Chirocephalus tauricus Pesta, 1921

Cottarelli, Vezio, Aygen, Cem & Mura, Graziella, 2010, Fairy shrimps from Asiatic Turkey: Redescription of C hirocephalus tauricus Pesta, 1921 and descriptions of C hirocephalus algidus sp. nov. and C hirocephalus brteki sp. nov. (Crustacea, Branchiopoda, Anostraca), Zootaxa 2528, pp. 29-52 : 30-36

Chirocephalus tauricus Pesta, 1921

( Figs.1–4 ; fig.12)

Material examined: two topotypic specimens, 1 male and 1 female (collection of the Museum of Natural History of Vienna) Kotschy coll. 1853; the male was dissected and mounted in polyvinyl-lactophenol on 15 slides marked C. tauricus male and numbered from 1 to 15. The female is preserved in 80% ethanol and glycerine in the collection of G. Mura, Dept. of Animal and Human Biology, University of Rome “La Sapienza”.

Description. Male. Length of preserved specimen, 8.2 mm. Thoracic and abdominal somites unadorned. First antennae thin, bearing at the apex three long distal setae and a few aesthetascs (impossible to determine their real number due to shrinkage of the only specimen available).

Second antennae ( Figs. 1 C–D and 12 a–b) long and thin; proximal antennomere shorter than the distal, cylindrical and slightly bent, relatively squat, bearing a conical apophysis rounded at its apex covered with several very small denticles. The apophysis is as long as one-third of the proximal antennomere. Distal antennomere long and thin, curving nearly at a right angle in its proximal part (at about one-third of its length), then straight and ending in a flattened and expanded apex. The medial margin of the article bears proximally a characteristic apophysis, thin and pointed, with a curved apex directed backwards provided with a few sharp tubercles; a few similar tubercles occur near the origin of the apophysis. Lower lamella ( Fig. 1 A) of the antennal process without dorsal carina, bilobed. The outer lobe is rounded with marginal finger-like outgrowths; the inner lobe is approximately triangular, narrowing and sharpening at the apex with marginal finger-like apophyses and tubercles. Some other tubercles are inserted on the surface. Upper lamella ( Fig. 1 B) relatively short, slightly longer than half of the lower lamella, provided with numerous lateral finger-like expansions, thin and approximately cylindrical, gradually tapering towards the tip.

Labrum ( Fig. 2 H): distal lobe particularly short in ventral view, not exceeding the distal margin of the labrum.

Mandibles ( Figs. 2 B–E and 12 d–f) asymmetrical: near its posterior tip, molar surface of right mandible provided with three sharp spines nearly of the same length; molar surface of left mandible bears a row of eight strong teeth on the lateral outer margin.

First pair of maxillae resembles that previously observed in Chirocephalus cupreus Cottarelli et al., 2007 and also in the two new species described herein. In C. tauricus , these appendages are adorned as shown in Fig. 2 A; there is also a posterior ventral modified spine ( Fig. 2 A,F), ending in a particularly thin and pointed apex. Second pair of maxillae ( Fig. 2 G) bearing three strong pennate setae, approximately of the same length.

Thoracic appendages: notopods of the first, sixth and eleventh pair ( Figs. 3 A–B, D). Also in this species, some of the thoracopods are characterized by the margins of the endites and the endopodite bearing sharp projections (a total of ten in C. tauricus ), arising close to the origin of the setae (as in the sixth pair illustrated in Figs. 3 F–G).

Genital segments ( Figs. 3 C, 4B, 12c): gonopods (sensu Rogers et al., 2007) not differing from the morphology known for the species of the group: distal eversible portion of the gonopods ( Fig. 3 E) ending in a slightly curved apex bearing two-three tiny tubercles. Cercopods ( Fig. 4 K) somewhat shorter than the three last somites: adorned with long setae each bearing a setose fringe.

Female. Length measured as in the male: 8.8 mm.

First antennae like those in the male; also for the female, it was impossible to determine the number and shape of the apical aesthetascs.

Second antennae ( Fig. 4 H) somewhat longer than the stalked eye, proportionally narrow and long, with parallel margins tapering towards the thin, pointed and slightly bent apex.

Sixth pair thoracopods do not exhibit the sharp projections seen in the male.

Abdominal somites ( Fig. 4 C) of the second to sixth pairs are adorned ventrally on the latero-posterior margin by verruciform outgrowths differing in shape and size ( Figs. 4 D–I; The seventh somite ( Fig. 4 J) also has a slightly raised area with two sensilli in its centre, which was not described by Pesta. The brood pouch ( Fig. 4 A) is short and swollen.

Cercopods of the only female observed appear shorter than in the male (although it is not known if this difference is true sexual dimorphism or is due to individual variation).

Affinities. The species is known only from the Taurus Mountains. Details of the locus typicus and habitat are unavailable ( Pesta, 1921; Brtek, 1966), as no description was provided by the collector.

