Turcolana lepturoides, Prevorčnik, Simona, Konec, Marjeta & Sket, Boris, 2016

Prevorčnik, Simona, Konec, Marjeta & Sket, Boris, 2016, The first Turcolana Argano & Pesce, 1980 (Isopoda: Cirolanidae) from the Greek mainland, Zootaxa 4170 (1), pp. 125-136 : 130-135

Turcolana lepturoides sp. nov.

( Figs 2–19 )

Material examined. Holotype: ♂ (10 mm long, 3 mm wide), freshwater stream, the Melissotrypa Cave , 12 km W of village Kefalovryso (Elassona municipality), Larissa prefecture, Thessalía (Thessaly), Greece, 39°52'38" N, 22°02'58" E, 299 m a.s.l., 15. June 2014, coll. C. Fišer & S.M. Sarbu (PMSL-Isopoda-OBBFUL-MO214).

Paratypes: 2 ♂ (10.5 mm x 3 mm, 10.7 mm x 2.8 mm), same data as holotype (PMSL-Isopoda-OBBFUL- MO215 and -MO219), non-ovigerous ♀ (11.5 mm x 3.5 mm), same data as holotype (PMSL-Isopoda-OBBFUL- MO216).

Diagnosis. Body ca. 10 mm long and ca. 3 mm wide. Pleotelson semicircular posteriorly. Antenna length about 50% of BL, its flagellum with more than 20 articles. Propodial organs on male pereopods 2–3, their length about 80% of propodi. Pereopod 7 length 45% of BL. Pereopods 5–7 with more than 4 SRC along inferior margins of merus, carpus and propodus. Uropod styliform, about 2x as long as pleotelson. Uropod sympodite with 1 robust seta on posteromedial angle and 1 PL on medial margin, endopodite with 5 SRC on medial margin.

Description (holotype, male paratype in brackets). Habitus ( Figs 2–3 ): curved body lacking the ability of complete volvation. Body about 3.3x [3.8x] as long as greatest width. Head about 65% as wide as pereonite 1.

Coxae 4–7 clearly extending beyond posterior margins of respective pereonites, posterolateral angle produced. Pleonites 1–4 ( Fig. 3 ) of about the same width; posterolateral angles forming acute points; pleonite 5 approximately 85% as wide as pleonite 4 and as wide as pleotelson base, partly concealed by pleonite 4. Pleotelson ( Fig. 3 ) as long as greatest width; anterolateral margins oblique and converging, posterolateral margins strongly convex and forming evenly rounded pleotelson with posterior margin; dorsal surface and margins with short and fine SS.

Frons ( Fig. 4 ): clypeus with slightly protruding, clearly rounded median lobe, lateral angles distinctly deflected posteriad, frontal lamina with rounded apex and moderately protruding beyond median lobe of clypeus.

Antennula ( Fig. 5 ) short, about 16% [18.4%] of BL, hardly extending to pereonite 1; peduncle with 3 articles and rounded lobe on distodorsal margin of article 3, article 2 and article 3 1.3x and 2.5x as long as article 1, respectively; flagellum with 5 articles [4], article 1 1.3x as long as remaining flagellar articles; aesthetasc formula: 1, 2, 2, 1, 0 [1, 2, 3, 0]. Antenna ( Fig. 3 ) peduncle article 4 4x as long as wide, 2x as long as article 3; article 5 1.4x as long as article 4; flagellum with 27 [25] articles, extending to posterior margin of pereonite 4.

Mandible ( Figs 6 a, 6b) molar process anterior margin with row of 26–28 long and slender teeth; right mandible spine row with 10, left with 14 SR; palp article 2 with 9 SR on lateral margin, article 3 with 10 short SE on lateral margin and 3 longer SR on apex. Maxillula ( Fig. 7 ) lateral lobe with 8 CS, 2 PL and 1 SS. Maxilla ( Fig. 8 ) mesial lobe with 10 long SS, 2 PE and 1 PA; middle lobe 0.7x as long as lateral lobe. Maxilliped ( Figs 9 a, 9b) palp article 2 medial margin distally with 3 SS, distolateral angle with 1 SS; article 3 medial margin with 19 SS, lateral margin with 3 SS; article 4 distomedial angle with 8 SS, distolateral angle with 2 SS; article 5 distal margin with 7 SS, lateral margin with 2 SS; endite distal margin with 4 PA, medial margin with 5 PL and 2 coupling setae.

