Fatio's Whitefish

description

Description. General appearance is shown in Figure 6. Morphological and meristic characters of both sexes can be found in Table 5 and Suppl. material 1: Table S 6 and first- and second-best ratios for both sexes combined can be found in Tables 10, 11. The description is valid for both sexes and both lakes; differences between the populations of lakes Thun and Brienz are mentioned. Shape: Elongated. Slender bodied with greatest body depth anterior of the dorsal fin resulting in a slightly torpedo-like form. Dorsal and ventral profile similar and slightly arched. Dorsal and ventral profile from tip of snout to interorbital area mostly straight and then slightly convex to dorsal and pelvic fin origin respectively. Head long. Very rarely does the snout have an approx. 40 - 50 ° angle to the body axis anterior of the eye, such that the profile from the tip of the snout to the vertical projection where the anterior part of the eye crosses the dorsal profile is straight and afterwards slightly convex. Mouth thick (i. e., width of upper and lower jaw), long and often terminal and only rarely slightly sub-terminal. Snout mostly wider than deep, not strongly pronounced, since the tip of the

A taxonomic revision of the whitefish of lakes Brienz and Thun, Switzerland, with descriptions of four new species (Teleostei, Coregonidae)

diagnosis

Diagnosis. Coregonus fatioi is a medium-sized whitefish with weak pigmentation of all fins and body; light to dark green colour on the flanks above the lateral line; moderate to many pigmented small dots on the scales along the flank and the dorsum; slender, elongated and slightly torpedo-like body; long head; tip of snout is fleshy and roundish; small eye with a thin and triangular to roundish eye socket for individuals from Lake Thun and a thick and triangular shaped eye socket for individuals from Lake Brienz; many and long gill rakers.

A taxonomic revision of the whitefish of lakes Brienz and Thun, Switzerland, with descriptions of four new species (Teleostei, Coregonidae)

distribution

Distribution and notes on biology. Coregonus fatioi is found in the lakes Thun (46 ° 40 ' N, 7 ° 46 ' E) and Brienz (46 ° 43 ' N, 7 ° 57 ' E) that are connected through the river Aare at Interlaken. Based on isotopic signatures C. fatioi feeds predominantly on zooplankton (Selz 2008; Hudson 2011; Ingram et al. 2012). Stomach content analyses of specimens of C. fatioi from Lake Brienz suggest that C. fatioi feeds on a mix of zooplankton and benthic prey (Maurer and Guthruf 2005; Mueller et al. 2007). Coregonus fatioi has a moderately fast growth rate (Both lakes: Kirchhofer 1995; Bittner et al. unpublished; Lake Brienz: Mueller et al. 2007). It has to be noted that the work by Kirchhofer (1995), Maurer and Guthruf (2005) and Mueller et al. (2007) did not distinguish between all species in lakes Thun or Brienz and thus lumped different species together into few groups. Maurer and Guthruf (2005) and Mueller et al. (2007) differentiated between " small-type " and " large-type " whitefish based on cohort-specific threshold values for length-at-age. Based on morphology and ecology Kirchhofer (1995) differentiated in Lake Thun between " Albock " (comprising most likely of C. alpinus, C. s

A taxonomic revision of the whitefish of lakes Brienz and Thun, Switzerland, with descriptions of four new species (Teleostei, Coregonidae)

etymology

Etymology. The name given to this species by Fatio (1890) was preoccupied by another species described by Fatio (1885). Kottelat (1997) proposed C. fatioi as a replacement name. The specific epithet fatioi is the genitive of Fatio. It was named by Kottelat (1997) after the late researcher Viktor Fatio, a zoologist from Switzerland who wrote a standard reference work on the Swiss vertebrates entitled " Faune des Vertebres de la Suisse Partie 1 - 3 " and in which he also described part of the whitefish species diversity of Switzerland.

A taxonomic revision of the whitefish of lakes Brienz and Thun, Switzerland, with descriptions of four new species (Teleostei, Coregonidae)