Macrourus
Creators: name: Gon, Ofer
name: Miya, Tshoanelo
name: Mcmillan, Peter
name: Leslie, Robin
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Gadiformes
Macrouridae
Macrourus

description: Key to species of southern hemisphere Macrourus
Notes:
*Based on the material examined for this study; see Table 1 for the size range of each studied species.
*The couplets in the key use a combination of characters because single characters were mostly not useful for distinguishing the species.
*Scales series length = length of a series of 4 scale rows (or their pockets) measured below the first dorsal fin, from the centre of the lateral line scale ventrally (Fig. 1)
1a. Count of scales (pockets) in a diagonal row from anal fin origin up to lateral line (not including that scale) 30 or more (30–45); scale series length 11–22% HL; canal of lateral line scales below first dorsal fin flanked by low rounded ridges, that either lack or have one small spinule (Fig. 5 a–c)...................................................................... 2
1b. Count of scales (pockets) in a diagonal row from anal fin origin up to lateral line (not including that scale) less than 30 (19–26); scale series length 17–28% HL; canal of lateral line scales below first dorsal fin flanked by steep ridges bearing strong spinules on one or both sides of the canal of each scale (Fig. 5 d–f)..................................................... 3
2a. Pelvic-fin rays 8 (rarely 7 or 9); body scales between first dorsal fin and lateral line with median ridge bearing up to 9 spinules; scale area above and below median ridge with weak ridges sometimes bearing 1–3 spinules (Fig. 4a, b)........... M. caml
2b. Pelvic-fin rays 9 (rarely 10); body scales between first dorsal fin and lateral line with median ridge bearing up to about 5 spinules; ridges above and below median ridge usually absent, but spineless when present (Fig. 4c)............. M. whitsoni
3a. Underside of head with irregular series of small scales extending from below preopercle to below eye and posterior part of lower jaw (Fig. 8e, f); area above and below median ridge of body scales between first dorsal fin and lateral line always with spinules either singular or in smaller ridges (Fig. 4d); pyloric caeca 13–20............................... M. carinatus
3b. Underside of head, including area below suborbital ridge and lower jaw (excluding isthmus) scaleless, or with few scales posteriorly (Fig. 8g, h) (check by running a finely pointed metal object or probe along skin); area above and below median ridge of body scales between first dorsal fin and lateral line with several rounded, usually spineless ridges (Fig. 4e, f); pyloric caeca 9–16.................................................................................... M. holotrachys
description: Published as part of Gon, Ofer, Miya, Tshoanelo, Mcmillan, Peter & Leslie, Robin, 2021, The distributionof fourspeciesof thegenus Macrourus (Gadiformes: Macrouridae) from the Southern Ocean based on samples from the toothfish longline fishery, pp. 105-116 in Zootaxa 4903 (1) on page 115, DOI: 10.11646/zootaxa.4903.1.6, http://zenodo.org/record/4422761