Classification / Names
Common names | Synonyms | Catalog of Fishes (gen., sp.) | ITIS | CoL | WoRMS | Cloffa
Actinopterygii (ray-finned fishes) > Osmeriformes
(Smelts) > Microstomatidae
Etymology: boreacrassicauda: Name from Latin 'boreas' for Subarctic or to the north (referring to distribution of type materials); 'crassus' for fat or stout and 'cauda' for tail (referring to the stubby caudal peduncle).
Environment: milieu / climate zone / depth range / distribution range
Marine; pelagic-oceanic; depth range 382 - 400 m (Ref. 104906). Deep-water
Countries | FAO areas | Ecosystems | Occurrences | Point map | Introductions | Faunafri
Atlantic Ocean: temperate and subarctic.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 26.8 cm SL male/unsexed; (Ref. 104906)
Morphology | Morphometrics
This species is distinguished by the following characters: a 'stubby caudal species' with PCL/PCD ratio 1.20-1.31; predorsal length <50% SL; dentition extensive, falling into high-number teeth group, often noted for the dentary resembling a closely-spaced picket fence; curved vomerine teeth; large eye, approximately 40% of HL; a large crescent of white tissue on posterior half of eye; with large circumorbitals; with concave indentation in posterior margin of operculum (opercular tube), somewhat variable between type materials; with a large
ventral strip of bioluminescent tissue associated with large scales, running from isthmus to vent, appearing dark in preservative; with large patches of distinct whitish, fatty tissue present on anterior and posterior parts of preorbital bone, elongated patch bordering all opercular bones, long strip dorsally separating cranial bones from nape, all patches fading in preservative; large and modified lateral-line scales, showing two pointed projections at posterolateral margins below adipose fin, extending several scales onto caudal fin rays; crumenal organ with relatively small accessory cartilage between fifth cerato- and epibranchial, fourth epibranchial with uncinate process, gill rakers on accessory cartilage 6-7, on fifth ceratobranchial 9-10 (total 16), epibranchial-5 + ceratobranchial-4 with 16 gill rakers in total; adipose fin is large, proximal part heavily pigmented; large pineal window present between eyes; with aphakic gap, acorn- or oval shaped; pseudobranch filaments 15-21; otoliths lanceolate, approximately 7.0 mm (3.0% SL) assembled (each broken into two), rostrum long, ventral margin denticles broad and deep, appearing highly convoluted; body colour golden-brownish, scales strongly iridescent when freshly caught, dull brown after preservation in alcohol/formaldehyde (Ref. 104906).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Poulsen, J.Y., 2015. A new species of pencil smelt Nansenia boreacrassicauda (Microstomatidae, Argentiniformes) from the North Atlantic Ocean. Zootaxa 4020(3):517-532. (Ref. 104906)
IUCN Red List Status (Ref. 120744)
CITES (Ref. 118484)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01122 (0.00514 - 0.02450), b=3.04 (2.87 - 3.21), in cm Total Length, based on all LWR estimates for this body shape (Ref. 93245
Trophic Level (Ref. 69278
): 3.4 ±0.4 se; Based on size and trophs of closest relatives
Vulnerability (Ref. 59153
): Low vulnerability (23 of 100) .