Coraciacarus muellermotzfeldi, Dabert & Alberti, 2008

Dabert, J. & Alberti, G., 2008, A new species of the genus Coraciacarus (Gabuciniidae, Pterolichoidea) from the huia Heteralocha acutirostris (Callaeatidae, Passeriformes), an extinct bird species from New Zealand, Journal of Natural History 42 (43 - 44), pp. 2763-2776 : 2769-2775

Coraciacarus muellermotzfeldi sp. nov.

( Figures 2–4 )

Type material

Male holotype (AMU G1/1), 5 male and 3 female paratypes from Heteralocha acutirostris (Greifswald # 3677), male, New Zealand , 1879, coll. Frank. Other paratypes: 1 female from the same host species, female, same data (Greifswald # 3676). Holotype and paratypes (registration numbers AMU G1/1-8, G2/1) are deposited at A. Mickiewicz University, Poznan , Poland .

Description

Male (holotype, Figures 2 , 4A–D ). Gnathosoma with trapeziform and transversely striated subcapitulum, length to palpal tips 82, greatest width 91 (gnathosomal sizes in five paratypes 80–83 by 86–89). Setae d1 foliform, tridentate, located on apicodorsal appendix of distal podomere ( Figure 4A ). Distal podomere with two eupathidia and solenidion v clearly visible ( Figure 4B ). Idiosoma relatively stocky, slightly narrowing terminally, length 520 (490–502), width at level of setae c2 244 (233–245), length to width ratio 2.1 (2.0–2.1). Terminal part of the body with long opisthosomal lobes. Lobes triangular with medial near-square ledge and small tongue-like tips. Interlobar cleft rectangular from tips to the median ledge, in anterior part trapezoidal, total length 91 (90–95), width at level of setae h1 114 (98– 116).

Pronotal shield without ornamentation, shaped as flattened hexagon, length 128 (121–125), width at terminal margin 173 (160–169), with deep lateral incisions encompassing bases of setae se, terminal margin straight with minute median incision. Scapular setae se shaped as macrosetae, si minute, distance se–se 95 (94–99), distance si–si 52 (47–52). Vertical setae vi hair-like, at least twice as long as distance between them. Scapular shields absent; well sclerotized lateral bands in scapular region present. Hysteronotal shield covers the entire hysteronotum, anterior margin straight, length from anterior margin to bases of setae h3 370 (360–368), surface with some transverse striae in anterior two-thirds. Lateral margin of hysteronotal shield with short oblique incisions in midlength gl–e2. Terminal margin of the shield with median weakly sclerotized area reaching anteriorly the level of lateral incisions ( Figure 2B ). All dorsal and lateral hysteronotal setae short, e2, f2, h1 lanceolate, remaining ones hair-like. Setae e1 set on the level or slightly anterior to the level of gland openings gl. Setae e2 distinctly posterior to the level of ventral setae ps3. Setae f2 posterior to the level of setae h2, lanceolate. Setae h1 short, distance between their tips twice exceeds the length of the setae. Short setae ps1 set at anterior margin of bases of setae h3. Terminal setae h2 and h3 shaped as long macrosetae, h3 shorter than h2. Three pairs of dorsal cupules present: ia at the bases of setae c2, im posterolateral to d2, and ip in middle distance e2–f2. Distances between hysteronotal setae: c1–c1 73 (64–80), d1–d1 76 (63–106), e1–e1 78 (63–72), e2–e2 191 (184–195), f2–f2 185 (165–198), c1–d1 78 (68–81), d1–d2 57 (45–65), d1–e1 83 (84–92), c2–d2 117 (103–109), d2–e2 164 (168–174), e2–f2 52 (51–59), e1–f2 173 (174–188).

Epimerites I free. Ventral propodosoma without cuticular shields. Basal parts of wide lanceolate setae c3 and hairlike setae cp covered dorsally by flat semicircular lateral body extension. Ventrolateral opisthosoma with narrow, well-sclerotized opisthoventral sclerites. Genital apparatus inserted subterminally on the level of anterior ends of opisthoventral sclerites, length 35 (30–38), width 25 (20–27), without genital apodemes. Genital acetabules set far anterior to genital apparatus, posterior pair on the level or slightly anterior to the level of setae g, anterior pair distinctly anterior to setae g ( Figure 2A ). Setae g set posterior to 3a, setae 3a slightly posterior to 3b and situated approximately at level of tips of epimerites IIIa. Distances between ventral setae: 3b–3a 37 (27–32), g–3a 52 (48–52), g–4a 96 (95–101), 4a–ps3 54 (49–54). Adanal discs 22 (23–27) in diameter, corolla with several teeth, distance between centres of discs 100 (99–109).

All legs of similar length and width, without apophyses. Setae cG of genu I thick, fishbone like, two to three times longer than genu ( Figure 4D ). Solenidion S 1 on genu III inserted dorsobasally. Seta kT absent on tibia IV. Tarsus IV with six setae, seta d shaped as very short spine and shifted to middle length of the podomere ( Figure 4C ).

