Les Cercyon sont de petits Hydrophilidae surtout terrestres, mais semi-aquatiques pour quelques uns. C. granarius appartient à ces derniers. Noir en grande partie, rougeâtre à l'apex et de forme très convexe, il se reconnait aux palpes maxillaires brun souvent foncé, aux élytres assez brillants et réticulés avec les stries fortement ponctuées en arrière, aux interstries plans à ponctuation peu visible postérieurement, à l'apophyse mésoventrale séparée du métaventrite et guère deux fois plus longue que large.
Détermination :
Délicate, difficile sur photo d'ensemble.
Espèces proches :
C. granarius peut être confondu avec les autres espèces du sous-genre Cercyon possédant des élytres réticulés. Ces taxons se distinguent cependant par leur aspect beaucoup plus terne, parfois aussi par des interstries élytraux plus ou moins convexes postérieurement ou par l'apophyse mésoventrale en contact avec le métaventrite.
Période d'observation :
Adulte rencontré principalement au printemps et en été.
Biologie-éthologie :
Bord des eaux stagnantes ou prairies humides, en terrain plutôt ouvert, dans les matières végétales en décomposition.
Biogéographie et écologie :
Espèce plutôt rare, trouvée en exemplaires isolés ou peu nombreux, le plus souvent à basse altitude au Royaume-Uni, en France, Italie et Europe centrale.
Queney P. et Prévost P. 2021. Clé d'identification des Coléoptères aquatiques de France métropolitaine Myxophaga, Polyphaga Hydrophiloidea (adultes). Tome 1.
The map presents a summary at the 10 x 10 km grid of the observation data for the species transmitted to the SINP. These data have been subjected to validation filters.
Distribution map from the Atlas of Departmental Biodiversity and Marine Sectors program
Current distribution in metropolitan France
The map presents a reference distribution layer of the species at the scale of departments and marine sectors. The presence and absence data were established by expertise within a network of partners. This reference distribution is used in the validation process of the SINP data at the INPN level.
Distribution map from the Atlas of Departmental Biodiversity and Marine Sectors program
Certain presence
Corresponds to a report on the basis of at least one observation proved within a period of 10 years (20 years for little-known invertebrates) preceding the year and no presumption of extinction since obtaining the last data nor doubt on reproductive and implemented nature of this population. For migratory species, the presence indicated concerns areas of reproduction.
Probable presence
This status is based on one or more of the following criteria:
search of species incomplete but presence of supportive environments;
ecology of the species consistent with the hypothesis of his presence;
the last reliable sighting is older than 10 years compared to the reference date, no recent specific research and no presumption of extinction from that date [vertebrates, invertebrates and plants well studied (rhopalocera, grasshoppers, dragonflies ...)] ;
the last reliable observation being older than 20 years, no recent specific research and no presumption of extinction from that date [poorly known taxa: fungus, many invertebrates...].
Probable or certain absence
This point covers the absence, more difficult by nature to demonstrate than presence. This status is based on one or more of the following criteria:
intensive but unsuccessful targeted research;
lack of adequate environments;
unobserved species while its presence is easily detected;
unlikely presence for historical or biogeographical reasons.
This status must be assigned to a department in which the presence of the species is casual.
Absence due to a proven extinction
Particular case of absence due to a proven extinction less than a half century ago (older disappearances are treated as "no probable or definite").
No information
In the state of knowledge, we can not comment on the presence or absence in the current department. This is the default status when not comprised in one of the previous categories or whenever there is doubt.
French Version
