Catharacta skua hamiltoni Hagen, 1952

Johannessen, Lars Erik & Lifjeld, Jan T., 2022, Type specimens of birds in the Natural History Museum, University of Oslo, Norway, Zootaxa 5150 (4), pp. 451-486 : 460-462

Catharacta skua hamiltoni Hagen, 1952

Birds of Tristan da Cunha. Results of the Norwegian scientific expedition to Tristan da Cunha 1937–1938, No. 20: 135–145.

Current name: Stercorarius antarcticus hamiltoni ( Hagen, 1952)

Syntype NHMO-BI-67601 [I026282]; Study skin; Imm. F; Yngvar Hagen (80), 31 January 1938; SHN 2: Nightingale; 37.427° S, 12.478° W; 13a.

Syntype NHMO-BI-67602 [I026283]; Study skin; Ad. M; Yngvar Hagen (260), 26 February 1938; SHN: Inaccessible; 37.300° S 12.673° W; 13b.

Syntype NHMO-BI-67603 [I026284]; Study skin; Juv. F; Yngvar Hagen (57), 20 January 1938; SHN: Inaccessible; 37.300° S 12.673° W; 13c.

Syntype NHMO-BI-67604 [I026285]; Study skin; Ad. M; Yngvar Hagen (3), 16 December 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W; 14a.

Syntype NHMO-BI-67605 [I026286]; Study skin; Ad. F; Yngvar Hagen (75), 25 January 1938; SHN: Tristan da Cunha; 37.105° S 12.278° W ; 14b.

Syntype NHMO-BI-85384; Study skin; Ad. F; Yngvar Hagen (2), 16 December 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W ; 14c.

Syntype NHMO-BI-92659; Blown eggshell; Egg; Yngvar Hagen (352), 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W ; 5a.

Syntype NHMO-BI-92660; Blown eggshell; Egg; Yngvar Hagen (356), 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W ; 5b.

Syntype NHMO-BI-92661; Blown eggshell; Egg; Yngvar Hagen (353), 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W ; 5c.

Syntype NHMO-BI-92662; Blown eggshell; Egg; Yngvar Hagen (357), 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W ; 5d.

Syntype NHMO-BI-92663; Blown eggshell; Egg; Yngvar Hagen (358), 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W ; 5e.

Syntype NHMO-BI-92664; Blown eggshell; Egg; Yngvar Hagen (355), 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W; 5f.

Syntype NHMO-BI-92665; Blown eggshell; Egg; Yngvar Hagen (354), 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W ; 5g.

Syntype NHMO-BI-92666; Blown eggshell; Egg; Yngvar Hagen (351), 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W ; 5h.

Syntype NHMO-BI-92668; Blown eggshell; Egg; Yngvar Hagen (350), 1937; SHN: Tristan da Cunha; 37.105° S 12.278° W ; 5i.

Remarks: Hagen (1952) based his description of this subspecies on a total of nine birds examined in the field, but only six of them were skinned and preserved. He did not assign any holotype among these, and all nine birds must therefore be considered syntypes. In addition, he also explicitly mentioned and provided average measurements for nine eggs. According to Article 72.5.1 of the Code ( International Commission on Zoological Nomenclature 1999), ’…any part of an animal… ’ is eligible to be a name-bearing type, and we therefore consider also these nine eggs to be part of the type series for this taxon. Dimensions of all nine eggs, based on measurements made by L.E.J., are provided in Table 3 ; the average dimensions of these (50.6 x 69.7 mm) match exactly those provided by Hagen (1952). All extant syntypes (i.e. six skins and nine eggs) are present in the NHMO collection.

2 SHN: Saint Helena, Ascension and Tristan da Cunha

The skins are all labelled with metal tags with the collector’s field number embossed into them ( Figure 4 ), while the eggs are labelled with the field number written with pencil directly on their surface ( Figure 5 ). One of the eggs (NHMO-BI-92664) is cracked and has previously been attempted to be repaired.

Figures

FIGURE 4. Labels (metal tags) of type specimens in the NHMO Bird Collection of Catharacta skua hamiltoni Hagen, 1952 (all collector’s labels). a) NHMO-BI-67601; b) NHMO-BI-67602; c) NHMO-BI-67603; d) NHMO-BI-67604; e) NHMO-BI- 67605; f) NHMO-BI-85384.

FIGURE 5. Eggs in the NHMO Bird Collection included as types of Catharacta skua hamiltoni Hagen, 1952 (labelled directly on the eggs by the collector). a) NHMO-BI-92659; b) NHMO-BI-92660; c) NHMO-BI-92661; d) NHMO-BI-92662; e) NHMO-BI-92663; f) NHMO-BI-92664; g) NHMO-BI-92665; h) NHMO-BI-92666; i) NHMO-BI-92668. All eggs are shown to the same scale.