Porcellionides rufocinctus ( Dollfus, 1892 )

Cifuentes, Julio & Da Silva, Luís P., 2024, Revision of the genus Porcellionides Miers, 1877 (Isopoda: Porcellionidae) in the Ibero-Balearic region, European Journal of Taxonomy 939, pp. 1-51 : 36

Porcellionides rufocinctus ( Dollfus, 1892)

Metoponorthus rufocinctus Dollfus, 1892: 184 .

Remarks

Porcellionides rufocinctus was described by Dollfus (1892) in his work on terrestrial isopods of Spain. The description was based on a male specimen deposited in the Museo Nacional de Ciencias de Madrid (MNCN), collected by Bolívar in Villa Rutis, officially known as Santa María de Rutis, belonging to the municipality of Culleredo in the province of Coruña. Later, the same author (1893) added another locality for the species, San Roque, situated close to the first location and within the municipality of Coruña in the same province. Within the MNCN collection, there is a specimen with the following data: “Coruña, Villa Rutis, 1893, 1 male, Bolívar, MNCN 20.04/11518”. Although the date of this specimen does not match Dollfus’s original description (1892), the remaining data is consistent. This specimen was stored with the code MNCN 20.04/7895, former number 86, alongside specimens of Oniscus asellus Linnaeus, 1758 , Porcellio dilatatus Brandt, 1833 , P. herminiensis Vandel, 1946 , and P. scaber Latreille, 1804 . Currently, the specimen has undergone discoloration due to its extended preservation period in alcohol. However, we identified it as Porcellionides sexfasciatus ( Budde-Lund, 1885) based on the exopod of the pleopod I.

The original description of P. rufocinctus by Dollfus (1892) followed the common approach of the time, focusing on the coloration and morphology of the antennae, cephalon, pereon, pleon, telson, and uropods. In closely related species, these characters often prove insufficient for establishing specific identity. Absent are mentions of other now significant characters, such as pleopod and pereopod morphology, as well as certain integumentary characters like glandular fields or scale-setae. Nonetheless, Dollfus (1982) provided the following description: oval body, quite convex, pleon noticeably retracted (the body shape is exactly that of Philoscia muscorum ); cephalon with a frontal line finely but distinctly bordered, lateral lobes very short and forehead almost flat; antennae reaching approximately half the body length, flagellum segments equal. Dollfus (1983) observed regarding the San Roque specimens that their coloration resembles that of P. sexfasciatus but P. rufocinctus is cleary distinguished by the flat forehead and the much shorter pleotelson. All these characters could also correspond to P. molleri , as mentioned in the description provided above, as well as other species within this genus, and even certain specimens of P. sexfasciatus . The latter aligns with our analysis of the specimen from Villa Rutis.

Therefore, at least for now, we classify this as species inquirenda, because it is not possible to definitively differentiate it from the other species of Porcellionides .