Porcellionides glaber ( Koch, 1856 )

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 : 15-19

Porcellionides glaber ( Koch, 1856)

Figs 2D, L , 3D , 4M–P , 10–11, Table 1

Porcellio glaber Koch, 1856: 420 .

Metoponorthus sexfasciatus glaber Vandel, 1961: 257 .

Metoponorthus glaber – Vandel 1953: 48, fig 1.

Material examined

SPAIN – Cádiz • 2 ♂♂, 1 ♀; Algeciras ; 13 Jan. 1907; Arias leg.; cited as P. sexfasciatus lusitanus by Cifuentes (2021a); MNCN 20.04/12308 • 2 ♂♂, 3 ♀♀; Arcos-Bornos ; 25 Nov. 2004; M. García Paris leg.; cited as P. sexfasciatus lusitanus by Cifuentes (2021a); MNCN 20.04/6120 • 1 ♀; Puerto Real, Las Canteras ; 24 Nov. 2004; M. García Paris leg.; cited as P. sexfasciatus lusitanus by Cifuentes (2021a); MNCN 20.04/12315 • 6 ♂♂, 19 ♀♀; Tarifa ; 22 Feb. 1912; cited as P. sexfasciatus lusitanus by Cifuentes (2021a); MNCN 20.04/10003 • 4 ♂♂; Sierra de Cádiz ; J. García leg., JC527 . – Gibraltar • 1 ♂, 15 ♀♀; Gibraltar ; 19 Feb. 1912, MNCN 20.04/12385 . – Huelva • 1 ♂; Alájar ; 23 Apr. 1980; E. Ortiz de Vega leg.; cited as P. sexfasciatus lusitanus by Cifuentes (2021a); MNCN 20.04/9482 • 3 ♂♂, 10 ♀♀; Cala ; Feb. 1915; C. Bolívar and J. Fernández Nonidez leg.; cited as P. sexfasciatus lusitanus by Cifuentes (2021a); MNCN 20.04/8058 • 2 ♂♂, 13 ♀♀; Doñana ; 14 May 1966; E. Ortiz de Vega leg.; cited as P. sexfasciatus lusitanus by Cifuentes (2021a); MNCN 20.04/7886 • 6 ♂♂, 11 ♀♀; Doñana ; 23 Apr. 1980; E. Ortiz de Vega leg.; cited as P. sexfasciatus lusitanus by Cifuentes (2021a); MNCN 20.04/9919 . – Islas Baleares • 5 ♂♂; Menorca, Ciutadella, Platja dels Algaiarens - La Vall; 23 Mar. 1989; A. Cruz leg.; A. Cruz coll., CRBA-86565 • 7 ♂♂; Maó, Es Grau ; 21 Mar. 1989; A. Cruz leg.; A. Cruz coll., CRBA-86562 . – Málaga • 4 ♂♂, 16 ♀♀; Benaoján ; 6 May 1952; E. Ortiz de Vega leg.; cited as P. sexfasciatus lusitanus by Cifuentes (2021a); MNCN 20.04/11490 • 2 ♂♂; Serranía de Ronda, Puerto del Pozuelo, Sierra Nieves ; 16 Apr. 1987; O. Escolà leg.; cited as P. sexfasciatus lusitanus by Cifuentes (2021a); A. Cruz coll.; CRBA-86540 .

Description

COLORATION. Color varies among different specimens, ranging from dark brown to reddish, with well-defined muscle insertions ( Fig. 10A–B ). First two antenna segments, pleonite epimera, and tips of neopleurons display lighter color, sometimes whitish or intensely red.

INTEGUMENTARY CHARACTERS. Integument smooth and shiny ( Fig. 10A–B ) or with some very thin granulations ( Table 1 ). Glandular fields at lateral edge of pereonites epimera with numerous pores. Noduli laterales located in small depigmented area, slightly separated from edge, with b/c and d/c coordinates as in Figs 2D , 10C . Scale-setae triangular, very small, but with wide tip ( Fig. 3D ).

SOMATIC CHARACTERS. Body bulged ( Fig. 10A–B ). Cephalon with softly arched frontal line, lateral lobes reduced to protrusions, and supra-antennal line prominently marked. Pereon with nearly straight posterior edge for first three pereonites and all pereonites present highly noticeable transverse ridge curving over noduli laterales. Pleon retracted in relation to pereon. Telson with very small base and broadly triangular tip with pointed end.

APPENDAGES. Antennae extend beyond posterior edge of pereonite III, first segment of flagellum longer than second. Uropods with protopod slightly longer than telson tip, featuring transversely oriented posterior edge. Endopods much longer than telson. Exopods elongated and conical in both sexes. Pereopods without sexual differentiation.

MALE SEXUAL CHARACTERS. Exopod of pleopod I with inner lobe ending in curved tip ( Figs 4M , 10D). Exopod of pleopod II triangular with long posterior inner tip ( Figs 4N , 10E). In females ( Fig. 4O–P ), only first exhibits small tip, and second similar to those of other studied species.

