Brueelia callaeincola 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 : 490-496

Brueelia callaeincola Valim & Palma new species

( Figs 4 , 5 , 6 D, 7C,D)

Brueelia sp.; Pilgrim & Palma, 1982: 28. Brueelia sp.; Murray et al. 2006: 1958. Brueelia sp.; Palma 2010: 408.

Type host. Philesturnus rufusater (Lesson, 1828) —North Island saddleback ( Callaeidae ).

Type locality. Taranga Island (= Hen Island), North Island, New Zealand.

Other hosts. Philesturnus carunculatus (Gmelin, 1789) —South Island saddleback; Callaeas cinerea (Gmelin, 1788) —South Island kokako; Callaeas wilsoni (Bonaparte, 1851) —North Island kokako ( Callaeidae ).

Diagnosis. Brueelia callaeincola exhibits similarities with a number of species infesting thrushes ( Turdidae ): Brueelia turdinulae Ansari, 1956c , B. antiqua Ansari, 1956c , B. zeropunctata Ansari, 1957b , B. myiophoneae ( Clay, 1936) , and B. oudhensis Ansari, 1956c . These species share several characteristics with Brueelia callaeincola including the same pattern of abdominal chaetotaxy, similar male genitalia and, especially, the female subgenital plate with the posterior sclerotization of the vulvar margin not reaching the lateral sides of the vulva.

However, differences in the shape of the preantennal region, the male genitalia, and especially the shape of the dorsal anterior plate, separate B. callaeincola from the Turdidae-infesting species mentioned above.

Considering the morphological similarity of B. callaeincola with species of Brueelia from Turdidae species, we need to compare it against two similar species of Brueelia introduced to New Zealand by human agency with the introduction of the hosts Turdus merula and Turdus philomelos in the 1860’s (Checklist Committee 2010: 313), i.e. B. turdinulae and B. amsel ( Eichler, 1951) (see Palma 1999: 382). Brueelia callaeincola clearly differs from B. amsel in features of the head (size, shape of the preantennal region and of the dorsal anterior plate) and of the genitalia, which have a very different mesosomal complex and shape of parameres. Although B. callaeincola is very similar to B. turdinulae , it differs from it in details of the mesosomal complex and the shape of the preantennal region of the head.

Description. Male. Habitus as in Figs 4 A, 5A. Body with contrasting pigmentation: lateral sides of head, thorax and abdomen dark brown, medial areas much lighter.

Head: As in Figs 4 A, 5A. Preantennal region nearly rounded. Small hyaline margin distinguishable; anterior dorsal head plate not completely surrounded by the dorsal preantennal suture. Marginal carina thickened with its inner margin weakly sinuate, and completely pigmented. Lateral interruption of marginal carina incomplete, conspicuous only in dorsal view. Frontoclypeal suture with its nodal area well defined and reaching the middle of antennal fossa. Attachments of mandibular adductor muscles marked. Gular plate well pigmented and pentagonal shaped. Temples forming a rounded angle at marginal temporal setae 3 (mts3) level; temporal carina thin and slightly sinuate, reaching at most the mts3; eye only slightly embedded in marginal temporal carina. Conus reaching at most the posterior end of scapus. Setae pns and pts very reduced, with 4 sensilla (s1–s4) located between them.

Thorax: As in Figs 4 A, 5A. Pterothorax with 4–6 marginal setae on each side (spiniform and trichoid setae not included); pterothoracic apodeme well developed, reaching the lateral margin of pterothorax. Mesosternal and metasternal plates partially fused and weakly sclerotized, both slightly longer than wide, both plates bearing two long setae each.

Abdomen: As in Figs 4 A, 5a. Segments II–VIII pigmented as in Fig. 5 A. Tergal chaetotaxy: postspiracular setae long on IV–VII; one small accessory seta on V–VII (atypical specimens with only one seta in one side), and one sutural seta on II–VII. Tergite VIII with its lateral trichoid seta, plus one postero-medial and one sutural setae. Tergite IX+X not medially connected, and chaetotaxy (from lateral side to mid-line) with 1 short, 1 long, 1–2 short, 1 long, and 1 short setae. Paratergal chaetotaxy: II–III 0; IV–V 2; VI–VIII 3. Sternal plates II–VI uniformly pigmented, typically with one pair of setae on each, subgenital plate also uniformly pigmented. Porotaxy: present on tergites II–V and sternites II–VI (laterad to pair of setae). Sternal pores (= sensilla placodea) are difficult to see, except for those on sternite II ( Fig. 4 A,B), but they are present at least on one side of each segment.

