Zug Whitefish

description

Description. Shape: Body elongated and slender. Greatest body depth anterior of the dorsal fin. Ventral profile and dorsal profile similar and slightly arched. Dorsal and ventral profile from tip of snout to interorbital mostly straight and then slightly convex to dorsal and pelvic fin origin respectively. Head long. Snout long and tip of snout if slightly pointed resulting in a not strongly pronounced rostral plate. Mouth long and terminal. Large eye with a subtle sickle cell-shaped (seldom roundish) eye-socket. Pectoral fin long and tapered. Caudal peduncle moderately stout. Meristics: Many and long gill rakers. Colour: Pigmentation of fins and body weak in live specimens. Pectoral fin transparent and pelvic and anal fin mostly transparent. Pectoral fin very rarely pigmented at the distal part of the fin and the anal and pelvic fin rarely moderately pigmented at the median to distal parts of the fin. Dorsal, caudal and adipose fin moderately pigmented. Silvery appearance along the flanks. Dorsally above the lateral line the silvery appearance changes to a pale olive-brown. Pre-operculum and operculum with one black spot on the lower margin of the pre-operculum. Preserved specimen

A taxonomic revision of ten whitefish species from the lakes Lucerne, Sarnen, Sempach and Zug, Switzerland, with descriptions of seven new species (Teleostei, Coregonidae)

diagnosis

Diagnosis. Coregonus zugensis is a small whitefish species with weak pigmentation of all fins and body; pale olive-brown colouration on the flanks above the lateral line; elongate slender body (body depth: 22.5 - 25.9 % SL, mean = 24); large eye (eye diameter: 19.7 - 25.3 % SL, mean = 22.9) with a subtle triangular eye socket (1.6 - 5.9 % HL, mean = 3.8); many and long gill rakers (longest gill raker: 11.2 - 17.7 % HL, mean = 14.3; total gill raker number: 33 - 40).

A taxonomic revision of ten whitefish species from the lakes Lucerne, Sarnen, Sempach and Zug, Switzerland, with descriptions of seven new species (Teleostei, Coregonidae)

distribution

Distribution and notes on biology. Coregonus zugensis occurred in Lake Zug and is extinct today (this is discussed in more detail in the Suppl. material 1: paragraph 4). Fatio (1885) mentions in a table three whitefish species for lake Zug ' Balchen', ' Albock', and ' Albeli', but later Fatio (1890) only mentions two whitefish species for Lake Zug, namely the ' Balchen' (Coregonus schinzii helveticus var. zugensis) and the ' Albeli-Albock' (Coregonus wartmanni compactus). Interestingly, Wagler (1937) noted two species to be present in Lake Zug with a remark that a third species may exist, but that its status is uncertain. Fatio (1890) does mention that fishermen have suggested that among the ' Albeli-Albock' there are individuals that are smaller and spawn later in the year, which they refer to as ' Albeli', when compared to the individuals they refer to as ' Albock' that are slightly larger and spawn earlier in the year. However, the specimens that Fatio (1890) could examine did not warrant this distinction and thus he suggested to group the ' Albeli' and ' Albock' under the name ' Albeli-Albock'. Fatio (1890) suggested that the ' Albeli-Albock' spawn in mid-September to mid-Octob

A taxonomic revision of ten whitefish species from the lakes Lucerne, Sarnen, Sempach and Zug, Switzerland, with descriptions of seven new species (Teleostei, Coregonidae)

etymology

Etymology. The specific name zugensis refers to Zug, a city that gave its name to Lake Zug. An adjective.

A taxonomic revision of ten whitefish species from the lakes Lucerne, Sarnen, Sempach and Zug, Switzerland, with descriptions of seven new species (Teleostei, Coregonidae)