''Deroceras cecconii'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of air-breathing land

slug Slug, or land slug, is a common name for any apparently shell-less Terrestrial mollusc, terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced ...

, a

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on o ...

pulmonate Pulmonata or pulmonates is an informal group (previously an order, and before that, a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group inclu ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

in the family Agriolimacidae. Although it was long considered a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''

Deroceras panormitanum ''Deroceras panormitanum'' is a species of air-breathing land slug, a terrestrial pulmonate gastropod mollusc in the family Agriolimacidae. ''Deroceras panormitanum'' ''sensu stricto'' ("in the strict sense") is common on Sicily and Malta, but ...

'', a 2020 article establishes that it is a distinct species widely distributed in the central part of the Italian peninsula. It is also known as an introduction at one site in eastern Germany.

Taxonomic history

Deroceras_cecconii_genitalia_Figure_4_Pollonera_1896

In 1896, Carlo Pollonera described the slug species ″''Agriolimax Cecconii''″ on the basis of material supplied to him by the entomologist Giacomo Cecconi (1866–1941). Cecconi found the species where he worked in the forest of

Vallombrosa Vallombrosa is a toponym which indicates both a forest and a ''frazione'', located within this forest, in the territory of the Reggello, Commune of Reggello, in the Metropolitan City of Florence, in the Italy, Italian region of Tuscany. The villag ...

in the hills east of

Florence Florence ( ; ) is the capital city of the Italy, Italian region of Tuscany. It is also the most populated city in Tuscany, with 362,353 inhabitants, and 989,460 in Metropolitan City of Florence, its metropolitan province as of 2025. Florence ...

, Italy. Subsequent 20th-century workers considered the description inadequate or that the name should be considered a synonym of ''Deroceras panormitanum''. More recently it was recognised that the latter name had been applied to more than one species. New collections from the type locality of ''D. cecconii'' have now established that the animals described and figured by Pollonera are indeed distinct, based on

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

sequences and mating behaviour as well as genital anatomy. Pollonera also described a subspecies ″''Agriolimax cecconii'' var. ''ilvatica''″ from the island of Elba, differing in its genital anatomy. The status of this taxon is unclear.

Description

Adults are of the order of 3 cm long. The skin is thin and fairly transparent, often blackish, but brown and pale forms also occur. The mucus is colourless. Thus the external appearance is similar to that of various other ''Deroceras'' species, such as '' D. invadens'', '' D. panormitanum'' and '' D. sturanyi''. An indicative but not consistent distinguishing character is a ″pinched″ appearance of the tip of the tail in ''D. cecconii''. Like with other ''Deroceras'' species, reliable identification requires dissecting the animal to reveal the penis. The most prominent features of the penis are the penial glands, which sit on a substantial trunk, and the penial lobe (a blind-ended pocket). Between these structures lies an indented saddle near where the vas deferens inserts. This indentation to the profile of the penis distinguishes ''D. cecconii'' from '' D. golcheri''. The penial caecum is often just a swelling, much less prominent than that of ''D. invadens'' or ''D. panormitanum''.

Distribution and ecology

''Deroceras cecconii'' occurs widely in the central part of the Italian peninsula, including at one locality in the

Republic of San Marino A republic, based on the Latin phrase ''res publica'' ('public affair' or 'people's affair'), is a state in which political power rests with the public (people), typically through their representatives—in contrast to a monarchy. Although a ...

. Also one population, presumably an introduction, lies 700 km to the north in the town of

Ostritz Ostritz (, , ; Polish: ''Ostrowiec'' ) is a town in the district Görlitz, in Saxony, in eastern Germany. It is situated on the border with Poland, on the left bank of the Lusatian Neisse, 16 km south of Görlitz. It is located next to the ...

on the eastern border of Germany. The species typically is found under discarded rubbish and in leaf litter, in both synanthropic habitats and natural woodland. It often co-occurs with ''D. invadens''. ''Deroceras cecconii'' is known to be adult in spring; its growth rate in the laboratory suggests that it may go through several generations in a year.

References

External links

''Agriolimax cecconii'' taxon page
at

Animalbase AnimalBase is a project brought to life in 2004 and is maintained by the University of Göttingen, Germany. The goal of the AnimalBase project is to digitize early zoological literature, provide copyright-free open access to zoological works, and p ...

Two videos of mating behaviour
{{Taxonbar, from=Q104835212 Agriolimacidae Gastropods described in 1896