Melibrueelia Valim & Palma

Valim, Michel P. & Palma, Ricardo L., 2015, A new genus and two new species of feather lice (Phthiraptera: Ischnocera: Philopteridae) from New Zealand endemic passerines (Aves: Passeriformes), Zootaxa 3926 (4), pp. 480-498 : 483-484

Melibrueelia Valim & Palma new genus

Type species: Melibrueelia novaeseelandiae new species.

Diagnosis. The new genus is morphologically close to some species of Brueelia from Timaliidae , Corvonirmus from Corvidae , and Turdinirmus from Turdidae (see Table 1). However, both sexes of Melibrueelia can be distinguished from them by this combination of characters: (1) a well formed anterior dorsal head plate, (2) a lateral split of the marginal carina, (3) a seta accessory to the post-spiracular seta on segments III–VII, (4) tergopleurites II without anterior setae, (5) male head shape, (6) male antennae with scapus and last two distal flagellomeres enlarged, (7) female tergite XI fused with IX+X, and (8) reticulation in the subgenital plate.

Males of Melibrueelia have the distal antennal flagellomeres swollen and dorsally unsclerotized, but still showing a line of division, appearing as a "pseudo-fusion". Males of some species of Corvonirmus and Paragoniocotes have an enlarged scapus, but the flagellomeres are uniformly sclerotized and not enlarged. As in Melibrueelia, some species of Brueelia parasitizing the passerine families Timaliidae (e.g. B. antennatus Ansari, 1956b , B. mahrastran Ansari, 1956b , B. longisternus Ansari, 1956b ) and Estrildidae (e.g. B. stenozona Kellogg & Chapman, 1902 ) also have sexually dimorphic antennae with an enlarged scapus in males ( Ansari 1956b, 1957a), but males of Melibrueelia also have swollen distal antennal flagellomeres, and a tuft of less than 10 pleural distal setae on each side of segments IX+X. Furthermore, both sexes in species of Corvonirmus have a sub-spherical head shape with a convex preantennal margin, and accessory setae to the post-spiracular seta on tergites II–VII ( Ansari 1956a, 1957a). The male genitalia of Melibrueelia are similar to those found in some species of Brueelia from Timaliidae (e.g. Ansari 1956b: figs 24–26).

Regarding females, species of Corvonirmus and those of the Brueelia “ longisternus subgroup” from Timaliidae have tergites IX+X not fused with XI, unlike Melibrueelia which has tergites IX+X+XI fused (see Table 1). However, females of Turdinirmus do have tergites IX+X fused with XI, but can be separated from those of Melibrueelia either by their subgenital plate being nearly square distally (i.e. not forming a “cross piece”) or by the presence of post-spiracular setae on segments IV–VII (see Table 1).

Females of some Brueelia sensu lato (e.g. B. grandalae ( Clay, 1936) , B. antennatus Ansari, 1956b , B. effronte Ansari, 1956b , B. impressifrons Ansari, 1956b , B. novofacies Ansari, 1956b ) have a fused terminal tergite (IX+X+XI), but those species differ from Melibrueelia either by the shape of preantennal region or by not having sexually dimorphic antennae.

Females of some species of Meropsiella (e.g. Meropsiella erythropteri ( Piaget, 1885) new combination and M. bullockoda ( Williams, 1981) new combination) also have tergite XI fused with IX+X, but both sexes of Meropsiella are distinct from those of Melibrueelia in head features and by having 4 setae on sternites VI (usually only 2 setae on most genera of the Brueelia -complex) and no post-spiracular setae on segment III.

Females of species of Formicaricola and Formicaphagus have tergite XI fused with IX+X, but they differ from those of Melibrueelia by not having: (1) reticulation in the subgenital plate, (2) tergopleural setae and accessory seta to the post-spiracular seta on III, and (3) a distal “cross piece” in the subgenital plate. Males of Formicaricola and Formicaphagus lack: (1) both tergopleural setae and accessory seta to the post-spiracular seta on III, and (2) antennal swellings.

