Leptonema amplifurcatum, Dumas, Leandro Lourenço & Nessimian, Jorge Luiz, 2009

Dumas, Leandro Lourenço & Nessimian, Jorge Luiz, 2009, A new species of Leptonema Guérin (Trichoptera: Hydropsychidae) from southeastern Brazil, Zootaxa 2245, pp. 65-68 : 65-68

Leptonema amplifurcatum sp. nov.

Figs. 1–9

Leptonema amplifurcatum sp. nov. is a member of the L. speciosum Group, as defined by Flint et al. (1987). It is closely related to L. bifurcatum Flint, McAlpine & Ross, 1987 and L. bifurcatodes Flint, 2008 , differing principally in the presence of processes f on the male phallus (not illustrated and not mentioned in the description of the other 2 species) and by the shape and size of processes g on the phallus. The new species has processes g forked, like those of L. bifurcatum and L. bifurcatodes , but the fork is extremely large and wide, U-shaped, resembling a spanner. In the other 2 species, this fork is proportionately shorter and not enlarged. The new species is also distinguished by the apex of the phallus and the shape of the fused processes b-c. In L. bifurcatum these processes are upturned and bifid apically, whereas in L. bifurcatodes they are tapered apically and each has a pair of apicomesal points. In L. amplifurcatum sp. nov., processes b-c are longer, deeply bifid apically and recurved cephalad. An additional character difference, observed in all individuals, is the presence of a small basolateral projection on the left side of process b-c, near apex.

Some asymmetry and small morphological differences were observed in the type series, especially in processes g. In some individuals, the processes vary between the right and left sides. The subapical projection may bear 1 or 2 minute spines ( Fig. 9 A, B) or even be bifid ( Fig. 9 C). Processes f may also be asymmetrical, with 2 accessory spines sometimes present on the left side (as in the holotype specimen).

Description. Adult male ( Figs. 1–9 ): Length of forewing: 14.0–17.0 mm (n=5). Head, antennae, maxillary palps and legs yellowish, stramineous in alcohol. Wings light brown, without maculae.

Head ( Fig. 1 ): Malar space narrow, about 1/5th height of eye. Frontal setal wart, between the antennal bases; one pair of small antennal setal warts not clearly delimited; one pair of large, subtriangular posterior setal warts behind eyes; one pair of slender setal warts, bearing long dark setae on postgenal area. Maxillary palps 5-segmented, long, setose; segment III slightly longer than segment II; segment V extremely long, about the length of all other segments together ( Fig. 1 ).

Thorax: Legs long, with fine yellowish setae; tibial spur formula 2-4-4. Forewing with brown setae along costal and subcostal area, extending from base to near apex; forks I-V present; discal cell short, broad. Hind wing shorter, with forks I, II, III and V present.

Abdomen ( Fig. 2 ): Sternum II with a small mesal suture; sternum V with processes large, ovoid, set slightly Male genitalia ( Figs. 3–9 ): Segment IX, in lateral view, short, tall ( Fig. 3 ); in dorsal view with large V-shaped keel ( Fig. 4 ). Segment X with wart a large, rounded; warts b and c absent; lateral lobes rounded apically, in dorsal view, truncate in lateral view, bearing short setae on lateral margins; mesal lobes, in dorsal view, elongate, subacute, narrowly separated ( Figs. 3, 4 ). Inferior appendages 2-segmented, basal segment longer than apical segment, wider distally, with dorsal tuft of long setae on distal portion; apical segment slender, slightly larger at base, nearly 2/3rds length of basal segment, with short setae on inner margin ( Fig. 5 ). Phallus long, tubular, with base very broad ( Fig. 3 ); midsection bearing small lateral spines anterior and posterior of processes f; processes f well developed, spiniform in lateral view ( Fig. 6 ), dorsally forming pair of stout spines, left side with 2 small spines, of which more mesal spine shorter than lateral one ( Fig. 7 ); apical section bearing quadrangular processes a, each with apex truncate ( Figs. 6, 7 ); processes g large, recurved cephalad, each with robust tip and, U-shaped, upturned fork (with minute subapical spine in right fork) ( Figs. 6, 7 ); processes b and c each fused to form single apicomesal lobe, broadened subapically and recurved cephalad apically, forming pair of long spines with small basolateral point on left side only ( Figs. 6, 7, 8 ). Phallotremal sclerite well developed, heavily sclerotized, dorsally with blackish forked points, in front of processes a ( Fig. 7 ).

Female: Length of forewing: 15.0–18.0 mm (n=5). Color and structure similar to male. Genitalia typical for the genus.

Holotype male: BRAZIL, Rio de Janeiro, Mangaratiba: Reserva Ecológica Rio das Pedras, Rio Grande, 22°59’31.20’’S 44°06’18.00’’W, 96 m, 31.v.2003, J.L. Nessimian & N. Ferreira Jr. leg. ( DZRJ 1705).

Paratypes: BRAZIL, Rio de Janeiro, Mangaratiba: Reserva Ecológica Rio das Pedras, Rio Grande, 22°59’31.20’’S 44°06’18.00’’W, 96 m, 31.v.2003, J.L. Nessimian & N. Ferreira Jr. leg., 1 male ( DZRJ 1706); Reserva Ecológica Rio das Pedras, Rio das Borboletas, 22°59’31.24’’S 44°06’03.52’’W, 42 m, 09.v.2003, J.L. Nessimian leg., 1 male ( DZRJ 1707); same locality and data, 1 male ( DZRJ 1708); Reserva Ecológica Rio das Pedras, Rio Grande, 22°59’30.35’’S 44°06’17.16’’W, 86 m, 21.v.2005, L.L. Dumas & A.P.M. Santos leg., 1 male ( DZRJ 1709); Reserva Ecológica Rio das Pedras, Rio Grande, 22°59’31.20’’S 44°06’18.00’’W, 96 m, 06.v.2007, A.P.M. Santos leg., 1 male ( MZSP); Reserva Ecológica Rio das Pedras, Rio das Borboletas, 22°59’31.24’’S 44°06’03.52’’W, 42 m, 06.v.2007, A.P.M. Santos leg., 1 male ( DZRJ 1711); same locality, 09.v.2003, J.L. Nessimian leg., 10 females ( DZRJ 1712); same locality, 06.v.2007, A.P.M. Santos leg., 2 females ( DZRJ 1713); same locality and data, 1 female ( MZSP).

Etymology. This species is named amplifurcatum in reference to processes g of the male phallus, each of which has a wide apical fork. It is derived from the Latin words amplus (“wide” or “large”) and furcata (“fork”).

Distribution. Southeastern Brazil (Rio de Janeiro state).

Figures

FIGURES 1 – 5. Leptonema amplifurcatum sp. nov., male. 1. Maxillary palp, lateral view; 2. abdominal sternum V, ventral view; 3. genitalia, left lateral view; 4. genitalia, dorsal view; 5. right inferior appendage, ventral view.

FIGURES 6 – 9. Leptonema amplifurcatum sp. nov., male. 6. Phallus, left lateral view; 7. phallus, dorsal view; 8. phallus, ventral view; 9 A-C. variations of left process g of phallus, left lateral view.