New Species of Terrestrial Isopods (Crustacea, Isopoda, Oniscidea) from Liguria and Surrounding Regions, Northern Italy

: Five new species of terrestrial isopods from Liguria and surrounding regions are described: Buddelundiella zoiai sp. n. (Buddelundiellidae), Sardoniscus marmoratus sp. n. (Oniscidae), Cylisticus poggii sp. n. (Cylisticidae), Porcellio incavatus sp. n. (Porcellionidae), and Alloschizidium segestanum sp. n. (Armadillidiidae). Buddelundiella zoiai , Cylisticus poggii and Alloschizidium segestanum were collected in edaphic environments, while Sardoniscus marmoratus and Porcellio incavatus were found in leaf litter or under not deeply embedded rocks. The diagnostic characters, the afﬁnities and the distribution of the new species are discussed.


Introduction
Liguria is a small region in the north-west of Italy, enclosed by the Ligurian Sea to the south and crossed by two distinct mountain ranges, the Ligurian Alps to the west and the Ligurian Apennines to the east.These two ranges compose a continuous chain across the region and are, respectively, linked to the Maritime Alps and the Tuscan-Emilian Apennines.Despite its limited territorial extension (5418 km 2 ), the region is of remarkable faunistic and floristic value, since it includes a great variety of environments: from littoral and dry Mediterranean habitats to meso-thermophilic deciduous woods, up to montane and Alpine habitats.Moreover, it is noteworthy in the presence of a high number of caves (more than 2000) throughout the region, especially in the western part, as reported by the Delegazione Speleologica Ligure on the speleological cadastre [1].Due to its geographic position and geoclimatic context, Liguria represents a significant biogeographic crossroads, hosting at the same time species with Tyrrhenian, Alpine or north-Apennine distribution.The westernmost portion of the region is of particular interest due to the presence of Ibero-French taxa, which are absent in the rest of the Italian peninsula [2][3][4][5][6][7][8][9].
Such a diverse set of environments makes this region suitable to host a rich fauna of terrestrial isopods, which are an ideal biological model for faunistic and biogeographical studies, due to their reduced dispersal ability and strong stenoecy.The Ligurian oniscidean fauna currently includes 97 described species, belonging to 37 genera and 17 families (unpublished data).For comparison, 78 species are recorded for Corsica, 94 for Sardinia, 103 for Sicily and surrounding islands, 131 for Tuscany, and approximately 380 for the whole of Italy [10].
In the last five years, the examination of both preserved and newly collected material has allowed us to resume the study of terrestrial isopods from this region.In this paper, we describe five new species from Liguria and surrounding regions in the families Buddelundiellidae, Oniscidae, Cylisticidae, Porcellionidae, and Armadillidiidae.

Collection, Preparation and Drawing of Specimens
The examined material comes both from museum collections and newly collected samples.The specimens were collected by hand or by litter sifting or were extracted from soil samples with the aid of Berlese-Tullgren funnels.The material was stored in 75% ethanol and identifications were based on morphological characters.The dissected specimens were mounted on slides and illustrated with the aid of a camera lucida mounted on Wild M5 and M20 microscopes.Figures were digitally drawn following the method described by Montesanto [70,71].For each new species, the material examined, etymology, description, ecology, and remarks are given.

Depositories
Studied material is deposited in the following institutions and collections, which are referred to in the text by their abbreviations: MZUF-Museo di Storia Naturale, Sezione di Zoologia "La Specola", University of Florence, Italy.

Etymology
The new species is named after our colleague and friend Stefano Zoia (Milan), who first collected material of this small Buddelundiella species.

