Trialeurodes abdita, 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 : 54-55

Trialeurodes abdita sp. nov.

(Figs 61, 125)

PUPARIUM. Habitus. Appearance of empty pupal cases silvery and difficult to see because of sparse secretions; under a handlens a fine secreted filament can be seen to issue from each submarginal papilla, to form a translucent peripheral fringe (Fig. 125); dorsum without evident secretion. Margin. Outline elongate­oval, 0.81–1.07 mm long, 0.38–0.48 mm wide, about 2.00–2.50 times longer than wide, generally widest opposite transverse moulting sutures (n=15). Margin with shallow and very irregular­sized crenulations, 12–15 per 0.1mm of lateral margin, sometimes very slightly modified at thoracic and/or caudal tracheal openings. Dorsum. Longitudinal moulting suture reaches puparial margin; transverse moulting sutures terminate in submargin in pupal cases vacated by adults. Dorsal disc with abdominal segmentation rather indistinct and only marked into subdorsum, with cephalothoracic divisions even less marked. Abdominal segment VII about half length of segment VI medially. Submedian abdominal depressions not evident. Submargin with row of pronounced papillae, all acute and most longer than wide, each less than one papilla­width from its adjacent neighbour, occasionally a very small number occurring mesal to main row (Fig. 61); papillae uneven in size, largest twice length of smallest and similar in length to lingula head; laterally several small papillae alternate with each large papilla, but most papillae larger at anterior and posterior ends of pupal case; holotype bearing 96 papillae (48 on cephalothorax and 48 on abdomen) on one side of pupal case. Cuticle of dorsal disc generally smooth but often densely punctuated by granular “mottling” which is more evident in “quickmounted” pupal cases not treated chemically (Fig. 125). Vasiform orifice elongate­cordate, longer than wide, less sharply defined at its posterior apex which is slightly notched, with a small tubercle at anterior end of this notch; vasiform orifice fluted internally, inset from posterior puparial margin by a little over its own length; operculum laterally­rounded trapezoidal, occupying basal half of vasiform orifice, without evident posterior marginal setae; lingula head completely exposed beyond operculum but included in vasiform orifice, with 3 pairs of lateral lobes and pair of apical setae. Caudal furrow hardly evident. Chaetotaxy. Anterior marginal setae not seen in small study sample; posterior marginals fine, hair­like, about half length of caudal setae. Single pairs of cephalic, first and eighth abdominal and caudal setae present, all longer than posterior marginals but similar in size to each other, similar to length of vasiform orifice (Fig. 61); first abdominal setae situated near segment I/II division, eighth abdominal setae situated lateral to anterior edge of operculum, caudal setae situated between posteriormost pair of papillae. Pores. Immediately mesal to row of submarginal papillae is a row of unevenly­spaced tiny dark pores, fewer in number than papillae (Fig. 61, expanded detail). Small dorsal disc pores present, apparently not geminate, irregularly positioned with usually 1–2 on each side of abdominal submedian area and a few more distributed across subdorsum and submargin, and similarly distributed on cephalothorax. Venter. Ventral abdominal setae long and fine, similar to posterior marginal setae, rather close to median line and underlying vasiform orifice and operculum. Legs normal, each with an apical pad and a stout basal spine, sometimes a second (smaller) spine and a tiny seta also present basally (but see comments, below). Antennal bases situated slightly anterior to fore legs, antennae similar in length to fore legs and often overlapping them. Tracheal folds not marked. Ventral cuticle extremely fragile—see comments, below.

MATERIAL EXAMINED. Holotype post­emergence pupal case, BELIZE, CFR, San Pastor trackside, on Lasiacis sp. (Poaceae) , 29 v.2004 (J.H.Martin #7937) ( BMNH). Paratypes: 19 post­emergence pupal cases or damaged puparia, same data as holotype ( BMNH).

ETYMOLOGY. The specific epithet is the latin adjective abdita (meaning concealed or secret), reflecting the discovery of specimens only on grass leaves deep in a thicket, close to the ground.

COMMENTS. The puparia of T. abdita secrete no evident waxy material on the dorsal surface, but on two chemically­untreated individuals the fine peripheral wax filaments are clearly visible (Fig. 125), one filament issuing from each submarginal papilla. This species is represented by only one small sample, mainly comprising post­emergence pupal cases. Despite very careful removal from the blades of their host grass, most of their ventral surfaces are damaged and incomplete, with the middle pair of legs being the feature lost most often. The specimen selected as holotype has one side of the dorsal cephalothorax missing, but the chaetotaxy is otherwise complete, and all legs are present on one side, allowing most features to be observed satisfactorily. On the same slide, one paratype specimen has legs that are more complete than in the holotype, but has suffered substantial loss of setae.

This species does not appear to belong to any of the species groupings defined for the North American Trialeurodes species by Russell (1948). T. abdita is perhaps closest to the T. vaporariorum group, with fragile pale cuticle, wax secretions only evident peripherally and abdominal segment VII well defined medially: however, the presence of stout spines at the bases of the puparial legs precludes inclusion in this group, as do the particularly acute submarginal papillae. The combination of acute papillae and stout leg­base spines is reminiscent of the Old World T. ricini (Misra) ­group, but puparia of members of the T. ricini ­group secrete a tough, gelatinous dorsal carapace that resists chemical de­waxing.

T. abdita shares its host plant in Belize with Aleurocybotus cereus and Aleurotulus laneus , both described above, but its puparial secretions are very fine and almost invisible, in contrast to the flocculent secretions of the other two species.