Smicridea (Rhyacophylax) sanctorum, Gibon & Sganga, 2019

Gibon, François-Marie & Sganga, Julieta V., 2019, The genera Smicridea McLachlan and Chimarra Stephens in French Guiana (Trichoptera: Hydropsychidae, Philopotamidae), Zootaxa 4604 (1), pp. 183-190 : 184-185

Smicridea (Rhyacophylax) sanctorum sp. n.

( Figures 1–10 )

Type material. Holotype. Male (disarticulated and mounted on slides), FRENCH GUIANA, Crique Toussaint, 5°20’13.50’’N, 52°59’4.70’’, 34 m a.s.l., 28.ix.2010, F.- M. Gibon leg. ( CBGP) . Paratypes. 6 males (3 on slides, 3 in alcohol), same label data as holotype ( CBGP) .

Diagnosis. Smicridea (R.) sanctorum sp. n. is closely similar to S. (R.) dentisserrata Albino, Pes & Hamada 2011 . In the two species, abdominal segments IX and X are fused in such a way that it is not easy to determine the origin of the observed structures. The tergum IX is positioned dorsally with respect to tergum X ( Fig. 1 ), the whole is maintained by a sclerotized Y structure, composed of three branches, ventral, dorsal (Ydo, Fig. 1 ) and distal (Ydi, Fig. 1 ). The ventral branch arises from the ventral base of sternum IX; the distal branch is the lateroventral margin of tergum X; the dorsal branch may be an extension of one of the two previous. The apex of the distal branch generally corresponds to the distal end of tergum X but in S. dentisserrata and in S. sanctorum sp. n., they are clearly distinct, the distal branch is straight in the new species ( Fig. 2 ) and curved inwards in S. dentisserrata (Fig. 22 in Albino et al. 2011). In the two species, the apex of tergum X is mesally divided, each hemitergite is truncated posteriorly in S. dentisserrata (Fig. 22 in Albino et al. 2011) and rounded in the new species ( Fig. 2 ). The main diagnostic character is the size and distribution of the spines of the distal branch; they are larger and grouped apically and preapically in the new species, giving to the distal branch the appearance of a mace; they are distributed nearly all along the ventral edge in S. dentisserrata , giving it the appearance of a saw (which is the etymology of the species name). Small but clear morphological differences are also remarkable at the phallic apparatus. Albino et al. (2011) described «2 apico-ventral paramere spines», one anterior, ending in 7 points and one posterior, broad and truncate (Figs. 24, 25 in Albino et al. 2011). In the new species the apico-ventral margin of the phallotheca is elongated, curved dorsad and enlarged, two small spines are inserted latero-ventrally but are hardly visible in dorsal view. As this ventral projection of phallotheca is truncate, the dorsal view is quite similar to that of the posterior spine of S. dentisserrata (Fig. 24 in Albino et al. 2011). On the same dorsal view, the apex of the phallotheca is U-shaped whereas it is smoothly concave in the new species.

Description. Adult male. General coloration (in alcohol) brown. Interocular distance 0.14 mm. Maxillary palp with relative lengths of segments from base: 1, 1.5, 2.5, 2, 7.5 ( Fig. 2 ). Wing color pattern of forewings brown, each with perpendicular clear strip at maximum width; hind wing light brown ( Fig. 9 ). Length of each forewing 3.80 mm, hind wing 2.90 mm. Anterolateral glandular processes of sternum V long and slender composed of short base, rigid and slightly bent, and distal part, thinner, longer, with wrinkled appearance ( Fig. 6 ).

Male genitalia. Segment IX, in lateral view, with Y-shaped internal sclerotization; anterolateral margins concave, anteromesal margins each produced into blunt lobe directed upwards ( Fig. 1 ); in dorsal view, tergum subtriangular, posterior margin projected into blunt mesal lobe covered with small spines ( Fig. 2 ). Tergum X laterally expanded; in dorsal view divided apicomesally; each hemitergite rounded posteriorly and slightly notched posteromesally, dorsal setal wart slightly oblique and bearing four long setae, and, apically, three tiny setae; ventrolateral margins (distal branch of the Y structure) sclerotized, posteriorly enlarged and covered of spines.

Inferior appendages each two-articulated, setose, basal article long with distal region slightly bent inward; apical article thinner and shorter (less than half as long as basal article) ( Fig. 3 ). Phallic apparatus with tubular phallobase, its basal section slightly enlarged, forming angle of about 120° with distal section; dorsal margin with large, dorsal periphallic cap bearing small spines directed posterad ( Fig. 10 ); apicoventral margin of phallotheca elongated, curved dorsad and enlarged with two small spines inserted lateroventrally on each side (paramere spines of Albino et al. 2011); apical portion of ejaculatory duct sclerotized, long and sinuous in lateral view, with two short and sclerotized dorsolateral processes ( Figs. 8, 9 ).

Etymology. The name is a reference to the river where the new species was collected, the Crique Toussaint (French for all the saints).

Figures

FIGURE 3. Smicridea (Rhyacophylax) sanctorum n. sp., right wings, dorsal. Scale bar: 1 mm.

FIGURES 1–2. Smicridea (Rhyacophylax) sanctorum n. sp.: 1, maxillary palp; 2, glandular process of sternum V. Scale bar: 0.25 mm.

FIGURES 4–6. Smicridea (Rhyacophylax) sanctorum n. sp., male genitalia: 4, left lateral; 5, terga IX and X, dorsal; 6, left inferior appendage, dorsal. Scale bar: 0.25 mm. i.a. = inferior appendage, p.a. = phallic apparatus, s.IX = sternum IX, t.IX = tergum IX, t.X = tergum X, Ydi. = distal branch of the Y structure, Ydo. = dorsal branch of the Y structure.

FIGURES 7–10. Smicridea (Rhyacophylax) sanctorum n. sp., phallic apparatus: 7, dorsal; 8, apex of the phallic apparatus, dorsal; 9, apex of the phallic apparatus, left lateral; 10, spines of the dorsal cap, dorsal. d.c. = dorsal cap, l.p. = lateral process of the phallicata, l.sp. = lateroventral spines, v.p. = ventral projection of the phallotheca.