Female (paratype, Figures 3 , 4E,F ). Gnathosoma shaped as in male, length in four paratypes 89–91, width 95–100. Idiosoma elongated, parallel-sided, length 522–562, width 249–260, length to width ratio 2.1–2.3. Opisthosoma with short triangular opisthosomal lobes separated by shallow arched cleft; small triangular extension inserted centrally in the cleft with terminal copulatory opening. Well-sclerotized secondary sperm ducts visible far anterior near setae d1 and d2 ( Figures 3B , 4E ). Supranal concavity absent. Lateral and terminal margins of opisthosoma strongly sclerotized.

Prodorsum shaped and sclerotized as in male, length of pronotal shield 131–138, width 170–189, distances se–se 104–107, si–si 56–58, setae vi as in male. Hysteronotal shield covers almost whole hysteronotum, anterior and posterior margins straight, opisthonotal region with large U-shaped weakly sclerotized area ( Figure 3B ). Shield with transverse (anterior) and longitudinal (posterior) network-like striation. All dorsal and lateral hysteronotal setae short, e2 are longest one, wide and lanceolate (length 45–48), remaining setae hair-like. Setae e1 set posterior to the level of gland openings gl. Setae h1 set on margins of semicircular shields lying on lateral margins of U-shaped desclerotized area. Setae ps1 four times shorter than distance between them. Terminal setae h2 and h3 shaped as in male. Number and position of dorsal cupules as in male. Distances between hysteronotal setae: c1–c1 77–83, d1–d1 85–98, e1–e1 80–88, e2–e2 178–219, f2–f2 131–175, c1–d1 73–83, d1–d2 52–56, d1–e1 115– 122, c2–d2 111–119, d2–e2 193–205, e2–f2 49–55, e1–f2 153–169.

Sclerotization of ventral idiosoma as in male (with exception of lacking opisthoventral sclerites). Epigynum variable in shape and size, from large horseshoeshape with length 57 and width 77 to relatively flat and arched with length 22 and width 59; respectively tips of branches either reaching the level of setae 3b and setae 3a are inserted in middle length of branches or tips of branches not reaching bases of setae 3a ( Figure 4F ). Distances between ventral setae: 3b–3a 35–47, g–3a 46–52, g–4a 56–65, 4a– ps3 168–180. Setae ps2 set close to setae ps3, lateroterminally, distance ps2–ps2 only slightly longer than distance ps3–ps3 (46–64 versus 49–78).

Differential diagnosis

Among five species previously described the new species is more similar to species inhabiting cuculiform birds: Coraciacarus americanus de Alzuet, Cicchino and Abrahamovich, 1988 and C. cuculi ( Mégnin and Trouessart, 1884) . All these species are well characterized by combination of the following characters: pronotal shield incised laterally around setae se in both sexes, tips of lanceolate setae h1 widely separated and setae e2 situated posterior to the level of bases of setae ps 3 in males, anterior part of hysteronotal shield well developed and with big desclerotized area on opisthonotal part in females. The new species differs from these and all remaining species by long and thick setae cG on genu I in both sexes and shifting of genital acetabules slightly anterior to level of setae g in males; in other Coraciacarus species setae cG I are either thin and long or thick and short, male genital acetabules are situated posterior to genital setae. Moreover males of the new species differ also from C. americanus and C. cuculi in the following characters: (1) distance between tips of setae h1 twice exceeds the length of these setae in new species; distance between tips of h1 as long as the length of these setae in both remaining species; and (2) the main part of the hysteronotal shield is not separated from lobar parts in new species; dorsal shields of opisthosomal lobes completely separated by wide oblique gaps from the main part of hysteronotal shield in both remaining species. In addition, females of the new species differ from C. americanus and C. cuculi in the following characters: (1) setae ps2 set posterior to ps3, distance ps2–ps2 slightly longer than ps3–ps 3 in new species; setae ps2 set laterally to ps3, distance ps2–ps2 several times longer than ps3–ps 3 in both remaining species, (2) terminal margin of hysteronotal shield straight in new species; terminal margin of hysteronotal shield with median extension in both remaining species.

Etymology

This species is named in honour of Prof. Dr Gerd Müller-Motzfeld, an outstanding entomologist, former director of the institute, and head of the museum (Institute of Zoology and Museum, Ernst-Moritz-Arndt University, Greifswald, Germany).

Remarks on host–parasite relationships

Co-phylogenetic analyses of feather mites have proven that the close co-speciation with their hosts is the main evolutionary factor of their evolution in most cases ( Dabert 2005). It implies that common acarofauna of particular bird taxa originated much more probably as a result of co-phylogenesis rather than colonization.

