Phyllonorycter grewiaecola (Vari, 1961)

Prins, Jurate De & Kawahara, Akito Y., 2012, Systematics, revisionary taxonomy, and biodiversity of Afrotropical Lithocolletinae (Lepidoptera: Gracillariidae), Zootaxa 3594 (1), pp. 1-283 : 76-77

The grewiaecola group

The grewiaecola group includes two species: Phyllonorycter grewiaecola ( Vári, 1961) and P. grewiaephilos De Prins , n. sp. Adults belonging to the grewiaecola group can be distinguished by a characteristic forewing pattern: two very oblique slender white fasciae, blackish margined from both sides, second fascia sinuating from costa, elongate towards apex, the third group of white markings at subapical sector consisting of a triangular dorsal strigula and a elongate apical stripe ( Vári 1961: pl. 22, fig. 7). White markings edged on both sides. Forewing more or less lanceolate, the costal margin is not convex but straight with slight declination at apical part. The joining vein between R 4 and R 3 in the grewiaecola group is rudimentary, very slender and indistinct. There are no differences in external features between those two species assigned to the grewiaecola group. Therefore, only dissections of genitalia provide the means for an accurate identification. Larvae construct underside tentiform mines on Grewia spp. (Malvaceae) . Pupa possesses a rudimentary cremaster ( Figs 136–141 ), pupation without cocoon ( Vári 1961).

The male genitalia of the grewiaecola group are characterized by a trilobed tegumen, which is a unique character among all Lithocolletinae and is a putative apomorphy for this group. Valvae symmetrical, long, narrow, curved, haired and/or covered with tubercles, rounded at apex. Transtilla not complete. Vinculum narrow Ushaped; saccus median or long. Anellus developed, it might carry fultura superior. Aedoeagus short, thick, slightly sinuating, coecum enlarged, vesica with long, narrow cornuti. Sternum VIII in males flap-like, extended, densely covered with tiny nodules, deeply or shallow bifurcate caudally.

Female genitalia segment VIII short, well connected with segment VII. Posterior apophyses with enlarged basal 1/3 and with enlarged bases; anterior apophyses initiate at middle of segment VIII from rather broad sclerotized plate. Ostium bursae opens in subposterior sector of segment VII. Sterigmatic sclerotizations located at subposterior sector of segment VII, well developed with long narrow lateral appendages of lamella antevaginalis, act as a third pair of apophyses. Anterior margin of segment VII ca. 2× broader than posterior margin. Ductus bursae wide, corpus bursae elongate sac-shaped, with one moderate signum with fine median ridge.

Note: this group of species shares a lot of morphological characters with Cameraria : i) presence of sinuate fasciae; ii) presence of lateral appendages on tegumen; iii) narrow rod-like valva covered with tubercules, iv) bifurcate sternumVIII in males, v) signum area on copus bursae crossed by median ridge in females. However, the pupal morphology corresponds to Phyllonorycter : i) pupal abdominal segments are covered with dense minute spines, whereas in C. ohridella the pupal abdominal segments carry an inwardly curved thorn and/or a spine ( De Prins et al. 2003); ii) cremaster present, though it is rudimentary. The grewiaecola group probably occupies an intermediate position between Cameraria and Phyllonorycter and therefore it is difficult to place it. Probably this species group is an ancestor and might be somewhere at the base position of splitting of the highly divergent Cameraria and Phyllonorycter . The generic affinities in morphologically resembling oriental species like C. bauhiniae , C. quadrifascia , C. barlowi , C. trizosterata , C. fasciata are rather vague as well ( Kumata 1993). Therefore, it seems preferable at the moment to follow a more conservative approach leaving this group in Phyllonorycter , as initially proposed by Vári (1961: 212) and mainly considering the pupal and genital morphology until additional morphological and molecular data are obtained.

Key to the species of the grewiaecola group based on male genitalia

1. Anellus with well sclerotized fultura superior bearing two sinuate, slender horns; saccus ca. 1/3 length of valva, gradually accuminate caudally; sternum VIII deeply emarginated caudally ( Figs 191, 192, 194, 196, 197 )............ 21. grewiaecola

– Fultura superior on anellus not developed; saccus slightly longer than 1/2 of valva length, equally slender along entire length; sternum VIII, with shallow semi-round emargination ( Figs 198, 199 )................................22. grewiaephilos

Key to the species of the g rewiaecola group based on female genitalia

1. Sterigma well developed and heavily sclerotized cup-shaped with broad lamella antevaginalis; anterior apophyses ca. 1/2 as long as posterior apophyses; signum on corpus bursae oval-shaped with sclerotized median ridge ( Fig. 312 ).. 21. grewiaecola

– Sterigma mountain-shaped with narrow lamella antevaginalis; anterior apophyses ca. 3/4 as long as posterior apophyses; signum on corpus bursae diamond-shaped, with sclerotized median ridge ( Fig. 313 )......................22. grewiaephilos

Figures

FIGURES 136–141. Exuvium of Phyllonorycter grewiaephilos. 136, ventral view. 137, lateral view. 138, terminal segment, caudal view. 139, terminal segment, ventral view. 140, terminal segment, lateral view. 141, small cremaster on terminal segment.

FIGURES 191–197. Male genitalia. Scale bar 100 µm. 191–197, Phyllonorycter grewiaecola. 191–193, genitalia prep. MRAC/KMMA 00273, in RMCA. 191, ventral view. 192, sternum VIII. 193, aedoeagus. 194–197, genitalia prep. TMSA 14603, in TMSA. 194, valva. 195, aedoeagus. 196, sternum VIII. 197, fultura superior.

FIGURES 198–200. Male genitalia. Scale bar 100 µm. 198–200, Phyllonorycter grewiaephilos, paratype, genitalia prep. MRAC/KMMA 00264, in RMCA. 198, ventral view. 199, sternum VIII. 200, aedoeagus.

FIGURES 312–313. Female genitalia. Scale bar 200 µm. 312, Phyllonorycter grewiaecola, genitalia prep. MRAC/KMMA / 00277, in RMCA. 313, Phyllonorycter grewiaephilos, paratype, genitalia prep. MRAC/KMMA 00265, in RMCA.