Pereopod 1 ( Fig. 17 ) long, 30% of BL; basis 2.5x as long as greatest width; merus inferior margin with 3 molariform CS and 3 [2] acute SRC (called spurs in Botosaneanu & Notenboom 1989). Pereopods 2–7 long, 35%, 37%, 39%, 41%, 43% and 45% of BL, respectively. Pereopod 2 ( Fig. 18 ) basis 4x as long as greatest width; ischium without SRC on inferior margin; merus, carpus and propodus with 6, 5 and 7 SRC on inferior margin, respectively. Pereopod 3 similar to pereopod 2. Pereopod 6 ( Fig. 19 ) basis 4x as long as greatest width; ischium with 3 SRC on inferior margin, 3 SRC on inferior distal angle and 3 SRC on superior distal angle; merus with 5 SRC on inferior margin, 3 SRC on inferior distal angle and 3 SRC on superior distal angle; carpus with 5 SRC on inferior margin, 3 SRC on inferior distal angle and 2 SRC on superior distal angle; propodus with 7 SRC on inferior margin, 1 SRC on inferior distal angle and 2 SS on superior distal angle. Pereopod 7 basis 4.2x as long as greatest width; ischium with 2 SRC on inferior margin, 2 SRC on inferior distal angle and 3 SRC on superior distal angle; merus with 2 SRC on inferior margin, 3 SRC on inferior distal angle and 3 SRC on superior distal angle; carpus with 5 SRC on inferior margin, 2 SRC on inferior distal angle and 3 SRC on superior distal angle; propodus with 9 SRC on inferior margin, 1 SRC on inferior distal angle and 1 SS on superior distal angle.

Pleopod 1 ( Fig. 10 ) sympodite rectangular; endopodite 1.3x as long and as wide as exopodite, lateral and medial margin straight, endopodite distally with 3 [5] PL and narrowly rounded; exopodite 2.4x as long as wide, distally with 2 PL and narrowly rounded. Pleopod 2 ( Fig. 11 ) endopodite 0.6x as long as exopodite; endopodite distally with 3 [4] PL, exopodite distally with 5 PL; appendix masculina 2x as long as endopodite. Pleopods 3–5 ( Figs 12–14 ) endopodites distally without PL, exopodites distally with 6 [3] PL, 5 [2] PL and 4 [1] PL, respectively; all PL delicate and extremely short.

Uropod ( Figs 3 and 16 ) sympodite 3x as long as greatest width, basal width 64% of apical width; medial margin strongly produced, posteromedial angle with 1 robust seta and 1 [2] PL; posterolateral angle with 2 [1] SRC and 1 long SS. Endopodite 1.1x as long as exopodite; endopodite basal width 4x apical width; medial margin with 3 PL proximally and 5 [6] SRC distally; endopodite lateral margin with long slender setae. Exopodite with parallel margins, narrowly rounded apically; margins without SRC, with numerous slender setae.

Female. Similar to male except: a ntennula aesthetasc formula: 1, 2, 2, 1. Pleopod 2 ( Fig. 15 ) endopodite 0.8x as long as exopodite; endopodite distally with 5 PL, exopodite distally with 3 PL; appendix masculine absent.

Distribution. Known only from the type locality.

Remarks. Turcolana lepturoides , sp. nov. is most similar to T. adaliae Botosaneanu & Notenboom, 1989 which has the longest appendages within other Turcolana species known so far. As no measurements are available in the description, we rely on the approximate estimates of lengths derived from the available drawing ( Botosaneanu & Notenboom 1989: p. 9, fig. 36). Uropods are shorter than pleotelson in T. adaliae (twice as long as pleotelson in the new species) and with broad and short endopodite (slender and long in the new species). Also, antenna of T. adaliae is 0.3x as long as BL (almost half of BL in the new species) and pereopod 6 is 0.36x as long as BL (0.43x in the new species).