Remarks

This species was initially described as Porcellio glaber by Koch (1856). It was subsequently placed within the genus Metoponorthus Budde-Lund, 1879 as Metoponorthus glaber by Budde-Lund (1885), and treated similarly by Vandel (1946). Later, Vandel (1953) considered the possibility that it might be a species with uncertain status, or alternatively, a form or subspecies of P. sexfasciatus . In later works, Vandel referred to it as a subspecies of Porcellionides sexfasciatus ( Budde-Lund, 1885) in his studies from Menorca ( Vandel 1961) and France ( Vandel 1962). Currently, P. glaber is commonly regarded as nomen dubium ( Boyko et al. 2023).

The original description of this species by Koch (1856), generally follows the common practices of its time, presenting few truly distinguishing characters for the species. Some important details from its description include: species exhibits a shiny, moderately convex and elongated body; antennae are long and slender, with the first segment of the antennal flagellum slightly longer than the second; lateral lobes are absent from the cephalon, replaced by a narrow crest; cephalon is grey, and the first antennal segments are reddish-brown; and the dorsal surface of the tergites exhibits a transverse ridge. Lastly, Koch (1856) adds that it is not uncommon in Málaga. Budde-Lund (1885) provides several additional details, as follows: species possesses a convex, smooth, shiny appearance, lacking middle and lateral lobes; telson is triangular with slightly curved sides, and their coloration varies from black to brown. Additionally, he also mentions that this species is present in Málaga. While these descriptions suggest that this species shares similar characters with other species within the Porcellionides genus, including P. sexfasciatus , none of the previous authors mention the presence of more or less pronounced longitudinal lines. Such lines are highlighted by Budde-Lund (1885) for P. sexfasciatus , and they are distinctive enough to have earned the species its name.

In his work on isopods of Portugal, Vandel (1946), describes three new subspecies for P. sexfasciatus : P. sexfasciatus bernardi ( Vandel, 1946) , P. sexfasciatus lusitanus ( Vandel, 1946) , and P. sexfasciatus mamorensis ( Vandel, 1946) . He justifies their inclusion within the same specific entity, P. sexfasciatus , based on the presence of transverse ridges on the tergites, scale-setae, scale structures, and glandular fields ( Vandel 1946: 267). However, these characteristics are also found in other species of the genus, although the scale-setae are not identical across all of them ( Fig. 3 ). Regarding P. sexfasciatus mamorensis , important characters highlighted by Vandel (1946: 263 and onwards) include the presence of granulations that are particularly challenging to discern. In males, the carpus and merus of the pereopod 1 exhibit a dense brush of setae, as well as a sharply curving posterior inner tip on the exopod of the pleopod I ( Vandel 1946: 266, fig. 80e), which is set apart from the base by a small projection. Concerning its geographical range, this subspecies appears to be localized in a small region in Morocco.

We examined several specimens that align with the descriptions provided by Koch (1856) and Budde-Lund (1885) for their Porcellio glaber . These specimens also correspond to the descriptions provided by Vandel (1946) for P. sexfasciatus lusitanus and for P. s. mamorensis. Among these specimens, some originate from Benaojan (Málaga), located 37 km in a straight line from Casarabonela, which is the type locality according to Koch, along with others from various locations in Andalusia. To aid the identification of P. glaber , we provide a brief species description above.

Porcellionides glaber can be distinguished from P. sexfasciatus by its highly convex body, smooth integument, the presence of transverse ridges on all tergites, the noduli laterales position, the broadtipped scale-setae and in males, by the exopod of the pleopod I with a very fine and curved posterior inner tip. In contrast, the body of P. sexfasciatus body is elongated, with thin granulations on the integument, lacking transverse ridges on the first pereonite, scale-setae with a sharp tip, and, in males, the exopod of the pleopod I exhibits a very wide and elongated posterior inner tip. Based on the aforementioned characters, we validate the species described by Koch as P. glaber ( Koch, 1856) . Unfortunately, we were unable to analyse specimens of P. s. mamorensis from North Africa, but this subspecies differs from P. glaber in the carpus and merus of the pereopod 1, which possess a dense brush of setae, in contrast with their absence in P. glaber . Furthermore, as will be explained in detail below, some of the specimens identified by Vandel (1946) as P. s. lusitanus , based on the morphology of the male pleopod I and the absence of sexual differentiation in the pereopods, are likely to be P. glaber .

Distribution

Found in the southern part of Spain and in the northern region of Africa ( Morocco), based on specimens identified by Vandel (1946) as P. s. lusitanus from Mamora. There is a record from Mont Estoril, Lisbon, Portugal, by Jackson (1926). However, this citation is highly likely to be an identification error, possibly resulting from confusion with other species due to its coloration. Porcellionides glaber is typically found in considerably drier environments compared to those found in Mont Estoril, as indicated by its established distribution range ( Fig. 11 ).

