Alpine Whitefish

description

Description. General appearance is shown in Figure 5. Morphological and meristic characters of both sexes can be found in Table 4 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: Generally deep bodied with greatest body depth anterior of the dorsal fin. Dorsal profile strongly arched compared to ventral profile such that the dorsal profile from the tip of snout to the anterior origin of dorsal fin is moderate to strongly convex. Ventral profile slightly arched such that almost straight or slightly convex from the interorbital area to the pelvic fin origin. Head short. Mouth thin (i. e., width of upper and lower jaw), short and sub-terminal. Rostral plate pronounced and almost equally wide as deep resulting in an almost square shape. Tip of the snout often blunt. Small eye, which is less pronounced in specimens from Lake Brienz. Eye-socket thick and triangular (i. e., sickle-shaped). Pectoral fin moderately tapered. Dorsal fin long with the anterior unbranched ray of the ere

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

diagnosis

Diagnosis. Coregonus alpinus is a large whitefish with strong pigmentation of all fins and the body; greenish blue colour on the flanks above the lateral line; moderate to many pigmented small dots on the scales along the flank and the dorsum; deep bodied; truncated blunt snout; short head; sub-terminal mouth; small eye with a thick and triangular-shaped eye socket; short and stout caudal peduncle; few and short 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 alpinus 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. Coregonus alpinus feeds predominantly on benthic prey and parts of the year on zooplankton (stomach content for Lake Brienz: Maurer and Guthruf 2005; Mueller et al. 2007; isotopic signature for both lakes: Selz 2008; Hudson 2011; Ingram et al. 2012) and has a rapid growth rate (Lake Brienz: Mueller et al. 2007; both lakes: Kirchhofer 1995; Bittner et al. unpublished). It has to be noted that the stomach content and isotopic work did not distinguish between all species in lakes Thun or Brienz and thus in some cases lumped different species together into few groups. The stomach content work by 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. steinmanni and C. acrinasus), " Brienzlig " (comprising most likely of C. albellus

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

materials_examined

Material examined. Lectotype. MHNG- 717.045, Switzerland, Lake Thun (46 ° 40 ' N, 7 ° 46 ' E), 283 mm SL, sex unknown. Non-types. NMBE- 1077241 - 1077261, Switzerland, Lake Thun (46 ° 40 ' N, 7 ° 46 ' E), N = 21, 210 - 364 mm SL; NMBE- 1059817; 1059821; 1077134, NMBE- 1077110 - 1077115, Switzerland, Lake Brienz (46 ° 43 ' N, 7 ° 57 ' E), N = 9, 147 - 290 mm SL.

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