Description
Maximum length: ♂, 1.8 mm, ♀, 2.5 mm.Body convex, able to roll up into a ball, endoantennal conglobation (Figure 1A).Color pale brown.Dorsal cuticle with sparse ovoid scale-setae (Figure 1B).Pereonites with one line of noduli laterales per side more or less on same line, distant from both lateral and posterior margins (Figures 1A and 2A).Dorsum covered with ribs and tubercles as follows (Figure 1A,C-I and Figure 2C): cephalon with 4 + 4 short longitudinal ribs and small median tubercle on posterior part of vertex; all pereonites with small median tubercle on posterior part; pereonites 1-6 with 6 lines of ribs and tubercles per side; pereonite 7 with 4 lines of ribs and tubercles per side; pleonites 4, 5 and telson with 2 paramedian tubercles.Cephalon with frontal shield slightly grooved and centrally depressed; eye small, consisting of three ommatidia.Pereonite 1 with anterolateral corner slightly protruding frontwards; posterolateral corner rounded; ventral epimeron with longitudinal thickening and lateral margin grooved (Figure 2A,B).Pereonites 2-7 with subrettangular epimera (Figure 1A).Pereonite 2 with small and rounded thickening on ventral side of epimera (Figure 2B).Pleonite 3 without epimera as in all species of Buddelundiella (Figures 1A and 2C).Telson trapezoidal, approximately twice as wide as long (Figure 2C).Antennula of three articles diminishing in length from first to third; two apical aesthetascs (Figure 2D).Antenna short and stout, fifth article of peduncle enlarged; flagellum of three articles with two aesthetascs on second article (Figure 2E).Mandibles with two free penicils in left and one in right (Figure 2F,G).Maxillula outer branch with 4 + 6 teeth and two long slender setae; inner branch with one apical and two subapical penicils, proximal one longest (Figure 2H).Maxilla with very small inner lobe bearing two thick setae; outer lobe setose with line of thick setae (Figure 2I).Maxilliped with proximal segment of palp bearing one seta, distal segment apically setose and with thick seta on outer margin; endite triangular with three strong setae on outer margin and large segmented apical penicil (Figure 2J).Uropod with quadrangular protopod; exopod inserted near medial margin, not surpassing distal margin of protopod; endopod distinctly longer than exopod (Figure 3A).
Male.Pereopod 1 without distinct sexual specializations (Figure 3B).Pereopod 7 ischium with slightly convex sternal margin; carpus slightly enlarged distally (Figure 3C).Genital papilla fusiform (Figure 3D).Pleopod 1 exopod subrectangular, approximately twice as long as wide, distal margin slightly concave; endopod of two articles, proximal article as long as but wider than distal article; distal article with thin suture on basal third, apical part triangular, striped; outer margin with thin appendix distally setose (Figure 3E).Pleopod 2 exopod trapezoidal, with rounded distal part bearing short seta; endopod with two narrow articles, distal article more than twice longer than basal one.

Ecology
Humicolous species, can also be found in edaphic environments.The examined specimens were collected by litter sifting or extracted from soil samples.Verhoeff, 1930.It differs from B. voluta in having pleonites 4 and 5 with two paramedian tubercles; from B. cataractae in the number of dorsal tubercles on the pereonites (6 + 6 + a median one instead of 5 + 5 + a median one on pereionite 1, 4 + 4 + a median one instead of 3 + 3 on pereonite 7) and on the pleonites and telson (1 + 1 on pleonites 4, 5 and telson instead of 2 + 2 only on pleonite 4); from B. borgensis, even if poorly described by Verhoeff [54] based on a single female specimen, in the number of dorsal tubercles on pereonites 2-6 (6 + 6 + a median one instead of 4 + 4) and presence of tubercles on pleonites 4 and 5; from B. insubrica in the number of dorsal tubercles on pereonite 7 (4 + 4 + a median one instead of 3 + 3) and pleonites 4 and 5 with two paramedian tubercles.The new species differs from B. armata and B. zimmeri in the less developed dorsal ornamentation, also in pereonite 7 with 4 + 4 tubercles + a median one (1 + 1 in B. armata and 2 + 2 in B. zimmeri).