Although the new species closely resembles its congeners in generic diagnostic characters, proportions of some appendages reveal some striking similarities with Botolana leptura ( Botosaneanu, Boutin & Henry, 1985) , belonging to the Typhlocirolana phyletic line ( Baratti et al. 2010). Also in this case we rely on the approximate estimates of lengths derived from the available drawing ( Botosaneanu et al. 1985: p. 188, fig. 1). The most conspicuous are long styliform uropods that protrude far beyond the pleotelson and most certainly restrict the ability of both species to roll into a ball. Despite similar proportions and shape, uropods of Botolana differ from the uropods in the new species in the chaetotaxy: there are at least 7 distinct long PL situated in a row on a sympodite medial margin (1 PL and 1 robust spine in the new species) and up to 3 SRC on endopodite medial margin (5–6 SRC in the new species). The additional similarities are slender and elongated pereopods and antennae. Pereopods 5–7 in Botolana leptura are about 0.4x, 0.42x and 0.47x as long as BL (0.41x, 0.43x, 0.45x in the new species) and the antennae are 0.47x as long as BL. Clearly, the two species are markedly convergent. The elongation of the mentioned appendages is well known progressive troglomorphy present in the inhabitants of spacious subterranean habitats in contrast to the interstitial ( Coineau 2000). Moreover, it turned out that both species have shorter antenullae: 0.13x as long as BL in B. leptura , 0.16x as long as BL in T. lepturoides sp. nov. while 0.18x as long as BL in T. adaliae . The same phenomenon was observed in troglobiotic Asellus aquaticus races ( Prevorčnik et al. 2004) and may in fact represent a lag behind the elongation of the body and antennae rather than the shortening per se. While it is evident that the habitat of T. lepturoides sp. nov. in the Greek cave is spacious, for B. leptura such habitat could be inferred not only from the shape of its body but also from its gastropod cohabitants ( Botosaneanu et al. 1985). Namely, they resemble more the Dinaric cave snail fauna than the interstitial snail fauna.

A comparatively large body size may be either an additional evolutionarily convergent trait or a symplesiomorphy.

Etymology. The species “ lepturoides ” name alludes to the long and slender uropods: λεπτός for “thin” (Ancient Greek) and oura is “tail” (Greek). As similar uropods are typical of Botolana leptura , a Greek suffix oides is added, meaning "resembles".

Molecular results. We managed to amplify both rRNA fragments only from the female paratype. The 12S nucleotide sequence ( Table 2 ) of T. lepturoides sp. nov. differs the most (K2P = 0.8) from the sequence obtained from the unidentified Turcolana from Turkey ( Baratti et al. 2010), which differs from all other analysed taxa (K2P = 0.71–0.75). Both gene fragments of the new Turcolana show closer similarity to the genera Typhocirolana and Botolana than to Saharolana seurati Monod, 1930 ( Table 2 ). The intrageneric genetic distances in Typholocirolana and Botolana are comparable to those obtained by Baratti et al. (2004), revealing higher intergeneric than intrageneric distances.

Our results suggest that the previous exclusion of the genus Turcolana from the monophyletic Sphaeromides group (sensu Botosaneanu et al. 1986) was probably due to the amplification of a pseudogene in the unidentified Turcolana from Turkey, as already suspected by the authors ( Baratti et al. 2010), or the specimen might have been misidentified. The Sphaeromides group now includes Turcolana with the peri-Mediterranean Sphaeromides Dollfus, 1897 , Botolana and Typhlocirolana , as well as 6 American genera. For better resolved phylogeny of the genus and its evolutionary relationships, however, sequences from other Turcolana species are needed.

Figures

FIGURE 2. Turcolana lepturoides sp. nov., holotype (♂, 10 mm): lateral view.

FIGURES 3 – 6. Turcolana lepturoides sp. nov., holotype (♂, 10 mm): 3, dorsal view. 4, frons. 5, right antennula and its distal part. 6 a, 6 b right and left mandible on external face, respectively.

FIGURES 7 – 15. Turcolana lepturoides sp. nov., holotype (♂, 10 mm): 7, left maxillula; 8, left maxilla 2; 9 a, 9 b, left and right maxilliped, respectively; all on external face. 10 – 14, right pleopods 1 – 5, respectively. 15, ♀ paratype (11.5 mm) right pleopod 2.

FIGURES 16 – 19. Turcolana lepturoides sp. nov., holotype (♂, 10 mm): 16, uropod. 17, pereopod 1. 18, pereopod 2 with extensive propodial organ. 19, pereopod 6.

Tables

TABLE 2. Pairwise genetic distances (K 2 P) between the analysed taxa for 12 S rDNA (below diagonal) and 16 S rDNA (above diagonal, grey shaded). Taxa abbreviations are given in Table 1. NA = not available.

T. lepturoides	T. sp. TUR	B. leptura LEP	Ty. sp. OUR	Ty. sp. SIC S. seurati SAHA
T. lepturoides *	NA	0.23	0.26	0.23 0.47
T. sp. TUR 0.80	*	NA	NA	NA NA
B. leptura LEP 0.25	0.75	*	0.11	0.17 0.43
Ty. sp. OUR 0.25	0.74	0.05	*	0.19 0.42
Ty. sp. SIC 0.27	0.71	0.15	0.16	* 0.47
S. seurati SAHA 0.70	0.8	0.67	0.65	0.63 *