Oritoniscus flavus est un isopode terrestre de taille moyenne à faible (max 7 mm) de coloration foncée à nuances violacées (la limite du pleurépimère étant généralement plus claire), les téguments sont lisses et brillants. Il porte un unique ocelle noir, de grande taille et le flagelle est formé de 5 articles indistincts. Son nom, flavus provient de la coloration qu'il prend une fois alcoolisé.
Détermination :
La détermination des Oritoniscus est chose ardue. Le genre se reconnaît à l'exopodite du premier pléopode échancré et flanqué d'une longue tige. La différenciation spécifique est délicate et repose sur l'examen du caractère sexuel mâle, la plupart des espèces étant très proches les unes des autres notamment O. violaceus Dalens, Rousset & Fournier, 1996 et O. intermedius Vandel, 1957.
Espèces proches :
Autres espèces du genre
Période d'observation :
Espèce visible toute l'année
Biogéographie et écologie :
O. flavus est une espèce humicole, particulièrement hygrophile. Elle fréquente les bords de ruisseaux et rivières, les forêts alluviales et marécages. Originaire des Pyrénées, l'espèce s'est répandue en France et en Irlande et a récemment colonisé l'Angleterre et l'Ecosse (Sivell & Gregory, 2015)
Sivell D., Gregory S. (2015). ORITONISCUS FLAVUS (BUDDE-LUND, 1906) – A WOODLOUSE NEW TO SCOTLAND (ISOPODA: ONISCIDEA: TRICHONISCIDAE).Bulletin of the British Myriapod & Isopod Group, Volume 28 (2015)
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.