Myrsidea hihi Sychra, Kolencik & Palma, new species

Myrsidea hihi Sychra, Kolencik & Palma new species

Figs 12–13, 22, 29–30.

Myrsidea sp.; Pilgrim & Palma 1982: 27. Myrsidea sp.; Murray et al. 2001: 1263. Myrsidea sp.; Palma 2010: 408.

Type host:. Notiomystis cincta (du Bus de Gisignies, 1839) —stitchbird or hihi (Notiomystidae)

Type locality. Mount Bruce, Wairarapa, New Zealand.

Diagnosis. Myrsidea hihi is morphologically close to Myrsidea novaeseelandiae (see above). See Table 1. to distinguish the females of these two species.

Description. Female (n = 11). As in Figs 12 and 29. Hypopharyngeal sclerites weakly developed. Length of dorsal head seta (DHS) 10, 0.105–0.130; DHS 11, 0.090–0.100; ratio DHS 10/11, 1.10–1.33. Labial setae 5 (ls5) 0.07–0.09 long, latero-ventral fringe with 7–10 setae. Gula with 4–5 setae on each side. Pronotum with 6 setae on posterior margin and 3 short spiniform setae at each lateral corner. Prosternal plate as in Fig. 13. First tibia with 3 outer ventro-lateral and 3 dorso-lateral setae. Metanotum enlarged, with 6–8 marginal setae (Fig. 12); metasternal plate with 7–8 setae, and a long, pigmented distal prolongation (Fig. 29); metapleurites with 3–4 short strong spiniform setae and 1–2 long seta. Femur III with 1 1–15 setae in ventral setal brush. Tergite I larger than remainder; tergites II–V not enlarged, sinuous (Fig. 12). Abdominal segments with continuous row of tergal setae at least across segment II–V. Tergal setae: I, 4–5; II, 13–17; III, 14–17; IV, 12–16; V, 10–13; VI, 8–10; VII, 5–7; VIII, 4. Longest tergocentral seta on segment II is quite long (0.25–0.33). Postspiracular setae: extremely short on I, long on II, IV and VIII (0.33–0.44), shorter on VII (0.16–0.21), and shortest on III, V and VI (0.08–0.19). Inner posterior seta of last tergite 0.04–0.05 long, not longer than anal fringe; short lateral marginal seta 0.02–0.03 long. Pleural setae: I, 2; II, 8–12; III, 8–14; IV, 9–13; V, 8–12; VI, 6–10; VII, 3–7; VIII, 3. Pleurite I with only short spine-like setae; pleurites II–IV with 6–11 slender and longer setae; pleurites III–VII with 1–3 anterior setae. Pleurite VIII with inner setae (0.03–0.05) as long as outer (0.03–0.04). Sternal plate II divided in three sections by two unpigmented oblique “sutures” (Fig. 29). Sternal setae: I, 1–3 setae on each latero-posterior angle; II, 4–6 in each aster—aster setae length: s1, 0.11–0.13; s2, 0.05–0.10; s3, 0.04–0.07; s4, 0.04–0.05; s5, 0.04–0.05; s6, 0.05— with 19–24 marginal setae between asters, and 8–17 medioanterior; III, 50–73 marginal setae (3–12 medioanterior setae); IV, 64–79 (9–15); V, 65–80 (10–15); VI, 58–74 (8–17); VII, 40–54 (9–14); VIII–IX, 27–40, and 15–16 setae on lightly spiculose vulvar margin. The outer latero-marginal setae on sternite III very long, reaching well beyond the posterior margin of sternite IV (Fig. 12). Subvulval sclerite (sternite IX) clearly visible (Figs 12, 29). Anal fringe formed by 35–43 dorsal and 37–45 ventral setae. Dimensions: TW, 0.44–0.48; POW, 0.34–0.36; HL, 0.27– 0.3; PW, 0.31–0.35; MW, 0.59–0.68; AW, 0.71–0.80; ANW, 0.20–0.23; TL, 1.51–1.70.

