Tiroloscia exigua ( Budde-Lund, 1885 )

Gardini, Pietro, Sabatelli, Simone, Taiti, Stefano & Audisio, Paolo, 2025, Hidden species’ diversitv and phvlogenetic relationships within the terrestrial isopod genus Tiroloscia (Crustacea: Isopoda: Oniscidea), Zoological Journal of the Linnean Society 203 (1), pp. 1-17 : 9-10

Tiroloscia exigua ( Budde-Lund, 1885)

( Figs 2A , 4A–L )

Philoscia exigua Budde-Lund 1885: 209 . Dollfus 1897: 94, pl. II, fig. 8; 1899: 207. Carl 1908: 160, pl. III figs 72–76, pl. VI fig. 158.

Philoscia (Paraphiloscia) exigua ; Verhoeff 1908a: 524. Dahl 1916: 36.

? Philoscia (Tiroloscia) squamuligera briani Verhoeff 1931a: 545 , fig. 40; 1936: 107.

Philoscia (Tiroloscia) squamuligera tendana Verhoeff 1931a: 545 , figs 35, 36; 1932: 379, 380.

Philoscia (Tiroloscia) exigua ; Arcangeli 1932: 13. Vandel 1946: 35. Legrand 1950: 47.

? Tiroloscia squamuligera bargensis Verhoeff 1936: 106 , fig. 29.

Tiroloscia exigua ; Vandel 1962: 524–528, figs 259, 260. Séchet and Noël 2015: 68.

Type locality: Artemare , Ain department, France ( Fig. 1 , site 13) .

Material examined: Lineage L1. Italy—Piedmont: 4♂♂, Sampeyre ( CN), loc. Dragoniere (site 6), 1100 m a.s.l., 03.I.2020, P. Gardini leg. ; 2♂♂, Sampeyre ( CN), loc. Rore (site 7), beech forest, 1300 m a.s.l., G. and P. Gardini and S. Zoia leg. Lineage L 2 . Italy—Piedmont: 1♂, Chiusa di Pesio ( CN), Pian delle Gorre (site 1), 1050 m a.s.l., 11.VIII.2020, P. Gardini leg. Lineage L 3. Italy—Piedmont: 1♂, Sampeyre ( CN), Meire Biun (site 4), 1530 m a.s.l., 03.VIII.2020, G. and P. Gardini leg. ; 2♂♂, Sampeyre ( CN), Pian Ciattiva (site 5), 1800 m a.s.l., 07.VIII.2020, P. Gardini leg. ; 1♂, Sampeyre ( CN), loc. Dragoniere (site 6), 1100 m a.s.l., 03.I.2020, P. Gardini leg. Lineage L 4. Italy—Piedmont: 2♂♂, Limone Piemonte ( CN), S. Maurizio (site 2), 1020 m a.s.l., 05.VII.2021, G.B. Delmastro leg. ; 1♂, Trinità di Entracque ( CN) (site 3), beech forest, 1300 m a.s.l., 17.VIII.2020, P. Gardini leg. ; 2♂♂, Barge ( CN), loc. Lungaserra (site 8), chestnut forest, 630 m a.s.l., 01. VI.2021, P. Gardini leg. ; 3♂♂, Revello ( CN), Staffarda (site 9), 265 m a.s.l., 27. V.2021, G.B. Delmastro leg. France — Savoie : 7♂♂, Apremont , Col du Granier (site 12). Ain : 4♂♂, Chanay , Col de Richemond (site 14), beech forest, 1140 m a.s.l., 19.IX.2020, G. and P. Gardini and C. Giusto leg. ; 3♂♂, Valserhône (site 15), 19.IX.2020, G. and P. Gardini and C. Giusto leg.

Previous records: France —Ain: Artemare ( Budde-Lund 1885); Mont Rond ( Carl 1908); Labalme, near Poncin; Virieu-le-Grand ( Vandel 1962). Alpes-Maritimes: Saint-Dalmas-de-Tende ( Verhoeff 1931a); Caussols; Fontan ( Vandel 1962). Drôme: Die ( Vandel 1962). Haute-Savoie: Chamonix ( Dollfus 1897, 1899, Legrand 1950); Saint-Cergues ( Carl 1908); Le Chatelard; Les Bossons; La Giettaz; La Clusaz; Col de Leschaux; Flumet; Mégevette ( Legrand 1950). Hautes-Alpes: Gap; Château-Queyras. Isère: Dent-de-Crolles. Jura: Villards-d’Héria ( Dollfus 1897, 1899); Viry; Choux; Vulvoz; Molinges ( Vandel 1946). Rhône: Saint-André-la-Côte ( Vandel 1962). Italy—Piedmont: Limone Piemonte; Ormea; Villanova Mondovì ( Verhoeff 1931a). Gran Paradiso National Park: Gran Piano di Noasca, Alpe Bruna, Vallone Noaschetta ( Arcangeli 1932). Ala di Stura; Barge; Ceres;?Cossila; Crissolo; Pinerolo ( Verhoeff 1936). Switzerland —Bois de Saint-Livres, near Bière; Bois-de-Bay, near Vernier; Prangins, near Nyon; Veyrier ( Carl 1908); Salvan ( Vandel 1962).

