Wallacella, Mielke & Grehan & Cock, 2020

Mielke, Carlos G. C., Grehan, John R. & Cock, Matthew J. W., 2020, Ghost-moths of Trinidad and Tobago with description of a new genus and a new species (Lepidoptera: Hepialidae), Zootaxa 4758 (1), pp. 181-190 : 182-184

Wallacella , gen. nov.

( Figs 1a, 1b, 2, 3, 4, 5, 6 , 10, 11, 12, 13a, 13b, 13c, 14, 15 )

Type species: Phassus guianensis Schaus, 1940 , by present designation and monotypy.

Diagnosis. Recognized by the distinctive and unique shape of the posterior male abdomen (asymmetrical tergite VIII) and genitalia (tergal lobes asymmetrical and pocket-like ventral projection of the saccus). In addition by the following combination of characters: i) male labial palpus two-segmented, ii) antennal rami long and flattened, ii) ‘hepialine’ venation ( Dumbleton 1966), and iv) the pseudotegumen dorso-mesally unfused while ventro-mesally fused.

Description. Male ( Figs 1a, 1b, 2, 3, 4, 6 , 10, 11, 12, 14 ). Head. Clypeus glabrous anteriorly and mesally projected, and differentiated from the frons. Frons with long scales at the distal edge of the scape, piliform, and porrect. Vertex scales as the frons. Eyes large, occupying 4/5 of the head in anterior view. Labial palpus stout with two palpomeres; distal palpomere embedded dorsally to the basal palpomere; length of palpomeres as long as the subtriangular prelabium. Antenna bipectinate, dark brown; dorsal rami shorter than ventral rami; rami flattened; sensilla caetica present, sensilla trichodea absent.

Thorax. Legs ( Fig. 10 ). Male legs lacking specialized androconia; metaleg reduced; arolium absent. Fore- and hindwings ( Fig. 6 ). Hepialine venation as in Cibyra Walker ( Mielke & Casagrande 2013); Sc1 present on the forewing and hindwing with CuP complete and a single A vein present.

Abdomen ( Figs 11, 12, 14 ). Tergite VIII bilobed, asymmetrical, with right lobe greatly projected posteriorly; sternite VIII in two portions with a main central sclerite and two detached postero-lateral plates.

Male genitalia ( Figs 13a, 13b, 13c, 15 ). Tegumen (= intermediate plate) as a narrow bar, fused to the pseudotegumen, but distinguished by sclerotization and ventrally articulated with saccus. Saccus U-shaped with a conspicuous and ventral projection forming a pocket with its posterior edge heavily sclerotized. Tergal lobes asymmetrical as an extension of dorsal processes of the pseudotegumen. Pseudotegumen dorso-mesally unfused and ventro-mesally fused. Fultura inferior (= juxta) and fultura superior (= trulleum) both form well sclerotized plates. Valva digitiform. Phallus membranous.

Female ( Fig. 5 ). Examined only as a photograph. Hindwing includes 2A.

Etymology. Wallacella , gen. nov., is named after Alfred R. Wallace for his important contributions on the Lepidoptera in the 19 th century. The name follows the tradition of Druceiella (Viette) , Dugdaleiella (Grehan & C. Mielke) , Hampsoniella (Viette) , Huebneriella (C. Mielke & Grehan), Kozloviella (Grehan & C. Mielke), Pfitzneriella (Viette) , and Walkeriella (C. Mielke, Grehan & Grados) . The gender of the name is feminine.

Geographical distribution. Wallacella , gen. nov., is known to occur in the Northern South America from Venezuela to Northern (Pará) and Northeastern (Maranhão) Brazil ( Fig. 20 ).

Remarks. The presence of a posterior lateral knob (not strongly developed) on the tergosternal connection, a broad intermediate connection between the tergosternal bar and the lateral ridge, and a broken anterior margin at the tergosternal connection, along with a very close parallel position between the hindwing Sc and Rs veins, support inclusion of Wallacella , gen. nov., within the ‘cibyrine’ cluster of genera ( Grehan 2012). Phylogenetic affinity within the cibyrine cluster is currently unresolved due to the lack of identified apomorphies shared between genera. The female genitalia are not known for many taxa and male genitalia often show distinct features shared by only one or a few species and this has contributed to the designation of several monotypic genera. A revision of Druceiella (Viette) by Grehan & Rawlins (2018) noted that this genus shared a pattern of three darker forewing patches with Pfitzneriana (Viette) and Wallacella [as ‘ Phassus ’] guianensis , comb. n., although this is less distinct in the latter species. The three genera also shared an apically fused apex of the pseudotegumen that is also strongly sclerotized and lined with transverse grooves and a sclerotized expansion of the posterior saccus in the form of a central rectangular protuberance in Pfitzneriana and an enlarged rim with laterally projecting tubercles in Wallacella , gen. nov. Druceiella and Wallacella , gen. nov., have an asymmetrical posterior abdomen margin with a posteriorly projecting lobe which is on the left in Wallacella , gen. nov., and on the right in Druceiella . Since this projection represents a uniquely derived feature within the Hepialidae it is tempting to see it as a potential synapomorphy for these two genera since they both occur in Northern South America and the feature has not been recorded in any other Hepialidae . An additional feature indicative of potential close relationship is the shape and size of the sclerotized tergal lobes which are asymmetrically expanded on the right side in Druceiella and on the left side in Wallacella , gen. nov., but the presence of this feature also needs to be further assessed in other genera. The male antennae of Druceiella and Wallacella , gen. nov. share similarly long and flattened rami.

The Brazilian specimens examined of Wallacella , gen. nov., have not been assigned to W. guianensis pending future investigation of their species status.

Figures

FIGURE 20. Geographical distribution of Wallacella guianensis, comb. nov., and Gymelloxes juliusboosi, sp. nov., in Northern South America. Trinidad and Tobago inset.

FIGURES 1−6. Wallacella guianensis, comb. nov. 1−4, Male: 1a, dorsal view; 1b, ventral view (Trinidad, Off Saunders Rd, Inniss Field; CGCM 35.217; MJWC); 2, dorsal view (Trinidad, Off Saunders Rd, Inniss Field; CGCM 35.356; MJWC; lines: i—proximal antemedial, ii—distal antemedial, iii—proximal postmedial, iv—premarginal); 3, dorsal view (French Guiana; CGCM 33.107); 4, dorsal view, holotype of Phassus guianensis (USNM). 5, Female: dorsal view (MHNH). 6, Male wing venation (CGCM 30.158). Scale bar = 1 cm.

FIGURES 10−15. Wallacella guianensis, comb. nov. 10, Legs (CGCM 30.158). 11−12, Male abdomen (CGCM 35.217): 11, upper dorsal, lower ventral view; 12, tergum and sternum VII and VIII. 13, Male genitalia (CGCM 35.217): 13a, lateral view; 13b, anterior view; 13c, ventral view (pseudotegumen upwards). 14, Male abdomen (holotype), tergite and sternite VII and VIII. 15, Male genitalia (holotype), ventral view (unscaled). Scale bar = 1 mm.