Genitalia: As in Figs 4 C, 6D. Basal plate wide, with slightly concave lateral margins; parameres wide, tapering abruptly to fine-pointed tips; lateral sclerites of mesosomal complex short (1/3 of paramere length) and subconical with smooth lateral sides, bearing three sensilla on each lateral margin, one postero-dorsally (laterad to gonopore), and two antero-dorsally. The gonopore arises from an ejaculatory duct well supported by tendons of the extrusor muscle, forming a long U-shaped structure above the pore ( Fig. 4 C).

Measurements, ex Philesturnus rufusater (n = 7): HL, 0.35–0.37; POW, 0.28–0.30; TW, 0.34–0.36; ADHPW, 0.07–0.08; PW, 0.20–0.22; PTW, 0.30–0.33; AW 0.41–0.43; GL, 0.17–0.19; PrT, 0.04–0.06; and TL, 1.32–1.45.

Measurements, ex Callaeas cinerea (n = 1): HL, 0.40; POW, 0.36; TW, 0.41; ADHPW, 0.09; PW, 0.26; PTW, 0.37; AW 0.53; and TL, 1.61.

Female. Habitus as in Figs 4 B, 5B. Pigmentation of head, thorax and abdomen as in Fig. 5 B, differing from male in body size, terminalia and tergal chaetotaxy (one long postspiracular seta on IV–VII, plus one sutural seta on II–VIII). Pterothorax with 5–6 marginal setae on each side. Tergites II–VIII divided medially; tergite VIII as in male; IX–X entire and uniformly pigmented ( Fig. 7 C), with 1 long, 1 short, and 1 long setae each side ( Fig. 4 B, 7C). Paratergal chaetotaxy as for males, except one abnormal specimen with 1 seta on I–II in both sides. Subgenital plate uniformly pigmented, but distal sclerotization (= “cross piece”) does not reach the lateral sides of the vulvar margin ( Fig. 7 D), without postero-medial notch, with 3–5 (rarely 2 in one side) small setae each side ( Figs 4 B, 7D). Gonapophyses with 6–9 (rarely 3–4 on one side) short setae on each side ( Fig. 4 B). Vulva with 12–16 (very few with 3 or 5 on one side) short and spiniform setae, 4–8 long and thin setae, and 1 pair of medium-long setae situated medially and proximally to spiniform row of setae ( Fig. 4 B).

Measurements, ex Philesturnus rufusater (n = 10): HL, 0.38–0.41 (0.40±0.012); POW, 0.31–0.35 (0.33±0.011); TW, 0.36–0.40 (0.39±0.014); ADHPW, 0.07–0.09 (0.08±0.006); PW, 0.22–0.25 (0.24±0.010); PTW, 0.32–0.36 (0.34±0.012); AW 0.44–0.53 (0.48±0.027); and TL, 1.57–1.83 (1.67±0.080).

Measurements, ex Callaeas wilsoni (n = 1): HL, 0.40; POW, 0.35; TW, 0.39; ADHPW, 0.06; PW, 0.24; PTW, 0.35; AW 0.52; GL, 0.24; PrT, 0.06; and TL, 1.49.

Etymology. The species name callaeincola is formed by the prefix callae - referring to Callaeidae , the family name that the hosts belong to, and the suffix - incola (Latin) = an inhabitant.

Type material. Ex Philesturnus rufusater : Holotype ♂, Taranga Island, N.Z., Sep. 1903, A.T. Pycroft ( MONZ AI. 032894). Paratypes: 4♂, 11♀, same data as for the holotype ( MONZ AI.015796); 1♂, 3♀, same data as for the holotype ( MZUSP #5986–#5987).

Additional material examined (non-types). Ex Philesturnus rufusater : 2♀, Cuvier Island, N.Z., 15 Jan. 1977, C.R. Veitch ( MONZ AI.015797); 1♀, same data, 17 Jan. 1977, C.R. Veitch ( MONZ AI.018054); 1♂, 2♀, Tiritiri Matangi Island, AK, N.Z., 9 Sep. 1989 ( MONZ AI.015798); 2♀, Little Barrier Island, N.Z., 21 May 1990, A.J.D. Tennyson ( MONZ AI.015799).

Ex Philesturnus carunculatus : 4♂, 4♀, South Island, N.Z., 1892, Buller Collection, Canterbury Museum Skin ( MONZ AI.015800).

