Schizosairhynchus erysichthoni Gustafsson & Bush, new species

(Figs 463–469)

Type host. Aplonis metallica metallica (Temminck, 1824) — metallic starling. Type locality. Morobe District, Papua New Guinea.

Other host. Aplonis metallica nitida (Grey, 1858) — metallic starling.

Diagnosis. Male Schizosairhynchus erysichthoni n. sp. is separated from the other two species in the genus by the following characters: distal mesosome relatively slender in Sc. erysichthoni (Fig. 467), but much wider in Sc. minovenator n. sp. (Fig. 474) and Sc. philippensis (the distal mesosome of undescribed species of Schizosairhynchus n. gen. on Aplonis spp. are similar to that of Sc. erysichthoni; unpub. data); ventral sclerite does not extend distal to gonopore in Sc. erysichthoni (Fig. 467) but does extend lateral and distal to gonopore in the other two species (Fig. 474); rugose nodi small, oblong in Sc. erysichthoni (Fig. 467) but larger and rounded in the other two species (Fig. 474); pmes situated antero-lateral to rugose nodi in Sc. minovenator (Fig. 474) and Sc. philippensis, but postero-lateral to nodi in Sc. erysichthoni (fig. 467); thickening of anterior margin of proximal mesosome transversally continuous in Sc. minovenator (Fig. 474) and Sc. philippensis but only lateral in Sc. erysichthoni (Fig. 467). Note that in the original description of Sc. philippensis (Tandan & Kumar 1969: fig. 7), neither the ventral sclerite, the rugose nodi, the pmes, or the anterior thickening of the proximal mesosome is illustrated. Yet, even in this illustration, the shape of the mesosome and the presence of the small paired nodi just distal to the gonopore separates this species from Sc. erysichthoni .

Female Schizosairhynchus erysichthoni separated from the other two species in the genus by the partial crosspiece of the subgenital plate (Fig. 469); no such cross-piece exists in Sc. minovenator (Fig. 476), and in Sc. philippensis the subgenital plate not reach the vulval margin. Both Sc. minovenator (Fig. 476) and Sc. philippensis have more than 22 vss on each side, whereas Sc. erysichthoni (Fig. 469) only has 12–16.

Description. Both sexes. Head shape, structure, and chaetotaxy as in genus description and Fig. 465. Lateral margins of dorsal anterior plate shallowly convex. Thoracic and abdominal segments as in genus description and Figs 463–464. Tergopleural and sternal plates light brown; antero-lateral corners of tergopleurites and pleurites darker.

Male. Abdominal chaetotaxy as in Table 2 and Fig. 463. Sternal plates IV–VI and subgenital plate with small accessory plates laterally (Fig. 463); 2 accessory plates lateral to subgenital plate on each side. Basal apodeme (Fig. 466) rounded rectangular to trapezoidal. Proximal mesosome quadratic, anterior margin flat to slightly concave, with distinct thickenings laterally. Gonopore (Fig. 467) ventral, narrowly open distally, with pair of slender sclerites attached to anterior margin. Mesosomal lobes wide, fused distally, with distal margin thickened. Rugose nodi slight, flattened. Ventral sclerite (VS in Fig. 467) does not extend distal to gonopore; sclerite not thickened anteriorly; 2 ames microsetae on each side of ventral sclerite; 2 pmes microsetae on each side, postero-lateral to rugose nodi. Parameral heads (Fig. 468) roughly triangular. Parameral blades gently curved, somewhat irregular, tapering slowly, not extended distally; pst1–2 as in genus description. Measurements ex Aplonis metallica metallica (n = 15): TL = 1.25–1.37 (1.31); HL = 0.45–0.51 (0.47); HW = 0.45–0.49 (0.46); PRW = 0.26–0.30 (0.28); PTW = 0.39–0.44 (0.41); AW = 0.54–0.68 (0.61). Ex A. m. nitida (n = 5 except n = 4 for AW, TL): TL = 1.31–1.38; HL = 0.45–0.49; HW = 0.45–0.49; PRW = 0.27–0.31; PTW = 0.40–0.44; AW = 0.59–0.67.