In Spain, it has been reported from the provinces of Cádiz: Vejer de la Frontera and Villaluenga del Rosario by Cruz (1991), Algeciras, Arcos-Bornos, Puerto Real, Tarifa and Vejer de la Frontera by Cifuentes (2021a), in both references identified as P. sexfasciatus lusitanus ; Huelva: Alájar, Cala and Doñana by Cifuentes (2021a) identified as P. sexfasciatus lusitanus ; Islas Baleares: Menorca, as P. sexfasciatus glaber by Vandel (1961) and Cruz (1989); Málaga: Carratraca, Casarobonela ( Budde-Lund 1885), Málaga ( Koch 1856), Puerto del Pozuelo by Cruz (1991), Benaoján and Puerto del Pozuelo by Cifuentes (2021a), with the latter two references identifying it as P. sexfasciatus lusitanus .

It is recorded for the first time in the Spanish provinces of Cádiz and Huelva as well as for Gibraltar ( Fig. 11 ).

Figures

Fig. 2. Relation between noduli laterales coordinates (following Vandel 1960) d/c (y-axis) and b/c (x-axis) multiplied by 100 for all studied species. A. Porcellionides cingendus (Kinahan, 1857). B. Porcellionides elegans(Pollo Zorita, 1982). C. Porcellionides fuscomarmoratus(Budde-Lund, 1885). D. Porcellionides glaber (Koch, 1856). E. Porcellionides hispanus (Vandel, 1953). F. Porcellionides lucasioides (Vandel, 1953). G. Porcellionides lusitanus (Vandel, 1946). H. Porcellionides molleri (Verhoeff, 1901). I. Porcellionides pruinosus (Brandt, 1833). J. Porcellionides sexfasciatus (BuddeLund, 1885). K. Porcellionides ibericus sp. nov. L. P. sexfasciatus and its previously considered subspecies: P. glaber (g), P. hispanus (h), P. lucasioides (l), P. lusitanus (lu), P. molleri (m) and P. sexfasciatus (s).

Fig. 3. Scale-setae. A. Porcellionides cingendus (Kinahan, 1857), ♂ (JC104). B. Porcellionides elegans (Pollo Zorita, 1982), ♂ (MNCN 20.04/7306). C. Porcellionides fuscomarmoratus (BuddeLund, 1885), ♀ (MNCN 20.04/8129). D. Porcellionides glaber (Koch, 1856), ♀ (MNCN 20.04/11490). E. Porcellionides hispanus (Vandel, 1953), ♂ (MNCN 20.04/7163). F. Porcellionides lucasioides (Vandel, 1953), ♂ (JC352). G. Porcellionides lusitanus (Vandel, 1946), ♂ (LPS661). H. Porcellionides molleri (Verhoeff, 1901), ♀ (LPS135). I. Porcellionides pruinosus (Brandt, 1833), ♀ (JC318). J. Porcellionides sexfasciatus (Budde-Lund, 1885), ♂ (LPS455a). Scale bar = 0.01 mm.

Fig. 4. Pleopods. A–D. Porcellionides cingendus (Kinahan, 1857). A–B. ♂ (LPS215). A. Exopod I. B. Exopod II. C–D. ♀ (MNCN 20.04/11972). C. Exopod I. D. Exopod II. E–H. Porcellionides elegans (Pollo Zorita, 1982). E–F. ♂ (JC490). E. Exopod I. F.Exopod II. G–H. ♀ (MNCN 20.04/9590). G. Exopod I. H. Exopod II. I–L. Porcellionides fuscomarmoratus (Budde-Lund, 1885). I–J. ♂ (UGMSS-2). I. Exopod I. J. Exopod II. K–L. ♀ (MNCN 20.04/8129. K. Exopod I. L. Exopod II. M–P. Porcellionides glaber (Koch, 1856). M–L. ♂ (MNCN 20.04/7886). M. Exopod I. N. Exopod II. O. ♀ (MNCN 20.04/11490), exopod I. P. ♀ (MNCN 20.04/11490), exopod II. Q–T. Porcellionides hispanus (Vandel, 1953). Q–R. ♂ (MNCN 20.04/7163). Q. Exopod I. R. Exopod II. S–T. ♀ (JC380). S. Exopod I. T. ♀ (JC380), exopod II. Scale bars = 0.1 mm.

Fig. 10. Porcellionides glaber (Koch, 1856). A–B. ♂ (JC527), habitus. C. Noduli laterales coordinates. D–E. ♂ (MNCN 20.04/7886). D. Exopod I. E. Exopod II. Scale bars: A–B = 1 mm; D–E = 0.1 mm.

Fig. 11. Localization of the Ibero-Balearic region in Europe and the distribution of Porcellionides glaber (Koch, 1856).