Palaeomystella tavaresi Becker & Moreira

Luz, Fernando A., Goncalves, Gislene L., Moreira, Gilson R. P. & Becker, Vitor O., 2014, Three new cecidogenous species of Palaeomystella Fletcher (Lepidoptera, Momphidae) from the Brazilian Atlantic Rain Forest, ZooKeys 433, pp. 97-127 : 109-116

Taxon classification Animalia Lepidoptera Momphidae

Palaeomystella tavaresi Becker & Moreira sp. n. Figs 1 E–F, 8-10, 11 G–I, 12 G–I

Walshia sp. Lima 1945: 303-305, figs 180, 183, 184, misidentification.

Diagnosis.

Closest to Palaeomystella rosaemariae , sharing with this species a pronounced palmate costa of the valve and a bladelike signa. As already mentioned, these characteristics differentiate them from all other species of Palaeomystella except Palaeomystella oligophaga . This species, however, has the forewings with R4-R5 fused and the hindwing with M1 and M2 stalked from the remnant chorda of the cell ( Becker and Adamski 2008). Palaeomystella tavaresi differs from Palaeomystella rosaemariae by having: 1) adults with body covered with pale-brown scales tipped with brown, and brown scales; 2) males with latero-anterior margin of eighth sternum anteriorly expanded medially into a stout, rounded lobe; valva with distal portion of costa wider; juxta longer than wide, anteriorly convex; 3) females with signa having inward projections shorter, straight and stout; 4) pupa with cremaster slightly bifurcated and posteriorly directed, with a latero-apically located pair of blunt spines; 5) galls of rosette type, induced on apical/terminal buds of Tibouchina fissinervia shoots, causing growth of clustered short leaves with a cylindrical gall chamber.

Description.

Adult (Figs 1 E–F). Sexes similar, forewing length 7.02 to 9.23 mm (n = 8). Head: Frons pale brown; vertex with pale-brown scales tipped with brown (Fig. 1F); labial palpus pale brown, basal segments angled laterally, terminal segment slightly angled upward; antennae brown; proboscis yellowish brown. Thorax: Tegula and mesonotum (Fig. 1F) with brown scales tipped with dark brown, posterior scales paler brown; fore and midlegs dark brown; hindlegs pale brown, tibia and tarsus with intermixed dark-brown scales. Forewings (Figs 1E, 8A): lanceolate, with 13 veins; L/W index ~ 4.4; dorsally covered with brown scales, intermixed with dark-brown scales tipped with black, and pale-brown scales; a narrow, ill-defined, dark-brown streak bisects the wing longitudinally from base to a brown, subapical, crescentic marking, edged distally with dark-gray scales; 3 raised scale tufts located posterior to cubitus, in anal area, in line with midcell, and near tornal area, respectively; fringes pale brown; ventral side most uniformly covered with dark-brown scales; discal cell closed, ~ 0.7 × length of forewing; ending near 1/5 wing margin; Sc ending ca. 1/3 anterior margin; R 5-branched; R1 ending near 1/4 of wing margin; R4 and R5 stalked ca. 1/2 distance from cell apex; M 3-branched; CuA 2-branched; CuP weak proximally and not stalked, with 1A+2A that is well developed, extending more than half length of posterior margin. Hindwing (Figs 1E, 8A): strongly lanceolate, with 9 veins; L/W index ~ 5.4, ~ 0.84 forewing in length; scales light brown on both sides; fringes pale brown; frenulum a single acanthus on male, with two parallel-sided acanthi in female. Sc+R1 ending ca. 1/2 anterior margin; Rs ending near end of anterior margin; M 3-branched, with M1 and M2 stalked near Rs; CuA 2-branched; CuP weakly sclerotized, ending at 1/2 posterior margin; 1A+2A well developed, ending near basis of posterior margin. Abdomen (not illustrated): scales pale brown intermixed with gray scales, with transverse irregular rows of spiniform setae on terga 2-7 in both sexes. Eighth sternum (Fig. 8C) expanded anteromedially into a stout, rounded lobe, associated with a subtrapezoidal sternite.

Male genitalia (Figs 8B, D–F, H). Uncus narrow, separated from tegumen by a narrow membranous area, laterally setose (Figs 8F, H); tegumen narrow; vinculum widened ventrally; transtilla a short, flat fig; aedeagus tubiform, curved ventrally, short (2 × longer than wide), slightly wider basally (Figs 8 E–F); vesica bearing several stout cornuti; juxta (Fig. 8D) attached to distal portion of aedeagus (Fig. 8E), as long as wide, with convex basal margin and pointed distally; valva (Fig. 8B) covered by several long setae, divided near 1/3 from the basis, with sacculus spatulate, tapering distad, and costa long, palmate, gradually constricted basad.

