Strepsicrates gattii Vargas-Ortiz & Vargas, 2018

Vargas-Ortiz, Marcelo & Vargas, Héctor A., 2018, A new species of Strepsicrates Meyrick (Lepidoptera: Tortricidae) from the Atacama Desert of northern Chile previously misidentified as S. smithiana Walsingham, Zootaxa 4370 (5), pp. 569-579 : 571-577

Strepsicrates gattii Vargas-Ortiz & Vargas , sp. n.

Figs. 1–6

Strepsicrates smithiana ; misidentification ( Vargas 2012)

Type material. MALE HOLOTYPE, CHILE: Lluta, Arica , Chile, June 2010, H.A. Vargas coll., reared from larva on Morella pavonis , May 2010 ( MNNC) . PARATYPES, CHILE: two males, two females, same data as holotype ( MNNC); two males, two females, same data as holotype; one male, Lluta, Arica, Chile, Sep 2010, H.A. Vargas coll., reared from larva on Morella pavonis , August 2010; two females, Azapa, Arica, Chile, Oct 2011, H.A. Vargas coll., reared from larva on Morella pavonis, Oct 2011 ; one male, two females, Azapa, Arica, Chile, Nov 2011, H.A. Vargas coll., reared from larva on Morella pavonis, Oct 2010 ; two females, Codpa, Arica, Chile, Feb 2011, H.A. Vargas coll., reared from larva on Morella pavonis, Jan 2011 ( IDEA).

Diagnosis. The male genitalia of S. gattii are remarkably similar to those of the Neotropical S. smithiana ; however, the two species can be separated based on differences in forewing pattern and male and female genitalia. The forewing of S. gattii is mostly uniformly reddish brown, whereas the forewing of S. smithiana has dark brown patches with a cream white stripe on the posterior margin. The valva of the male genitalia of S. gattii is slightly narrower in the middle than in S. smithiana , with a more elongated appearance in S. gattii ; furthermore, the ventral lobe of the cucullus of S. gattii is wider than the spine, whereas the two structures have similar width in S. smithiana . The female genitalia provide the best features for separating the two species, as the posterior margin of the lamella post-vaginalis almost coincides with the two posterior projections of sternum VII in S. gattii , whereas the posterior margin of the lamella post-vaginalis is displaced forward in S. smithiana ; also, the ductus bursae is coiled starting at the ostium bursae in S. gattii , whereas the basal portion of the ductus bursae of S. smithiana is widened.

Description. Male ( Fig. 1A ). Head: Scales of vertex reddish brown, elongate, projected upward; scales of front mostly yellowish gray, short, appressed, a few scattered dark brown scales. Compound eye dark brown. Antenna filiform yellowish gray, with notch involving flagellomeres 7–9. Labial palpus forward projected, slightly upturned; first segment short, yellowish white; second segment elongate, about 1.3 times diameter of compound eye, laterally mostly covered by elongate reddish brown scales intermixed with light gray scales, medial surface covered by yellowish white scales; third segment covered by appressed light brown scales, partially hidden by apex of scales of second segment. Thorax: Dorsally covered by reddish brown, posteriorly projecting scales; laterally yellowish white. Foreleg coxa and trochanter yellowish white with a few scattered grayish brown scales; femur, tibia (including epiphysis), and tarsus grayish brown with a few scattered yellowish white scales. Midleg similar to foreleg, but without tibial epiphysis and with pair of yellowish white tibial spurs. Hindleg completely yellowish white, including two pairs of tibial spurs. Forewing maximum length 8.1 mm.; reddish brown near costal margin, yellowish gray near posterior margin; a few scattered dark brown scales, mostly on discal cell; costal fold in basal half of costal margin. Hindwing creamy white, with yellowish gray scales near apex; fringe creamy white. Abdomen: Uniformly yellowish gray. Segment VIII modified: tergum ( Fig. 1G ) as a narrow stripe widened at anterior and posterior margins; sternum ( Fig. 1H ) with posterior part widened and a wide excavation at middle of posterior margin. Male genitalia ( Fig. 1C ; 1E–1H) with tegumen narrow, slightly widened dorsally. Uncus reduced to a small "hump". Socius broad and short. Gnathos lightly sclerotized, widened apically. Saccus narrow. Juxta triangular. Valvae symmetrical, narrow, elongate; costal margin weakly concave at middle; distal margin broadly rounded; cucullus with digitiform ventral lobe and spine ( Fig. 1F ). Phallus about half length of valva; ventral margin widely concave; vesica with group of 3–4 spindle-shaped deciduous cornuti ( Fig. 1E ).