Male (n = 12). As in Fig. 30. Hypopharyngeal sclerites weakly developed. Length of dorsal head seta (DHS) 10, 0.100–0.120; DHS 11, 0.090–0.100; ratio DHS 10/11, 1.00–1.22. Labial setae 5 (ls5) 0.07–0.08 long, lateroventral fringe with 8–9 setae. Gula with 3–5 setae on each side. Pronotum with 6 setae on posterior margin and 3 short spiniform setae at each lateral corner. First tibia with 3 outer ventro-lateral and 3 dorso-lateral setae. Metanotum not enlarged with 4–7 marginal setae; metasternal plate with 6–7 setae; metapleurites with 2–3 short spiniform strong setae. Femur III with 12–16 setae in ventral setal brush. Abdominal segments with well-defined median gap in each row of tergal setae. Tergal setae: I, 4; II, 7–11; III, 9–12; IV, 8–11; V, 7–9; VI, 6–8; VII, 4–6; VIII, 4. Longest tergocentral seta on segment II is relatively short (0.13–0.19). Postspiracular setae: extremely short on I, long on II, IV and VIII (0.31–0.42), shorter on VII (0.16–0.28), and shortest on III, V and VI (0.12– 0.21). Inner posterior seta of last tergite 0.02–0.03 long; short lateral marginal seta 0.02–0.03 long. Pleurites with only short spine-like setae; pleural setae: I, 2; II, 4–6; III–V, 5–7; VI, 4–6; VII, 4; VIII, 3. Pleurite VIII with inner setae (0.04–0.05) as long as outer (0.03–0.05). Anterior margin of sternal plate II with a medial notch. Sternal setae: I, 2–3; II, 4–5 in each aster—aster setae length: s1, 0.09–0.11; s2, 0.06–0.09; s3, 0.04–0.05; s4, 0.02–0.03— with 14–19 marginal setae between asters, and 4–9 medioanterior setae; III, 20–30 marginal setae; IV, 28–44 marginal setae (2–6 medioanterior setae); V, 36–51 (4–8); VI, 35–48 (5–7); VII, 22–33 (1–8); VIII, 35–50 (4–8). With 8–9 ventral and 3–5 dorsal anal setae. Genitalia as in Fig. 22; inner posterior arms of basal plate rounded (see Clay 1968: 207). Dimensions: TW, 0.39–0.42; POW, 0.31–0.34; HL, 0.26–0.28; PW, 0.28–0.30; MW, 0.36–0.43; AW, 0.44–0.50; GW, 0.09–0.11; GL, 0.40–0.48; ParL, 0.06–0.07; GSL, 0.07–0.12; TL, 1.19–1.37.

Etymology. This species epithet “ hihi ” is the name of the type host in Maori language (Checklist Committee 2010: 356), and is used here as a noun in apposition.

Type material. Ex Notiomystis cincta: Holotype ♀, Mount Bruce, Wairarapa, N.Z., 20 Dec. 1980 [bird hatched in captivity from parents transferred from Little Barrier Island] (MONZ AI. 033098). Paratypes: 1♂, same data as for the holotype (MONZ AI.017060); 6♂, 7♀, Little Barrier Island, N.Z., 18 Feb. 1979, C.R. Veitch (NZAC); 12♂, 12♀, Mount Bruce, Wairarapa, N.Z., 1981, Wildlife Service [captive bird transferred from Little Barrier Island] (MONZ AI.017061; MMBC); 1♂, Little Barrier Island, N.Z., 4 Apr. 1985, C.R. Veitch (MONZ AI.017062).

Note. By the late 1880s, the stitchbird had vanished from the New Zealand mainland, with only one population surviving on Little Barrier Island. A captive breeding programme was initiated in the 1980s, with successful reintroductions of stitchbirds into other islands (Checklist Committee 2010: 284).

Remarks. The type host of Myrsidea hihi, Notiomystis cincta, was placed in the family Meliphagidae until recently, but was transferred to a new monotypic family, Notiomystidae, based on DNA studies, which also showed a closer relationship of this family with the Callaeidae (Checklist Committee 2010: 283). Considering that there are no records of Myrsidea lice from the Callaeidae (see Pilgrim & Palma 1982: 28; Price et al. 2003: 337) and that Myrsidea hihi is morphologically closest to M. novaeseelandiae, we can speculate that there has been a host-switch of Myrsidea lice between the hosts of these two species. Furthermore, if there was a host-switch, we believe that it was more likely from a meliphagid species to Notiomystis or its ancestor because two different genera of New Zealand honeyeaters are parasitised by the same species of Myrsidea (see above).

Considering that Notiomystis cincta, the single host of Myrsidea hihi, is classified as a “Nationally Vulnerable” species in regard to its conservation status (Robertson et al. 2013: 11), thus this louse should also be regarded in the same category.