Female genitalia (Figs 8G, I–J). Papillae anales connected dorsally, setose (Figs 8 I–J); anterior apophyses similar in length to posterior, slightly curved apophyses; sterigma divided into a bandlike tergum and a distally bilobed sternum, deeply and narrowly emarginate medially; ostium bursae of small size, wider than long; ductus bursae membranous, longer than corpus bursae, with ductus seminalis inserted medially; corpus bursae an elongate sac, bearing two stout, straight, bladelike signa connected to crescentic figs located in the wall (Figs 8G, J).

Type material.

Holotype ♂: Brazil: Reserva Serra Bonita, 15°23'30"S, 39°33'57"W, 832 m, Camacan, BA, Brazil. Adults preserved dried and pinned, reared from galls induced on Tibouchina fissinervia (Schrank & Mart. ex DC.) Cogn. ( Melastomataceae ) by G.R.P. Moreira, 15-21.X.2013, LMCI 230-05, donated to DZUP (29.415). Paratypes: same data, 17-23.II.2013, LMCI 209; 1♂ (LMCI 209-31), 1♀ (LMCI 230-20), donated to DZUP (29.416 and 29.417, respectively); 1♂ (LMCI 230-06), 2♀ (LMCI 230-09 and 22) donated to VOB.

Other specimens examined.

Adults dried and pinned, collected in light traps at the type locality, deposited in VOB: 1♂ (VOB 144730), -.VIII.2009, by F.L. Santos; 1♂ (VOB 146783, with genitalia mounted on slide), -.IX.2010, by V.O. Becker. Additional specimens, with the same collection data as the type material, deposited in LMCI: adults dried and pinned, 6♂ (LMCI 230-07, 15, 16, 17 and 21; LMCI 230-08, with genitalia in glycerin GRPM 50-57) and 6♀ (LMCI 230-10, 11, 12, 18 and 19; LMCI 230-23, with genitalia in glycerin GRPM 50-58). Slide preparations, mounted in Canada balsam: adults, 1♂ (GRPM 50-54), 1♀ (GRPM 50-55); wings, 1♂ (GRPM 50-53); larvae, 2 last instars (GRPM 50-56). Immature stages, fixed in Kahle-Dietrich’s fluid and preserved in 70% EtOH: 5 last-instar larvae (LCMI 209-13 and 14, and 230-2); 6 pupae (LMCI 209-7, 11, 18, and 230-1); 12 dissected galls (LMCI 209-21 and 22, 230-3 and 4). In tissue collection, 6 larvae (LMCI 209-06) fixed and preserved in 100% EtOH, at -20°C.

Immature stages.

Last larval instar (Fig. 6), 7.28 to 11.7 mm (n = 4). Cecidogenous, endophyllous, semiprognathous and tissue-feeder. Body subcylindrical, creamy white, changing to light yellow before pupation, with setae well developed. Head (Figs 9A, C–D): uniform dark brown, with two conspicuous unpigmented, irregularly shaped areas along ecdysial line; smooth, with shallow ridges; labrum shallowly notched; frons higher than wide, extending ca. 3/4 epicranial notch; six stemmata arranged in C-shaped configuration. Chaetotaxy (Fig. 9A): A-group trisetose; L-group unisetose; P-group bisetose; MD trisetose; C-group bisetose; F-group unisetose; AF-group bisetose; S-group trisetose; SS-group trisetose. A1, A3, P1 and S2 about equal in length, longest setae on head; C1, C2, F1, A2, AF2, L1 intermediate in length; AF1 absent; MD1-3 very reduced and aligned with each other. Antenna two-segmented. Mandibles broad, with four teeth and one seta on the outer surface; labium broad, with two-segmented palpus, the distal segment minute; spinneret parallel-sided; maxilla prominent. Thorax and Abdomen (Figs 9 B–D): Prothoracic shield and anal fig irregularly marked with dark brown. Thoracic legs light brown. Prolegs on A3-A6 and A10 of equal size; crochets in a circle, uniserial and uniordinal. Thorax chaetotaxy: T1 with D-group bisetose, both located on the dorsal shield, D1 shorter than D2; XD-group bisetose, setae similar in length and both located on the dorsal shield; SD bisetose, located laterally on the dorsal shield; L group bisetose, L1 longer than L2; SV-group bisetose, posteroventral to L2, SV1 slightly longer than SV2; V-group unisetose. T2 and T3 with D- and SD-groups bisetose, median-transversely aligned; D2 and SD1 similar in length, and longer than D1 and SD2 respectively; L trisetose, L3 posterior to L1 andL2, similar in length to L1; SV unisetose; V unisetose. Abdomen chaetotaxy: D-group bisetose; A1-9 with D2 slightly longer than D1, and A10 with D1 longer than D2; SD-group bisetose, A1-7 with SD1 slightly longer than SD2, A10 with SD2 longer than SD1, SD2 absent in A9; A1-8 with L-group bisetose, L1 longer than L2, L2 absent in A9; A1-8 with SV-group trisetose, SV3 absent in A7-9; V-group unisetose.