Female. Head and Thorax: Similar to that of male, but antennae without notch on flagellum, forewings without costal fold, and abdominal segment VIII not modified as in male. Abdomen: Female genitalia ( Fig. 1B ; 1D) with papillae anales broad, with hair-like setae. Anterior and posterior apophyses similar in length, slightly longer than papillae anales. Ostium bursae near sharply excavated posterior margin of sternum VII. Lamella postvaginalis ( Fig. 1D ) a transverse, well-sclerotized stripe, laterally continuous with sternum VII; posterior margin of lamella postvaginalis nearly coinciding with two posterior projections of sternum VII. Ductus bursae sclerotized basally, membranous distally. Corpus bursae subspherical, membranous, reticulated, slightly depressed dorso-ventrally.

Immature stages. Larva ( Fig. 2–3 ). Last instar (n = 6). Semiprognathous, maximum length 12 mm. Head width 0.9–1.0 mm. Frontoclypeous triangular ( Fig 2A ). Ecdysial line sinuous, close to adfrontal suture. Six circular stemmata laterally ( Fig 2B ); stemmata 1–5 arranged in a semicircle, stemma 6 approximately at midpoint between stemmata 1 and 5; head capsule ventrally projected close to stemma 5. Labrum bilobed ( Fig. 3A ); six setae on the medial area, three setae on each lateral area; three pairs of teeth on internal surface. Mandible ( Fig. 3B ) dark brown with five distal teeth. Thorax and abdomen grayish green; prothoracic dorsal and anal shields light brown; circular spiracle ( Fig. 3G ) laterally on T1, A1–8; thoracic legs light brown, tarsal integument sculptured by a few short spine-like ornamentations, a curved claw ( Fig. 3F ) at apex; prolegs on A3–6 and A10, crochets in biordinal circles on A3–6 ( Fig. 3C ), in mesoseries on A10 ( Fig. 3D ). Anal comb ( Fig. 3E ) with 6–7 spines present on A10. Chaetotaxy as shown in Fig. 2 .

Pupa ( Fig. 4 ). Male (n = 5). Yellowish brown ( Fig. 4C ), maximum length 6.5 mm ( Fig. 4A–C ; 4E). Vertex slightly projected forward between bases of antennae; one pair of setae laterally on dorsal surface. Front broad with two pairs of setae close to labrum. Apex of antenna slightly exceeding apex of mesothoracic legs. Labial palpi about one-half length of haustellum. Haustellum about one-half length of mesothoracic legs. Apex of metathoracic legs slightly exceeding apex of antenna. Circular spiracle laterally on A2–8 ( Figs. 4B–C ). Prothoracic segment with one pair of laterodorsal setae ( Fig. 4B ). Mesothoracic and metathoracic segments present two pair of dorsal setae. Segment A1 with one pair of dorsal setae. Segments A2–8 with two parallel transverse rows of spines (fig.

4E) on dorsal surface; spines of anterior row greater than spines of posterior row; two pairs of dorsal setae, one near anterior margin and one near posterior margin; four pair of lateral setae, one dorsal to spiracle, two ventral to spiracle and one near posterior margin. Segments A5–7 with four pairs of ventral setae. Segment A8 with three pairs of ventral setae. Segment A9 with three pairs of lateral setae and two pairs of ventral setae; one transverse row of spines near posterior dorsal margin; genital scar ventrally with a short longitudinal line and two circles laterally. Segment A10 with one dorsal transverse row of spines near posterior margin; anal cleft ventrally; one pair of short setae anterior to anal cleft; three pairs of long setae with curved tip, one pair anterolateral to anal cleft, two pairs subapical.

