Armadillidium Brandt 1831
Creators: name: Cifuentes, Julio
name: Robla, Jairo
name: Garcia, Lluc
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Armadillidiidae
Armadillidium

description: Key to the Iberian-Balearic species of the genus Armadillidium
Identification key of the Armadillidium species recorded in the Iberian Peninsula and the Balearic Islands. Mainly based on Schmölzer (1954; 1965); Vandel (1960; 1962); Cruz (1990; 1993); Cruz & Dalens (1990); Garcia (2003; 2020); Garcia & Cabanillas (2021); Cifuentes & Escarabajal (2022a, 2022b) and the present study. A. scabrum Dollfus, 1892, (only known from Seville) is excluded due to insufficient information in its original description (Dollfus, 1892). The distribution is indicated only for the endemic species.
1. Head of duplocarinate type, with scutellar and post-scutellar ridges.............................................. 2.
- Head of ‘ Armadillidium -type’ without scutellar ridge (linea frontalis)........................................... 13.
2. Conglobation ability of eusphaeric type (living animals can roll into a perfect ball). Integument smooth or weakly granulated................................................................................................... 3.
- Conglobation ability of pseudo/mesosphaeric type (living animals can roll into an ovoid or imperfect ball, respectively). Integument smooth, granulated or with spiniform tubercles.................................................... 6.
3. Telson triangular. Living animals with a vivid coloration, usually with yellowish muscle spots on a dark background. Integument smooth or slightly granulated............................................................................ 4.
- Telson trapezoidal. Very little or no pigmented body. Integument smooth, covered with bristle-like scale-setae. Male pereopod 7 with ventrally concave ischium and a protruded distal knob on the basis. Strictly littoral species... A. album Dollfus, 1887.
4. Male pleopod 1 endopod with distal third bent 90º outward. Exopod with notched tracheal field..... A. pictum Brandt, 1833.
- Male pleopod 1 endopod long and straight, only slightly bent apically............................................ 5.
5. Male pleopod 1 exopod without posterior lobe, twice as wide as long and with notched tracheal field. Galicia and Cantabric region ...................................................................... A. galiciense Schmölzer, 1955.
- Male pleopod 1 exopod with triangular posterior lobe, almost as long as wide, and with notched tracheal field. Asturias ......................................................................................... A. boalense sp. nov.
6. Integument smooth.................................................................................... 7.
- Integument with large or spiniform tubercles................................................................ 9.
7. Telson trapezoidal, with a wide posterior margin and straight lateral edges. Menorca (Balearic Islands).................................................................................................. A. strinatii Vandel, 1961.
- Telson triangular...................................................................................... 8.
8. Lateral edge of first the pereon-tergite, angulate. Male pereopod 7 without distinct sexual modification.Mallorca and surrounding islets (Balearic Islands)................................................................ A. cruzi Garcia, 2003.
- Lateral edge of the first pereon-tergite regularly curved. Male pereopods 6-7 with a marked distal knob on ischium; male pereopod 7 with ventrally concave ischium. Levantine Iberian region......................... A. espanyoli Cruz, 1992.
9. Telson trapezoidal.................................................................................... 10.
- Telson triangular..................................................................................... 12.
10. Telson with narrow posterior edge, rounded posterior angles and concave lateral edges; back covered with large conical tubercles; scale-setae with forked setae. Male pleopod 1 exopodite with short posterior lobe and notched tracheal field. Endemic from Murcia region ............................................... A. ibericum Cifuentes & Escarabajal Bernabé, 2022.
- Telson with broad posterior edge, obtuse posterior angles and straight lateral edges; scale-setae tricorn-type, without forked setae.............................................................................................. 11.
11. Cephalon with angled postscutellar ridge. Pleonites with a transverse row of strong granulations. Male pleopod 1 exopodite twice as wide as long, with barely prominent posterior lobe. Menorca (Balearic Islands)..... A. serrai Cruz & Dalens, 1990.
- Cephalon with regularly arched post-scutellar ridge. Pleonites without apparent granulations. Exopodite of the male pleopod 1 with distinct posterior lobe. Pre-Pyrenean Iberian region................................... A. nahumi Garcia, 2020.
12. Cephalon with strongly angulate post-scutellar ridge; scutellar ridge, complete. Back covered with hypertrophic spiniform tubercles. Telson broad and short, with broadly rounded apex. Mallorca (Balearic Islands).......... A. pretusi Cruz, 1992.
- Cephalon with regularly arched post-scutellar ridge; scutellar ridge incomplete. Body covered with spiny tubercles. Telson narrow, with straight lateral sides................................................ A. serratum Budde-Lund, 1885.
13. Telson trapezoidal.................................................................................... 14.
- Telson triangular..................................................................................... 15.
14. Conglobation ability of mesosphaeric type. Male pleopod 1 exopod with sinuous inner margin; endopod straight. Male pereopod 7 with a rounded distal bulge on ischium.............................................. A. sordidum Dollfus, 1887.
- Conglobation ability of eusphaeric type. Male pleopod 1 exopod with convex inner margin; endopod distally curved. Male pereopod 7 without distal bulge on ischium........................................... A. vulgare (Latreille, 1804).
15. Conglobation ability of mesosphaeric type. Back granulated. The posterior edge of the first pereon-tergite forms angles at the limit with the epimera............................................................ A. granulatum Brand, 1833.
- Back smooth or with very weak granulations.............................................................. 16.
16. Conglobation ability of pseudosphaeric type. Frontal shield almost twice as long as wide, very prominent above the vertex. The posterior margin of the first pereon-tergite forms angles at the limit with the epimera........ A. nasatum Budde-Lund, 1885.
- Conglobation ability of mesosphaeric type. Frontal shield slightly prominent and directed backwards above the vertex. Posterior margin of first pereon-tergite regularly sinuous............................................................. 17.
17. Male pleopod 1 exopod with very short posterior lobe................................ A. assimile Budde-Lund, 1885.
- Male pleopod 1 exopod with well-developed posterior lobe.............................. A. arcangelii Strouhal, 1929.
* Note that Armadillidium mateui Vandel is not currently included in the genus Armadillidium. This species has been transferred to Alloschizidium Verhoeff (see Cifuentes 2022). Thus, it was not included in the identification key.
description: Published as part of Cifuentes, Julio, Robla, Jairo & Garcia, Lluc, 2024, Description of Armadillidium boalense sp. nov. from northern Spain, with remarks and a key of the genus in the Iberian Peninsula and the Balearic Islands (Isopoda: Oniscidea: Armadillidiidae), pp. 83-99 in Zootaxa 5497 (1) on pages 96-97, DOI: 10.11646/zootaxa.5497.1.4, http://zenodo.org/record/13617904