Remarks
Buddelundiellidae are considered here as a separate family within Synocheta as remarked by Tabacaru and Giurginca [72].Schmalfuss [73], however, considered this taxon as a subfamily of the family Trichoniscidae closely related to the subfamily Haplophthalminae.Tabacaru and Giurginca [72] pointed out the differences with Haplophthalminae (e.g., the eye of three ommatidia in Buddelundiella, not present in any genera of this subfamily) and listed many characters, even if some not so reliable, distinguishing Buddelundiellidae from Trichoniscidae.The presence of noduli laterales in Buddelundiella species was never observed before and constitutes an additional important character.Apart from B. zoiai sp.n., this trait has also been found in B. zimmeri Verhoeff, 1930, B. cataractae Verhoeff, 1930 and B. voluta Verhoeff, 1930, examined by us, and most probably it is present in all the species of the genus.According to Schmidt [74], the noduli laterales are present only in the higher taxa of the section Crinocheta, excluding the families Olibrinidae, Detonidae, Scyphacidae and Alloniscidae, and possibly in some taxa of the family Styloniscidae (section Synocheta).The presence of noduli laterales in species of Buddelundiella could therefore represent more robust evidence suggesting the distinction of Buddelundiellidae from Trichoniscidae.

Etymology
From Latin: marmoratus = marbled.The name refers to the brown and yellow color pattern of the dorsal side of the species.

Ecology
Epigean and humicolous species, normally found in leaf litter or under not deeply embedded rocks.It can also be easily found at the entrance to caves or artificial cavities.The examined specimens were collected by hand.

Remarks
Previously to this paper, the genus Sardoniscus comprised two species: S. pygmaeus (Budde-Lund, 1885) from Corsica, Sardinia and Tuscany, and S. verhoeffi (Ferrara and Taiti, 1978) from peninsular Italy.In the shape of cephalon the new species is similar to S. pygmaeus, from which it differs in the larger size, the noduli laterales of pereonite 7 being not so eccentric and the male pleopod 1 exopod with a triangular posterior part (cfr.[75] (figs 262, 265A) and [76] (figs X.3, XI.1)).Compared to S. verhoeffi, S. marmoratus sp.n. shows a similar disposition of the noduli laterales, but it is readily distinguished by the protruding frontal lobes of the cephalon and the more developed distal part of the male pleopod 1 exopod (cfr.

Etymology
The new species is named after our colleague and friend Dr Roberto Poggi (MSNG), who collected the specimens.

Etymology
The new species is named after our colleague and friend Dr Roberto Poggi (MSNG), who collected the specimens.

Ecology
Edaphic species, can be found in the first soil layers or under deeply embedded rocks.

Remarks
The new species belongs to the nasutus-group of the genus Cylisticus, characterized by a depigmented body, reduced or absent eyes, and noduli laterales more or less on the same line [77].This group includes 17 species distributed in northern and central continental Italy, the Tuscan Archipelago, Sardinia, Corsica and in the south-eastern France.All species are endogean and can be found under deeply embedded stones with some also occurring in caves.
In the bent apical part of the male pleopod 1 endopod, Cylisticus poggii sp.n. is similar to C. caprariae

Etymology
From Latin incavatus = hollow, concave.The name refers to the deeply concave sides of the posterior margins of the anterior pereonites.

Etymology
From Latin incavatus = hollow, concave.The name refers to the deeply concave sides of the posterior margins of the anterior pereonites.

