennal compact setal warts; vertexal lateroantennal compact setose warts absent; large vertexal medioocellar diffuse setose warts, or surfaces, present. Occipital compact setose warts forming largest setal vertexal structures, located obliquely, dominating on posterior surface of vertex. Broad postgenal compact warts curving along posterior section of ocular grooves. Maxillary palp formula I– II –IV–( III, V), segment I without apicomesal nodule or erect apical setae. Antennal scapes shorter than head. Each pedicel half as long as first segment of flagellum.

Pair of large, rounded frontogenal compact setose warts dominating on face, just above small, rounded clypeogenal warts; other warts visible on face is pair of round, small, clypeal mesal compact setose wart between, or below, anterior tentorial pits, and between clypeogenal grooves. Anterior area of vertex with pair of rounded, elevated, well-separated vertexal medioantennal compact setal warts. Vertexal lateroantennal compact setose warts absent. Vertexal medioocellar diffuse setose warts, or surface, large. Occipital compact setose warts representing largest setal structure on vertex. Wide postgenal compact warts curving along posterior section of ocular grooves. Maxillary palps five-segmented; maxillary palp formula I– II –IV–( III, V), first segments without nodule. Antennal scapes shorter than head. Pedicels half as long as first segment of flagellum.

Thorax: Pronotum with 2 pairs setal warts; both elevated; mesal pair large, circular, with straight-lined mesal margin, slightly separate mesally by deep, narrow depression or fissure; lateral pair small, longitudinally ovoid. Mesoscutum with pair of medium-sized, circular, compact setose warts in middle of segment, along median notal suture. Single, longitudinally ovoid, setose wart present at middle of mesoscutellum, sparsely covered by setae. Proepisternum with large, vertically elongated, ovoid, setose wart. Precoxale with large, nearly round setal wart. Large, compact, setal wart present anteriorly on each cervical sclerite; apparently forming sclerotized surface on membranous part of neck, anteriorly tangential with cervical sclerite. Lateral cervical sclerites forming narrow anterior arm articulating anteriorly to back of head with occipital condyle above posterior tentorial pits, fused to posterior cervical sclerites. Posterior cervical sclerite forming widening plate, rounded posteriorly, with dorsal sinus producing into elongate, filiform, apicodorsal corners; complex posterior arms reaching prothoracic episternum by posterior, round apex; articulating to weakly sclerotized anteromedian band of prothoracic eusternum by thin, ventral, intercervical sclerites fused to posterior sclerites. Dark structures of cervical sclerite complex visible on pale, membranous neck. Leg claws symmetrical; spur formula 244. Each foreleg with anterior spur half as long as posterior spur, covered by decumbent setae, posterior spur bare; both mid leg and hind leg with posterior spurs 1/3 as long as anterior spurs; all spurs with aciculate surface microsculpture; spurs of same colour as legs. Legs covered by thin, short, light brown, vestitural decumbent setae.

Wings: Forewing narrow, apically rounded; membrane light brown; termen slightly convex; basal lobe covered by microtrichia; jugum absent. Forewing forks I, II, III and V present; Sc running to R 1; R 1 running to R 2 before C, veins meeting at hypertrophied pterostigma; Cu2 apparently lacking in forewings; postanal vein present, running closely to posterior margin.

Male genitalia: Abdominal segment IX fused annularly, short, glabrous; anterior margin convex in lateral view, with mesally depressed lateral concavity conspicuous in dorsal view; posterior margin without pronounced apical lobe; antecosta and antecostal sutures on anterior margin of segment IX narrow. Intersegmental depression between segments IX and X very deep, stepwise; segment X sunk deep to upper 1/3 of segment IX. Segment X bilobed, straight, oriented posteriad. Apicoventral setose lobes forming setose apices. Apicodorsal setose lobes present at middle of segment; with scattered setae. Preanal appendages fused with tergum IX. Coxopodites robust; harpagones variously formed. Phallic apparatus with broad, ventrad directed, short basal part, and straight, horizontal apical part, small phallotremal sclerites almost indiscernible.

Etymology: Madago -, derived from Madagascar, and - cerum, from Greek keras, horn, antenna; name referring to the type locality.