Description. Both sexes. Head: symmetric, with triangular preantennal region ( Figs 1 A,B–2); dorsal preantennal region with well-formed dorsal anterior plate well delineated; marginal carina interrupted in the midline with its extremes joined by a hyaline margin, but dsms (dorsal submarginal seta) arises from an unsclerotized area which divides the marginal carina forming a discrete lateral division, and the dorsal preantennal suture arises from this discrete division laterally from the marginal carina ( Fig. 2 ). Ventral carina interrupted medially and fused anteriorly on each side with marginal carina; each half of the divided carina entirely sclerotized and with a flattened portion to which the lobe of the pulvinus is attached ( Fig. 2 B). Pulvinus with definite lateral lobes attached to flattened parts of the ventral carinae. Ocular and preocular setae short, preocular seta set submarginally and posterior to eye lens. Anterior ventral setae (avs): two long (avs2-3), one medium (avs1). Postantennal region without sutures or developed temporal carina; both post-nodal seta (pns) and post-temporal seta (pts) very reduced. Head sensilla present (s1–s4), each bearing a very reduced seta. Marginal temporal seta 3 (mts3) very long, all others (mts1–2, mts4–5) very short ( Figs 2 A,B). Occipital carina present, weakly sclerotized. Gular plate roughly pentagonal in shape and well sclerotized ( Fig. 3 ).

Thorax: As in Fig. 1 A,B. Prothorax roughly rectangular, with one pair of medium-long post-spiracular setae; pterothorax without signs of division between meso- and metathorax, and with one spine-like, one trichoid, and ca. 6 setae each side of its posterior margin. Legs without distinctive features.

Abdomen: Distinctly sexually dimorphic ( Figs 1 A,B, 3), but with similar chaetotaxy pattern in both sexes; pleural setae present on IV–VIII; accessory to post-spiracular seta present on III–VII; post-spiracular setae present on V–VII. Porotaxy: sensilla present on tergites II–V and sternites II–VI (laterad to pair of setae).

Male. First antennal segment (scapus) very enlarged, and last three flagellomeres swollen ( Figs 1 A, 2A). Ventral surface of distal three flagellomeres normally sclerotized and clearly divided, but dorsally unsclerotized from distal end of flagellomere I to flagellomere IV, and faintly divided. Abdomen ovoid ( Figs 1 A, 3A). Tergopleural plates roughly triangular. Anal and genital openings (and anal setae) close together on the dorsal surface. Tergal plates IX+X fused, distinct and medially divided. Tergite XI as a thin transverse band sclerotized on each side but not in the middle line ( Fig. 1 A). Genitalia as in Figs 1 C, 6A–C.

Female. Abdomen elongated ( Figs 1 B, 3B) and antennae filiform ( Fig. 2 B). Subgenital plate reticulated medially ( Figs 1 B, 3B, 7B), with sclerotization on distal vulvar margin ("cross piece" of Ansari 1956b). Tergites IX–X–XI fused in a single plate ( Fig. 7 A).

Etymology. The name Melibrueelia is formed with the prefix Meli - (Greek) = honey, referring to the host family Meliphagidae , and the suffix - brueelia referring to the widespread and closely related genus Brueelia . Gender: feminine.

Remark. Considering that the new genus is at present monotypic, it is difficult to ascertain the boundaries of its range of morphological variation. It is expected that some the features described above for the genus may prove to be useful for species-level differentiation only.

Figures

FIGURE 1. Melibrueelia novaeseelandiae: (A) male habitus in dorso / vental views; (B) female habitus in dorso / vental views; (C) male genitalia. Abbreviation: ter XI = Tergite XI.

FIGURE 2. Melibrueelia novaeseelandiae: (A) male head in dorsal view; (B) female head in dorso / vental views. Abbreviations: as, anterior seta; ads, anterior dorsal seta; avs, anterior ventral seta; co, conus; dap, dorsal anterior plate; dprs, dorsal preantennal suture; dsms, dorsal submarginal seta; el, eye lens; hm, hyaline margin; mc, marginal carina; mds, mandibular seta; mtc, marginal temporal carina; mts, marginal temporal seta; os, ocular seta; pas, preantennal seta; pcs, preconal seta; pns, postnodal seta; pos, preocular seta; pts, postemporal seta; s, sensilla; vap, ventral anterior plate; vsms, ventral submarginal seta.

FIGURE 3. Melibrueelia novaeseelandiae: (A) male habitus in ventral view; (B) female habitus in ventral view. Scale bar = 0.5 mm

FIGURE 7. Female terminalia. Melibrueelia novaeseelandiae: (A) dorsal view; (B) ventral view. Brueelia callaeincola: (C) dorsal view; (D) ventral view. Abbreviations: pssVII, postspiracular seta of tergite VII; tr, trichoid seta of the tergite VIII.