Coraciacarus inhabits birds from four orders: Cuculiformes , Coraciiformes , Musophagiformes and Passeriformes . Being aware that drawing conclusions from parasite phylogeny about the phylogenetic relationships between their hosts is a prohibited procedure in phylogeny reconstruction we can suggest only that a common Coraciacarus acarofauna of these four bird orders might point to close relationships between some of them. The close phyletic relationships between Musophagiformes and Cuculiformes , and to a lesser degree also to Coraciiformes , are generally accepted ( Livezey and Zusi 2007; but see also Sibley and Ahlquist 1990). The fourth host group, Callaeatidae , is undoubtedly a corvid member of the Passeriformes ( Barker et al. 2004; Shepherd and Lambert 2007), birds sometimes treated as relatively close to Coraciiformes ( Livezey and Zusi 2007) and sometimes as very distant to the three remaining host orders of Coraciacarus ( Sibley and Ahlquist 1990) . Therefore it is very risky to conclude that the presence of Coraciacarus on huia is a result of a common ancestry of this bird with the remaining three bird orders and is a relic of an ancient co-speciation between the slowly evolving mite and its hosts. A more realistic explanation of the presence of Coraciacarus on Heteralocha acustris is horizontal transfer. The only possible ‘‘donors’’ are cuckoos ( Cuculiformes ) because bee-eaters ( Coraciiformes , Meropidae ) and turacos and plantain-eaters ( Musophagiformes ) are not represented in the avifauna of New Zealand. However, ambiguities still exists because the only two recent species of New Zealand cuckoos ( Chrysococcyx lucidus and Eudynamys taitensis ) are typical brood parasites and no data about possibly extinct cuckoos are available. The transfer from foster parents to young cuckoo was frequently observed ( Dubinin 1951) while the reverse direction of mite transfer is practically impossible. The presence of nonparasitic cuckoo(s) in the former avifauna of New Zealand is not confirmed. The reasons for the presence of Coraciacarus on huia therefore remain unresolved at this stage of our knowledge about the acarofauna of Callaeatidae and other recent and extinct New Zealand birds.

Key to species of the genus Coraciacarus Dubinin, 1956

1. In both sexes pronotal shield incised laterally around setae se........ 4.

In both sexes pronotal shield not incised laterally................ 2.

2. In both sexes setae si set much closer to respective setae se than to midline of the shield. In males setae e2 thin, needle-like. In females rounded and closed supranal concavity well developed on dorsoterminal end of hysteronotum; setae e2 short, at most as long as half of the distance e2–h1 .............................. C. musophagi ( Trouessart, 1886)

In both sexes setae si inserted equidistantly to respective setae se and midline of the shield. In males setae e2 wide, lanceolate. In females closed supranal concavity absent; setae e2 as long or longer than distance e2–h1 ( C. meropsi Dubinin, 1956 )........................................ 3.

3. In males medial incision of terminal margin of hysteronotal shield very short, several times shorter than distance e1–e1. In females length to width ratio of idiosoma is 2.3–2.6; terminal lobes and interlobar cleft as flat triangles, the length much smaller than the width of their bases................................. C. m. meropsi Dubinin, 1956

In males medial incision of terminal margin of hysteronotal shield at least as long as distance e1–e1. In females length to width ratio of idiosoma is 3.0– 3.3; terminal lobes and interlobar cleft as sharp triangles, as long as the width of their bases..................... C. m. leptus Gaud, 1978

4. In males tips of lanceolate setae h1 widely separated, e2 situated posterior to the level of setae ps3 bases. In females anterior part of hysteronotal shield well developed and with big desclerotized area on opisthonotal part... 5.

In males tips of needle-like setae h1 touching each other; setae e2 shifted anterior to the level of setae ps3 bases. In females anterior part of hysteronotal shield completely reduced from the level of trochanters III and well sclerotized in opisthonotal part.......... C. dithyridus Gaud, 1966

5. In both sexes setae cG on genu I thick, fishbone-like. In males the main part of hysteronotal shield not separated from lobar parts; posterior pair of genital acetabula set on the level or anterior to the level of genital setae g. In females setae ps2 set posterior to ps3, distance ps2–ps2 slightly longer than ps3– ps3; terminal margin of hysteronotal shield straight...................................................... C. muellermotzfeldi sp.n.

In both sexes setae cG on genu I thin, hair-like. In males the main part of the hysteronotal shield completely separated by oblique gap from lobar parts; both pairs of genital acetabula set posterior to the level of genital setae g. In females setae ps2 set laterally to ps3, distance ps2–ps2 several times longer than ps3–ps3; terminal margin of hysteronotal shield with median extension..................................... 6.

6. In males entire hysteronotal shield uniformly dotted. In females epigynum arched, at most reaching by branch tips the bases of setae 3a ........................ C. cuculi ( Mégnin and Trouessart, 1884)

In males anterior half of hysteronotal shield with transverse striae. In females epigynum semicircular, branches long with bases of setae 3a inserted in the middle of their length.................................

......... C. americanus de Alzuet, Cicchino and Abrahamovich, 1988

Figures

Figure 2. Coraciacarus muellermotzfeldi sp. nov., male. (A) Ventral view, (B) dorsal view. Setal designations of idiosoma after Griffiths et al. (1990).

Figure 3. Coraciacarus muellermotzfeldi sp. nov., female. (A) Ventral view, (B) dorsal view.

Figure 4. Coraciacarus muellermotzfeldi sp. nov., details. (A) Palpus, dorsal view, (B) palpus, ventral view, (C) tibia and tarsus of leg IV in males, (D) genu of leg I, (E) secondary sperm ducts in females, (F) morphological variability of epigynum shape in females. Setal designations of legs and palps after Gaud and Atyeo (1996).