Female. Abdominal chaetotaxy as in Table 2 and Fig. 464. Sternal plates wide (Fig. 464); sternal plates III–VI and subgenital plate with small accessory plates laterally. Subgenital plate roughly triangular, but anterior margin convex (Fig. 469); distally subgenital plate reaches vulval margin and expands into partial cross-piece. Vulval margin (Fig. 469) bulging slightly medianly, with 5–7 long, slender vms on each side, and 12–16 short, thorn-like vss on each side; 7–8 short, slender vos; proximal 4–5 vos scattered on subgenital plate, and distal 3 vos approaching vss. Measurements ex Aplonis metallica metallica (n = 17 except n = 16 for HW and n = 15 for AW): TL = 1.49–1.74 (1.58); HL = 0.48–0.55 (0.51); HW = 0.47–0.54 (0.50); PRW = 0.29–0.34 (0.31); PTW = 0.39– 0.49 (0.45); AW = 0.62–0.82 (0.70). Ex A. m. nitida (n = 6 except n = 4 for AW and n = 3 for TL): TL = 1.54–1.62; HL = 0.47–0.52; HW = 0.47–0.52; PRW = 0.29–0.32; PTW = 0.43–0.47; AW = 0.68–0.72.

Etymology. The species epithet is in honour of Erysichthon, the king of Thessaly who, after cutting down a sacred grove of trees devoted to Demeter, the goddess of harvests, was cursed to have Limos, the goddess of starvation, placed in his stomach. This drove him to insatiable hunger, and he eventually ate himself. While we do not suggest that this regularly happens to Schizosairhynchus erysichthoni (for the days of the Old Gods seem to be over), it is a fitting name for a louse species that is prepared to eat a “metallic” starling.

Type material. Ex Aplonis metallica metallica: Holotype ♂, 12 miles NE of Lae, elev. 100 ft, Silium Village, Bupu River, Morobe District, Papua New Guinea, 20 Apr. 1970, A.B. Mirza, BBM-NG-98658 (BPBM) . Paratypes: 3♂, 5♀, same data as holotype (BPBM); 1♂, 1♀, same data as holotype, except BBM-NG-98656 (BPBM); 1♀, 20 km N of Bulolo, elev. 1900 ft, Sum Sum, Morobe District, Papua New Guinea, 11 Feb. 1963, H. Clissold, BBM-NG-21215 (BPBM) ; 1♀, Sindeada, elev. 10 m, Milne Bay District, Papua New Guinea, 1 Apr. 1965, P.J. Shanahan, BBM-NG-24532 (BPBM) ; 1♀, Jumbora Plantation, elev. 25 m, Popondetta, Northern District, Papua New Guinea, BBM-NG-24925 (BPBM) ; 5♂, 8♀, Popondetta, elev. 200 m, Northern District, Papua New Guinea, 4 Sep. 1963, P.J. Shanahan, BBM-NG-28698, 28700, 28705, 28707 (BPBM) ; 2♂, Popondetta, elev. 60 m, Northern District, Papua New Guinea, 7 Sep. 1963, P.J. Shanahan, BBM-NG-28706 (BPBM) ; 3♂, 3♀, Soputa River, elev. 200 ft, Northern District, Papua New Guinea, 28–29 Sep. 1963, H. Clissold, BBM-NG-29718, 29850 (BPBM) ; 1♂, 2♀, same locality and collector as previous, 4–5 Oct. 1963, BBM-NG-29838 (BPBM); 3♂, 8♀, Zenani, elev. 400 ft, Northern District, Papua New Guinea, 11 Oct. 1963, H. Clissold, BBM-NG-29946–7, 29950–1, 29954–5 (BPBM) ; 2♂, Ahola, elev. 150 ft, Northern District, Papua New Guinea, 7 Oct. 1963, H. Clissold, BBM-NG-29879, 29949 (BPBM) ; 2♂, 1♀, Cape Killerton, elev. 10 ft, Northern District, Papua New Guinea, 20 Oct. 1963, H. Clissold, BBM-NG-29728 (BPBM) ; 2♂, Ambunti, elev. 200 ft, West Sepik District, Papua New Guinea, 7 May 1963, P. Temple, BBM-NG-22563, BBM-NG-22565 (BPBM) .

Ex Aplonis metallica nitida: 3♂, 4♀, Broala, elev. 20 m, Santa Isabel Island, Solomon Islands, 24 Aug. 1964, P.J. Shanahan, BBM-SI-24282, 24210 (BPBM) ; 2♂, 3♀, elev. 20 m, Malaita Island, Solomon Islands, 29 Jun. 1964, P.J. Shanahan, BBM-NG-24074 (BPBM) .

Remarks. We found few differences between specimens from the two host subspecies. Material from A. metallica nitida from Malaita Island is generally darker than that from other localities, and there are fewer vss (12– 14 compared to 13–16 in material from A. metallica metallica). Many females from A. m. nitida have 6 mediansubmedian pairs of macrosetae on tergopleurites III–IV instead of the 5 pairs in material from A. m. metallica . Amore thorough study of the Schizosairhynchus from Aplonis starlings is needed to determine the significance of these differences. Conservatively, we treat material from both host subspecies as one species.