Tegmaleurodes, Martin, 2005

Martin, Jon H., 2005, Whiteflies of Belize (Hemiptera: Aleyrodidae) Part 2 - a review of the subfamily Aleyrodinae Westwood, Zootaxa 1098 (1), pp. 1-116 : 47-48

TEGMALEURODES gen. nov.

Type species Tegmaleurodes lentus sp. nov.

DIAGNOSIS—PUPARIUM. Where untreated puparia are available for study, they have no visible waxy secretions. However, during preparation for slide­mounting it becomes apparent that all puparia are protected by a tough covering, or “carapace”, that is resistant to all known chemical regimes for removal of puparial secretions: this covering often appears irregularly reticulate on slide­mounted specimens (Fig. 116), when it has not been mechanically removed. Individuals of some species develop in aggregations under leaves and are generally very cryptic, whereas puparia of some other species seen in Belize are more sparsely distributed (even if very numerous) and rusty­reddish in colour. Cuticle often entirely pale, but some species with dusky pigmentation, particularly submedially. Puparial margin clearly, but variously, modified at the tracheal openings. Longitudinal moulting suture reaching puparial margin; transverse moulting sutures usually almost reaching margin, sometimes much curved anteriad. Dorsal chaetotaxy (when discernible) typically maximally comprises paired submedian cephalic, first and eighth abdominal and caudal setae. Vasiform orifice cordate, not elevated posteriorly, mostly occupied by the operculum, but lingula often partly exposed and detail frequently visible through operculum. Segmentation often hardly evident medially, whether dorsal cover is present or absent. Geminate pore/porettes sometimes visible, sparsely distributed over dorsum.

ETYMOLOGY. The generic name derives from the latin noun tegmen (meaning a cover, covering or shield) describing the tough material secreted by the puparia.

COMMENTS. There are several whitefly species from the Neotropical Region whose puparia are protected by a tough carapace of secretion, not readily apparent when specimens are in situ on leaves but which frustrates efforts to prepare individuals for examination on slides. Amongst the better­known of such species are the members of the Trialeurodes floridensis species­group, as defined by Russell (1948) —see p. 57 and figure 128. It is instructive to quote Russell (1948:18), defining the Tr. floridensis ­group: “Dorsal layer of wax pitted and striated, tough and leathery, adhering to derm, usually present even after insects have gone through chemicals used in mounting procedure and, though transparent, tending to obscure characters.” Species regarded as belonging to Tegmaleurodes share with the Trialeurodes floridensis ­group such characters as the reduced dorsal chaetotaxy, delicate ventral (and sometimes also dorsal) cuticle, and occasional presence of leg­base spines, as well as the robust nature of the dorsal secretions. However, the shape of the vasiform orifice, almost filled by the lingula, combined with highly modified tracheal openings at the puparial margin, are characters more reminiscent of Dialeurodes sensu lato (into which group several Tegmaleurodes species had been tentatively placed, as unidentified species), but the tough dorsal covering and usually­reduced dorsal chaetotaxy preclude inclusion anywhere in the Dialeurodes ­ group, even in its broadest sense. The complete absence of submarginal glandular papillae, the relatively large puparial size, the usually­reduced dorsal chaetotaxy and the tough dorsal secretions combine to suggest that a new genus is required to accommodate such species.

Several neotropical taxa in the collection of BMNH, not belonging to Trialeurodes (see above paragraph), have the characteristic presence of a tough dermal covering (or have its former presence noted on slide labels). Many of these taxa loosely agree with the definition of Tegmaleurodes , but more detailed studies are quite likely to refine the definition, perhaps requiring further genera to be established. Resulting from this study, seven putative species from Belize have been placed in Tegmaleurodes (see Appendix 1).

Study of original descriptions of Aleuroplatus integellus Bondar (1923) and Aleuroplatus crustatus Bondar (1928) , kindly translated for the author by Antonio Aguiar, revealed conflicting descriptive information. Bondar stated that puparia of A. crustatus were observed to distort and fall from leaves as the secretions desiccated; in contrast, puparia of A. integellus were stated not to secrete visible wax although being otherwise similar to those of A. crustatus . However, there are specimens in BMNH that closely answer the description and illustration of A. integellus , and these do possess the characteristic tough secreted covering. Bondar seems rarely to have treated his specimens before immersing them in slide­mountant (personal observations), and puparia of A. integellus would almost certainly have been highly cryptic when still attached to leaves very likely leading to Bondar’s failure to observe evident secretion. The author therefore considers that Aleuroplatus integellus Bondar (1923) and Aleuroplatus crustatus Bondar (1928) should both be transferred into Tegmaleurodes , both comb. nov.