Female ( Fig. 4D ) (n = 5). Similar to male, but genital scar on A8–9; anterior margin of A8 and anterior margin of A9 projected to genital scar; anterior margin of A10 projected to the anal cleft. Segments A7–8 with two pairs of ventral setae. Segment A9 with one pair of ventral setae.

Etymology. The name of the species is dedicated to the great Eduardo Gatti for his outstanding contribution to Chilean popular music.

Host plant ( Fig. 5 ). Morella pavonis is the only host plant known for S. gattii . This tree is the only native species of the family Myricaceae in Chile (Muñoz-Pizarro 1966). The geographic range of M. pavonis is restricted to northern Chile and southern Peru ( Luebert 2004). Exotic guava and eucalyptus trees, which are the only other representatives of Myricaceae and Myrtaceae , respectively, in the study area, were also surveyed for larvae of S. gattii without success, suggesting that this is a monophagous species.

Distribution. Strepsicrates gattii is known only from three transverse valleys of the Atacama Desert of northern Chile: Azapa, Codpa, and Lluta.

Molecular analysis ( Fig. 6 ). Two sequences of 658 bp of the DNA barcode fragment of S. gattii were obtained, each of which represented a different haplotype due to the presence of eight variable sites. The nucleotide frequencies (%) were T=37.8, C=16.5, A=31.2, and G=14.5. The divergence between the two haplotypes of S. gattii was 1.2% (K2P), whereas the divergence with the other congeneric species included in the phylogenetic analysis ranged from 4.9% (with " Strepsicrates Brown 25") to 8.7% (with S. infensa ). The alignment for the phylogenetic analysis was composed of 14 DNA barcode sequences of 658 bp with 179 variable sites, 118 of which were parsimony informative. The two sequences of S. gattii were clustered as a well supported clade that was sister to S. macropetana with 75% posterior probability. However, S. macropetana is an Australian species morphologically different of S. gattii . All the sequences of Strepsicrates were clustered with 100% posterior probability, and the interspecific relationships were in general well supported.

Figures

FIGURE 2. Last instar of Strepsicrates gattii. A) Head in frontal view; B) Head in lateral view; C) Thorax and abdomen in lateral view; Scale bars: 250 µm (A, B), 400 µm (C).

FIGURE 3. Morphological details of the last instar of Strepsicrates gattii. A) Labrum; B) Mandible; C) Crochets of A6; D) Crochets of A10; E) Anal comb; F) Tarsal claw; G) Spiracle of A3. Scale bars: 60, 100, 100, 80, 50, 20, 40 µm (A, B, C, D, E, F, G, respectively).

FIGURE 4. Pupa of Strepsicrates gattii. A) Male in ventral view; B) Male in dorsal view; C) Male in lateral view; D) Female terminalia in ventral view; E) Detail of B. Scale bar:800 µm.

FIGURE 5. Natural history of Strepsicrates gattii. A) Habitat in the type locality, the Lluta Valley; B) The host plant Morella pavonis; C) Typical aspect of a branch of M. pavonis; D) Apex of a branch of M. pavonis damaged by larvae of S. gattii; E) Detail of leaves tied by the larvae of S. gattii using silk threads (empty triangles). Scale bars: 2, 2, 0.5 cm (C, D, E, respectively).

FIGURE1. Adultof Strepsicrates gattii. A) Malein dorsal view;B)Female genitalia;C) Male genitalia;D) Detail of rectangle in Fig. B; E) Cornuti; F) Apex of the valva showing the ventral lobe and spine-like projection; G) Tergum VIII; H) Sternum VIII. Scale bars: 2 mm (A), 300, 300, 100, 70, 120, 200, 200 µm (B, C, D, E, F, G, H, respectively).

FIGURE6. Bayesiantree of thesequences ofthe DNA barcodefragment (658 bp) of the cytochromec oxidase subunitI (COI) gene of Strepsicrates gattii and congeneric species.