Galliocookia gracilis, Golovatch, Sergei I., 2013

Golovatch, Sergei I., 2013, A reclassification of the millipede superfamily Trichopolydesmoidea, with descriptions of two new species from the Aegean region (Diplopoda, Polydesmida), ZooKeys 340, pp. 63-78 : 63-66

Galliocookia gracilis sp. n. Figs 1-6

Type material.

Holotype ♂ (NMNHS), Greece, Rhodes Island, village Archangelos, Cave Coumellos, 02.05.1987, leg. P. Beron.

Paratypes: 1 ♂, 1 ♀, 1 ♂ subadult (NMNHS), same locality, together with holotype.

Diagnosis.

Differs from the other species of Galliocookia Ribaut, 1955, all three from caves in southern France ( Mauriès 1983), by the somewhat larger size (8-9 mm versus maximum 6.7 mm in ♀ Galliocookia balazuci Mauriès, 1983, 7.5 mm in ♀ Galliocookia fagei Ribaut, 1955 or 7.7 mm in ♀ Galliocookia leclerci Mauriès, 1983), the presence of a distodorsal field of sensilla also in antennomere 5, of porosteles, the peculiarly upturned pre-apical teeth flanking the epiproct, as well as a trifid, not bifid, tip of the gonopod (with a small stump proximal to the solenomere).

Name.

To emphasize the highly gracile looks of this species.

Description.

Length of adults ca 8.0 (♂) or 9.0 mm (♀), width of midbody pro- and metazona 0.8 and 0.9 mm (♂, ♀), respectively. Coloration in alcohol uniformly pallid to, in front body quarter, light yellowish (Figs 1, 2).

Body with 19 (♂) or 20 (♀) segments, strongly moniliform. Tegument smooth, mainly slightly shining, texture very delicately alveolate. Head densely pilose throughout; ♂ epicranial modifications absent, frons being regularly convex in both sexes. Antennae long and slender, reaching behind segment 2 when stretched dorsally (♂, ♀); antennomeres 2-4 and 6 subequal in length, but 6th clearly the highest (height being measured from ventral to dorsal margin) (Figs 1, 3); antennomeres 5 and 6 each with a distinct, round, distodorsal, compact field of sensilla.

In width, head = segments 6-18(19)> 5> 4> 2 = 3> collum; body suddenly tapering on telson. Collum ellipsoid, acutangular caudolaterally, like most of following metaterga with three transverse, rather regular rows of setae until segment 15 or 16, following metaterga with 3-4 less regular rows in front of a 4th or 5th regular row at caudal margin. Tergal setae very short, simple, sharp, only about 1/5-1/6 the length of a metatergum, a little longer only on collum and penultimate segment, mostly 3+3 in each row, but gradually growing to about 4+4 or 5+5 per row towards telson. A very faint transverse sulcus in caudal 1/3 of metaterga in front of caudal row of setae. Dorsum invariably convex. Paraterga poorly developed, especially so in ♀, visible starting from collum, invariably slightly declivous, set rather high (mainly at about upper quarter or third of midbody height in ♂ and ♀, respectively), slightly, but regularly rounded laterally; lateral margin of postcollum paraterga clearly serrate, with 6-7 subequal, often setigerous indentations in front of a somewhat (♀) or much (♂) larger, isolated, sometimes nearly pointed tubercle, this in pore-bearing segments turning into a conspicuous porostele (Figs 1, 2). This caudal tubercle or porostele of paraterga drawn caudolaterad, but never extending behind rear tergal margin. Pore formula normal: 5, 7, 9, 10, 12, 13, 15-18(19), ozopores round, dorsal, quite evident due to their porosteles. Stricture between pro- and metazona wide, shallow and smooth. Limbus very finely microspiculate. Epiproct conical, rather long, but barely extending behind 2+2 conspicuous, pre-apical teeth, caudalmost of which unusually strong and upturned (Figs 1, 2). Hypoproct trapeziform.

Sterna clearly separated, unmodified. Legs rather long and slender, without modified setae, ca 1.3-1.4 (♂) or 1.1-1.2 (♀) times as long as midbody height, femora and tarsi longest, claw short (Fig. 4). Epigynal ridge very low, inconspicuous.

Gonopod aperture transversely oblong-oval, taking up most of ventral part of metazonite 7. Gonopods (Figs 5, 6) with small, subglobose, evidently exposed, medially fused coxae, each carrying only 1 long seta distolaterally and a long, curved cannula distomesally; a scaly texture on lateral face absent. Telopodite suberect, slender and long, up to about its half being taken up by an elongate, setose prefemoral part; acropodite slightly helicoid, its apical lobe subacuminate, with a pre-apical, lobe-shaped, subtriangular solenomere (sl) and a short, papillate, rounded stump a little proximally. Both prefemoral part and acropodite strictly coaxial, in situ directed forward and parallel to each other. No traces of accessory seminal chamber or hairy pulvillus.

Remarks.

Among the Euro-Mediterranean genera of Trichopolydesmoidea , only some show a deeply bipartite and strongly curved gonopod telopodite, the prefemoral part of which is quite elongate, but lies more or less transversely to strongly angular, largely (sub)parallel telopodites and extends across the nearly entire ventral width of segment 7. Such are Trichopolydesmus Verhoeff, 1898 (together with Banatodesmus Tabacaru, 1980), Bacillidesmus Attems, 1898, Napocodesmus Ceuca, 1974 and Caucasodesmus Golovatch, 1985. In contrast, the gonotelopodites in Verhoeffodesmus Strasser, 1959, Cottodesmus Verhoeff, 1936 and Occitanocookia Mauriès, 1980 have increasingly shortened prefemoral parts, being enlarged and laterally flattened distad, unipartite and mostly less strongly curved, in Cottodesmus and Occitanocookia also devoid of a solenomere, but sometimes supplied instead with what can be seen as a primordial accessory seminal chamber. In Trichopolydesmus , Heterocookia Silvestri, 1898, Ingurtidorgius Strasser, 1974 and, especially, Mastigonodesmus Silvestri, 1898, the solenomere is flagelliform, branching off near the base of the femorite. In all these genera, the gonotelopodites are strongly exposed, not sunken inside an obvious central coxal cavity (= gonocoel). A modest gonocoel seems to only be observed in Ingurtidorgius and Haplocookia Brölemann, 1915. This latter genus does resemble Galliocookia , but its gonopod telopodite is clearly curved, there is a small gonocoel and both sexes have 20 body segments (see also review by Mauriès 1983).

The new species definitely belongs to Galliocookia , sharing with the other three congeners (see Diagnosis above) a small coxa and a slender, simple and suberect telopodite, the latter showing an extended prefemoral part strictly coaxial with the acropodite. Moreover, the solenomere is likewise modest, lobe-shaped and located distally. Even the presence of 19 or 20 body segments in the male and female, respectively, as well as of a normal ozopore formula, setose metaterga and laterally serrate/indentate paraterga coincide.

Biogeographically, the discovery of a Galliocookia in the Aegean region, so far away from France, is remarkable, emphasizing a pan-Mediterranean distribution pattern of this currently purely cavernicolous, likely troglobitic genus.