Pupa (Figs 10 A–C, 11 G–I), 6.37 to 8.84 mm (n = 5), elongate-oval in dorsal and ventral views, widest in the thoracic region. Integument light amber-colored, mostly smooth, with a few scattered microsetae dorsally. Frontoclypeal suture not evident. Labrum U-shaped, weakly defined. Labial palpi long; antennae arched anteriorly and separate, approximate and parallel posteriorly to distal margins of maxillae, surpassing apical margin of forewings; maxillae extending distally between sclerites of midlegs; femora of midleg not fused distally; femora of foreleg extending beyond widest part of labial palpi. Cremaster (Figs 11 G–I) short, slightly bifurcated and posteriorly directed, bearing latero-apical pair of blunt spines.

Distribution.

Palaeomystella tavaresi is known only from the type locality, in preserved fragments of the Atlantic Rain Forest at the Serra Bonita Reserve, Camacan, Bahia, Brazil.

Host plant.

Tibouchina fissinervia (Schrank & Mart. ex DC.) Cogn.( Melastomataceae ), a pioneer tree species that grows up to 20 m tall in the Atlantic Rain Forest, where it is endemic, ranging from Bahia to São Paulo ( Freitas 2011). In the Serra Bonita Reserve, these trees are relatively common at higher altitudes, above 600 m, growing spontaneously in areas that were formerly cleared for agriculture and along trails and in clearings in pristine forests, resulting from the fall of other trees.

Life history

(Figs 12 G–I). Gall prosoplasmatic histioid ( Küster, in Meyer 1987), of the rosette type (internal length from 18 to 31 mm; n = 6), induced on growing shoots causing growth of clustered short leaves (Fig. 12G); green, progressively darkening during senescence, after emergence of the moth; unilocular, unilarval. A longitudinal, narrow, cylindrical chamber is formed in the middle (Fig. 12H), where the larva develops and pupate. The mature last instar larva constructed a brown silk plug/gate near the middle of the chamber consisting of two convex hatches that open horizontally (Fig. 12I). Then it constructed a flimsy silk cocoon in the proximal sector of the chamber, where pupation occurred. To exit the cocoon the adult pushed the hatches open, and emerged through the terminal leaflets of the gall. At the type locality, the galls occur in small numbers on Tibouchina fissinervia trees, occasionally in groups of a few per plant. Under laboratory conditions, mature galls collected in the spring (October) had the adults emerging ca. 15 days later.

Etymology.

Palaeomystella tavaresi is named in memory of the Jesuit priest Joaquim da Silva Tavares, a Portuguese naturalist and a pioneer in the study and description of Brazilian cecidology ( Tavares 1917).

Remarks.

Lima (1945: 304, 305, Figs 180, 183, 184) illustrated the gall, wing venation and male genitalia of a species that he identified as a member of Walshia Clemens ( Cosmopterigidae ), reared from galls on branches of a species of Tibouchina collected in Petrópolis, Rio de Janeiro. The gall, genitalia and wing venation appear almost identical to those of Palaeomystella tavaresi and very likely represent the same species. Tavares (1917: 31, pl. 1, Figs 1, 2) described a stem gall, also from a Tibouchina sp., collected at Tijuca and Petrópolis, Rio de Janeiro, which exactly resembles the galls of Palaeomystella tavaresi . However, his description of the moths as "shiny, brunneous, with several golden spots on the upper side of forewings" does not match the one described here.

Molecular phylogeny.

A total of 660 nucleotide sites were analyzed for species of Palaeomystella from different host plants, and 211 (32%) of these were variable. According to the phylogenetic hypothesis proposed here, all species were recovered as monophyletic lineages within the Palaeomystella group of Momphidae , in both methods of inference (BI and ML) with full branch support (Fig. 13). Regarding internal relationships, Palaeomystella rosaemariae was placed as a sister of Palaeomystella tavaresi with strong posterior probability (= 1) and bootstrap (=100). Palaeomystella fernandesi was more distantly related, although with low branch support (<0.8, posterior probability; <70, bootstrap). Despite the strong internal statistical branch support of the three new lineages of momphids, the external relationships for Palaeomystella were poorly resolved (i.e., position of clades), and even the monophyly of the genus lacks statistical support. Mompha was used to root the tree, but its position as a sister clade of Palaeomystella was not supported (Fig. 13). The evolutionary divergence observed between comparisons of pairs of species was markedly high, showing greater genetic variation in this group of momphids (Table 2), particularly between clades (Fig. 13). An average of 18% ( ± 3%) of K2P differences was found between species of Palaeomystella , ranging from 14 ( ± 2%) to 24% ( ± 3%). The maximum divergence observed among clades was 20%, found between Palaeomystella fernandesi and the clade formed by Palaeomystella rosaemariae + Palaeomystella tavaresi + Palaeomystella sp. 1 (Fig. 13). The genetic divergence within Palaeomystella (ca. 18%) was greater than between this genus and Mompha (16%).