Description

Male pleopod 1

Lineage L1 ( Fig. 4A–C ): Exopod cordiform, with well-developed but rather narrow posterior tip, rounded apex with fine setae; inner margin straight in distal half, outer margin concave with three setae in proximal part; width/length ratio 1.25. Endopod with sinuous distal part provided with row of short, strong setae; apical part distinctly bilobed with two triangular lobes protruding distally, large and broadly rounded inner lobe; distal part strongly bent outwards when observed on whole animal.

Lineage L2 ( Fig. 4D–F ): Exopod cordiform, with well-developed posterior tip, rounded apex; inner margin slightly concave in distal half, outer margin concave with three setae in proximal part; width/length ratio 1.27. Endopod with parallel-sided distal part, with slightly sinusoidal row of short setae; apical part triangular, bilobed, with small, rounded subapical lobe on outer margin.

Lineage L3 ( Fig. 4G–I ): Exopod cordiform, with broadly rounded posterior tip; inner margin convex, provided with fine setae in distal half, outer margin straight with three setae in proximal part; width/length ratio 1.25. Endopod with triangular distal part, with slightly sinusoidal row of short setae; apical part with two lobes, outer one much shorter than inner one, apex rounded, almost straight when observed on whole animal.

Lineage L4 ( Fig. 4 J-L): Exopod cordiform, with well-developed, broadly rounded posterior tip; inner margin convex, outer margin slightly concave with three setae in proximal part; width/ length ratio 1.20. Endopod with sinuous distal part provided with row of short, strong setae; apical part bilobed with large, broadly rounded inner lobe; distal part strongly bent outwards when observed on whole animal.

Remarks

Specimens belonging to the four lineages show a certain degree of morphological differentiation and can be distinguished based on the fine structure of the male pleopod 1 endopod. Lineage L1 is readily distinguished from the others by the distinctly bilobed apical part of the endopod, with two clearly visible triangular lobes, with the one on the outer face highly developed. It is similar to L 4 in having the distal part of the endopod distinctly sinuous, but the latter is readily distinguished by the much less developed apical lobes. Lineage L2 is similar to L 1 in having a rounded subapical lobe on the outer margin of the male pleopod 1 endopod, although much less developed, but is easily distinguished from both L1 and L4 by having the distal part of the endopod almost straight with parallel sides and no broadly rounded inner lobe. Lineage L3 is readily distinguished from L1 and L 4 in having the male pleopod 1 endopod almost straight, with two less developed apical lobes, of which the outer one much shorter than the inner one. It differs from L 2 in having a rounded apical part rather than a triangular one, and in the absence of a subapical lobe.

Figures

Figure 1. Map showing sampling sites. The numbers refer to the sites listed in the Supporting Information, Tables S1 and S2. The dashed line depicts the documented range of Tiroloscia exigua based on examined specimens and literature records.The colours refer to lineages identified in phylogenetic analyses (see Fig. 2).

Figure 2. Phylogenetic tree from Bayesian inference (BI) analysis constructed using COI, 16S, and 28S markers.Posterior probabilities>0.85 (in black) and bootstrap values above 70 (in red) are shown above and below the nodes, respectively. Colours correspond to identified lineages within Tiroloscia exigua. Tiroloscia squamuligera is already recognized as a separate species based on our results and considerations. A summary of molecular species’ delimitation results and morphological investigation is depicted on the right. Above left is a specimen of T. exigua (A) from Arvière-en-Valromey (Ain), France and of T. squamuligera (B) from Razzes (BZ), Italy.

Figure 4. Morphological differences in the shape of the male pleopod 1 endopod between the five lineages. A–C, lineage L1: A, pleopod 1; B, tip of pleopod 1 endopod, outer face; C tip of pleopod 1 endopod, inner face.D–F, lineage L2: D, pleopod 1; E, tip of pleopod 1 endopod, outer face; F, tip of pleopod 1 endopod, inner face.G–I, lineage L3: G, pleopod 1; H, tip of pleopod 1 endopod, outer face; I, tip of pleopod 1 endopod, inner face. J–L, lineage L4: J, pleopod 1; K, tip of pleopod 1 endopod, outer face; L, tip of pleopod 1 endopod, inner face. M–O, lineage L5: M, pleopod 1; N, tip of pleopod 1 endopod, outer face; O, tip of pleopod 1 endopod, inner face.