Pesta ascribed Chirocephalus tauricus to the subgenus Chirocephalellus Daday, created by this author to include all of the Chirocephalus taxa in which there is no robust finger-like latero-basal outgrowth of the upper lamella. Pesta also stated that C. tauricus was particularly close to C. appendicularis ( Vàvra, 1905) . Ruffo and Vesentini (1957) described an interesting high altitude endemism from Italy, C. marchesonii , and considered it the westernmost representative of a taxon, Chirocephalellus, with an eastern distribution. In 1966, Brtek questioned the validity of the subgenus, which was also rejected by other authors ( Cottarelli, 1971; Cottarelli & Mura, 1983). In a series of further contributions ( Brtek, 1968, 1971, 1984, 1995; Brtek & Thiéry, 1995), the taxa belonging to the genus Chirocephalus were distributed in different species groups, and several Chirocephalellus, i.e. C. tauricus , were included in Brtek’s “ diaphanus ” group (Brtek, 1995). In the “ diaphanus ” group, the absence of a latero-basal finger-like outgrowth of the upper lamella is shared by C. appendicularis , C. marchesonii , C. skorikowi Daday, 1913 , C. weisigi Simon, 1933 , C. neumanni Hartland- Rowe, 1967, C. ponticus Beladjal & Mertens, 1997 , and C. algidus sp. nov.

As previously noted by Pesta, 1921, C. tauricus is small-sized, and from this point of view, C. marchesonii is the closest species. In C. tauricus males, the distal article of the antenna is longer than the basal one, a character shared by C. marchesonii , C. weisigi , C. algidus sp. nov., C. skorikowi and C. neumanni . The shape and morphology of this article resemble the corresponding structure of C. marchesonii , C. neumanni and C. algidus sp. nov.; in these three species, the article is bent medially (almost at a right angle) in its proximal portion, and is almost straight for the rest of its length. Moreover, in C. marchesonii (cf. Cottarelli & Mura, 1983) and particularly in C. tauricus , it widens apically into a sort of “spoon-bill” lamina.

The shape of the proximal apophysis of this article (curved at its apex) and the small size seem to be characteristic of C. tauricus ; however, it is closest to the corresponding structure of C. neumanni , which has a curved apex but is much more developed. The proximal apophyses of C. weisigi and C. algidus sp. nov. also resemble the corresponding structure of C. tauricus . C. appendicularis differs because it has a well developed conical apophysis. C. skorikowi also has a similar apophysis (although very small), which is practically absent in C. marchesonii .

As mentioned previously, the apophysis of the basal article of the antenna does not correspond to the drawings made by Pesta, 1921. In both shape and size, it most closely resembles the corresponding structure of C. weisigi and C. skorikowi . In C. marchesonii , it appears more elongated and narrow, whereas in C. appendicularis and C. algidus sp. nov. the apophysis is more developed and more markedly conical. Finally, in C. neumanni , it is conical and as long as the proximal apophysis of the distal article.

The upper lamella of the antennal process resembles the corresponding lamellae of the other species discussed here; they all exhibit finger-like outgrowths of the medial inner margin that are more developed than the corresponding ones of the opposite margin. In C. tauricus , the upper lamella is half the length of the lower lamella, and in this feature is closest to C. weisigi . The morphology of the lower lamella, not described by Pesta, resembles that of the corresponding process of C. appendicularis (cf. Daday, 1910 and Brtek, 1966), C. algidus sp. nov., C. marchesonii , C. weisigi , C. skorikowi and C. neumanni . The last five species also exhibit the carina of the antennal process, absent in tauricus and appendicularis but present in many other taxa of the “ diaphanus ” group.

The females of C. tauricus are characterized by the peculiar ornamentation of the abdominal somites. Similar, albeit not identical, ornamentation occurs in C. skorikowi on the same number of somites. In C. neumanni , the number of ornamented somites is six, instead of five, and the last three of these metameres exhibit a pair of lateral bulges on each side, instead of one as in the other species. In contrast, this ornamentation is absent in the females of the other species discussed here. This can also be observed in other species of the “ diaphanus ” group, e.g. in the females of C. paphlagonicus Cottarelli, 1971 , another species from Turkey.

The brood pouch, short and swollen, resembles that of C. algidus sp. nov. in particular and partly also that of C. marchesonii .

Figures

FIGURE 1. Chirocephalus tauricus, male. A. lower lamella; B. upper lamella; C – D. second antenna

FIGURE 2. Chirocephalus tauricus, A – H. male. A. first maxilla; B. left mandible; C. enlarged detail of left mandible; D. right mandible; E. enlarged detail of the posterior tip of the right mandible; F. enlarged detail of the posterior ventral modified spine of the first maxilla; G. second maxilla; H. labrum, ventral.

FIGURE 3. Chirocephalus tauricus, A – G male. A. fist pair of thoracic limb; B. enlarged detail of the praeepipod of P 1; C. basal penes; D. eleventh pair of thoracic limb; E. eversible tip of hemipenis; F. enlarged detail of the endites of the sixth pair of thoracic limb; G. enlarged detail of the endopod of the sixth pair of thoracic limb.

FIGURE 4. Chirocephalus tauricus, A, C – J female, B, K male. A. ovisac; abdominal somites and cercopods, lateral; B. basal penes; C. female abdominal somites, dorsal; D – I, J. enlarged details of the verruciform outgrowths ornamenting the latero-posterior margin of the abdominal somites; H. compound eye, first and, second antenna; K. detail of male cercopods.