Ex Callaeas cinerea : 1♂, Preservation Inlet, Fiordland, N.Z., 30 Jun. 1902, Smyth Collection, Canterbury Museum Skin 1118 ( MONZ AI.015791).

Ex Callaeas wilsoni : 1♀, North Island, N.Z., no date, N.M. 17651 ( MONZ AI.015792).

Remarks. No significant qualitative differences were found among the populations of Brueelia callaeincola (totals of slide-mounted specimens: 12♂, 26♀) from the four species of regular hosts listed above. Considering that we only have a single male and a single female from Callaeas , no conclusion can be drawn from a comparison of their dimensions with those from Philesturnus lice. At present, we are confident that all the material examined belongs to the same species.

The New Zealand endemic Callaeidae is a strong monophyletic family with no clear close relatives, comprising three genera and five species ( Shepherd & Lambert 2007). One species, the huia ( Heteralocha acutirostris (Gould, 1837)) is extinct and with no Brueelia lice recorded from it ( Pilgrim & Palma 1982: 28). Considering the uniqueness of this family of birds, it is both surprising and puzzling to find that Brueelia callaeincola bears so much resemblance to species parasitic on thrushes ( Turdidae ). If these two families of birds have diverged so long ago, as the ornithological evidence indicates ( Shepherd & Lambert 2007), this is a case of either a remarkable morphological convergence among their Brueelia lice, or a relatively recent host switch of lice from a turdid to the Callaeidae or their ancestor. Although there is no evidence of any native turdid species having lived in New Zealand, the island thrush ( Turdus poliocephalus Latham, 1802 ) is widespread on islands of the tropical Pacific Ocean, including Norfolk Island in the New Zealand Subregion (Checklist Committee 2010: 313). Perhaps Turdus poliocephalus or its ancestor may have coexisted with the Callaeidae or their ancestor, thus allowing for a transfer of Brueelia from a species of Turdidae onto one of Callaeidae .

The probability that Brueelia callaeincola might be the result of a host switch from any of the two species of Turdus introduced to New Zealand by humans in the 1860’s, i.e. T. merula and T. philomelos (Checklist Committee 2010: 313) is extremely low. The widespread geographical and host distribution of B. callaeincola , the short time elapsed between the introduction of T. merula and T. philomelos and the earliest collection date of B. callaeincola (see above), and the differences, admittedly subtle, between B. callaeincola and B. turdinulae , exclude that scenario.

The absence of morphological differentiation between Brueelia populations from two apparently very different host genera— Callaeas and Philesturnus —is also surprising given the considerable genetic divergence between these two avian taxa (10% and 13% divergence for the cytochrome b and cytochrome c oxidase subunit I [COI], respectively; L.D. Shepherd pers. comm. June 2014). It seems most likely that the lack of differentiation between the Brueelia populations living on kokakos and saddlebacks results from continuous gene flow. Several species of Brueelia have been frequently recorded as dispersing by means of parasitic louse-flies which move from one host to another (phoresy) regardless of the host relationships ( Johnson et al. 2002: 245). Indeed, we have examined two females and one male Brueelia callaeincola attached to the abdomen of a louse-fly ( Diptera : Hippoboscidae : Ornithoica sp.) collected from a live North Island saddleback ( Philesturnus rufusater ) on Tiritiri Matangi Island, Hauraki Gulf, N.Z., in June 2003 by K. Hale (AI. 032857, MONZ). This is tangible evidence that this louse species does disperse by phoresy.

The lack of speciation between the Brueelia populations from Callaeas and Philesturnus is analogous to that between the Melibrueelia populations from Prosthemadera and Anthornis , as discussed above in this paper. As mentioned above under Melibrueelia novaeseelandiae , genetic studies of Brueelia callaeincola and similar species from Turdidae as well as other Brueelia from families believed to be close to the Callaeidae , may reveal the true relationships of these lice.

Figures

FIGURE 4. Brueelia callaeincola: (A) male habitus in dorso / ventral views; (B) female habitus in dorso / ventral views; (C) male genitalia.

FIGURE 5. Brueelia callaeincola: (A) male habitus in ventral view; (B) female habitus in ventral view. Scale bar = 0.5 mm

FIGURE 6. Male genitalia. Melibrueelia novaeseelandiae: (A) holotype; (B, C) two paratypes. Brueelia callaeincola: (D) holotype. Scale bars = 0.05 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.