Description
Maximum length: ♂, 4 mm.Body slightly convex, outline between pereon and pleon continuous, not able to conglobate (Figure 10A).Color pale after long preservation in alcohol.Dorsal cuticle covered with numerous short triangular scale-setae (Figure 10B).One line of noduli laterales per side close to posterior margin and far from lateral margins on pereonites 1-4 (Figure 10C,F).Some gland pores in small circles near anterior corners on all pereonites (Figure 10F).Cephalon with rounded median lobe, slightly depressed dorsally, and large quadrangular lateral lobes; large eyes with approximately 26 ommatidia (Figure 10D,E).Pereonites 1-3 with deeply concave posterior margin at sides (Figure 10A,F).Pleonites 3-5 with well-developed epimera (Figure 10A,G).Telson wider than long, with concave margins and narrowly rounded apex (Figure 10G).Antennula of three subequal articles, distal article with 7 or 8 subapical aesthetascs (Figure 10H).Antenna reaching back posterior margin of second pereonite; flagellum of two articles, with second article almost twice as long as first and covered with numerous thin and short setae (Figure 10I).Mandibles with molar penicil dichotomized; left mandible with 2 + 1 and right mandible with 1 + 3 free penicils (Figure 11A,B).Maxillula outer branch with 4 + 6 teeth, 4 of which subapically serrated; inner branch with long triangular apical point and two subequal penicils (Figure 11C).Maxilla inner lobe with apical part covered with fine and thick setae, distinctly wider than outer lobe (Figure 11D).Maxilliped palp with two strong setae on basal article; endite quadrangular, with triangular short seta and two acute lobes on distal margin (Figure 11E).Pleopods 1 and 2 exopods with Porcellio-type covered lungs (Figure 12C,D).Uropod with flattened exopod; endopod inserted distally, as long as exopod (Figure 11F).Pereopod 1 and, to lesser extent, pereopod 2, with brushes of setae on sternal margin of merus and carpus; ungual seta short, not reaching tip of outer claw, dactylar seta simple (Figure 12A).Pereopod 7 without distinct sexual modifications, ischium sternal margin straight (Figure 12B).Pleopod 1 exopod triangular with rounded posterior part bearing a few short setae apically; endopod with thickset apical part bearing truncate apex covered with thick tuft of long and thin setae (Figure 12C).Pleopod 2 exopod triangular with slightly concave outer margin with some setae; endopod distinctly longer than exopod (Figure 12D).Pleopods 3-5 exopods triangular (Figure 12E-G).

Ecology
Epigean species.No details on the collection method are available.

Remarks
This small Porcellio species is readily distinguishable from all the other species in the genus by the pereonites 1-3 having the posterior margins deeply concave at sides and by the male pleopod 1 endopod with truncate apex covered with a tuft of long and thin setae.

Etymology
From Segesta Tigulliorum, the Latin name of Sestri Levante where the specimens were collected.
Considering the systematic affinities of the new species and their distributions, different origins can be hypothesized.Buddelundiella zoiai sp.n. may have a West-Alpine origin, as most of the species in the genus, even if not all, are found on the south-western portion of the Alps.Sardoniscus marmoratus sp.n. shows a North-Apennine distribution, more similar to that of S. verhoeffi than of S. pygmaeus (Tyrrhenian distribution), indicating a putative origin in this geographic area.Cylisticus poggii sp.n. and Alloschizidium segestanum sp.n., both showing typical adaptations to endogean life, most likely have a Tyrrhenian origin.In fact, the majority of the species to which they are, respectively, most closely related have a Thyrrhenian distribution.As regards Porcellio incavatus sp.n., we have not been able to highlight any affinity with other species of the genus and therefore we cannot advance any hypothesis regarding its origins.Anyway, all these are just tentative hypotheses that need to be developed with deeper studies in the future.
As stated before, Liguria has never been thoroughly and adequately investigated as regards terrestrial isopods, despite its remarkable faunistic and biogeographic value.Therefore, the discovery and description of five species new to science belonging to five different families from this region should not be surprising.Indeed, we believe that the number of recorded species is still underestimated, especially among cave-dwelling and endogean isopods, and that future and more in-depth research may lead to further increase in oniscidean diversity in this region.

Figure 16 .
Figure 16.Distribution map of the five new species of Oniscidea from Liguria and surrounding regions.