Stenodactylina Beurlen, 1928

Devillez, Julien, Charbonnier, Sylvain, Hyžný, Matúš & Leroy, Lucien, 2016, Review of the Early Cretaceous erymid lobsters (Crustacea: Decapoda) from the Western Tethys, Geodiversitas 38 (4), pp. 515-541 : 522-524

Genus Stenodactylina Beurlen, 1928

( Fig. 1 D-F)

Stenodactylina Beurlen, 1928: 175 . — Glaessner 1969: 456. — Schweigert 2013: 411.

Erymastacus Beurlen, 1928: 171 . — Secrétan 1964: 71. — Glaessner 1969: 456. — Hyžný et al. 2015: 375.

TYPE SPECIES. — Stenodactylina liasina Beurlen, 1928 by monotypy.

EMENDED DIAGNOSIS. — Fusiform intercalated plate; very wide, deep cervical groove, joined to dorsal margin and to antennal groove; short gastro-orbital groove originating as a slight median inflexion of cervical groove; postcervical and branchiocardiac grooves nearly parallel; narrow postcervical groove, not joined to branchiocardiac groove and interrupted in hepatic region; branchiocardiac groove strongly inclined, joined to hepatic groove; concavo-convex hepatic groove, joined to cervical groove; inferior groove convex posteriorly, joined to hepatic groove; chelate P1; P1 propodus rectangular or trapezoidal, adorned with rows of spines and tubercles; P1 propodus with inner margin more compressed than outer margin; wide P1 dactylar bulge; P1 with extremely long and slender fingers, equal in length; P1 chela (form I; Fig. 1E ) with strong, rectangular or trapezoidal propodus, with straight or sinuous fingers, strongly narrowing immediately after their basis; outer margin convex at the base of fixed finger; P1 chela (form II; Fig. 1F ) with trapezoidal propodus, outer margin straight or convex, straight fingers, narrowing gradually to their distal extremity.

DISCUSSION

Beurlen (1928) defined two genera based on fragments of chelipeds, namely Erymastacus and Stenodactylina . Later, Erymastacus , with Glyphea ornati Quenstedt, 1857 as type species (subsequent designation by Glaessner 1929) was regarded by many authors as a junior synonym of Eryma ( Förster 1966; Glaessner 1969; Schweitzer et al. 2010) while other authors considered it as a distinct genus ( Secrétan 1964; Schweigert et al. 2000; Schweigert & Garassino 2003; Hyžný et al. 2015). Hyžný et al. (2015) provided arguments in favor of the resurrection of Erymastacus , once considered as junior subjective synonym of Eryma , and the synonymisation of Stenodactylina with Erymastacus . Their study was based on new material of Erymastacus lagardettei Hyžný et al., 2015 (Middle Jurassic of Belmont, France), which was considered to be the only record in which Stenodactylina - type chelipeds are associated with their carapaces.

Careful examination of the lectotype of Glyphea ornati Quenstedt, 1857 , leads us to a different conclusion. Indeed, this species clearly exhibits Eryma -like chelae (near-isochelous) instead of Stenodactylina -like chelae (distinctly heterochelous). In conclusion, we agree with Förster (1966), Glaessner (1969), and Schweitzer et al. (2010), we maintained the synonymy between Erymastacus and Eryma , and the combination Eryma ornatum (Quenstedt, 1857) is reinstalled. Finally, the concept of “ Erymastacus ” based on carapace and chelipeds proposed by Hyžný et al. (2015) is correct and should be renamed as “ Stenodactylina ”.

SYSTEMATIC IMPLICATIONS

According to Hyžný et al. (2015), we consider that several species fit the concept of Stenodactylina (ex Erymastacus ) such as:

1) Eryma insignis Oppel, 1862 ; this species shows P1 chela with length and shape close to that of Eryma anisodactyla Krause, 1891 . We consider that E. anisodactyla is a junior synonymous of E. insignis and we propose the new combination Stenodactylina insignis ( Oppel, 1862) , n. comb.;

2) Erymastacus australis Secrétan, 1964 ; this species shows P1 chela exhibiting a rectangular propodus, a wide inflated dactylar bulge and slender fingers. These features support the placement in Stenodactylina . We propose the new combination Stenodactylina australis ( Secrétan, 1964) , n. comb.;

3) Eryma falsani Dumortier, 1867 ; this species is known by a P1 chela showing a rectangular propodus, long and slender fingers and a row of coarse tubercles on dorsal surface of propodus. These characters support the assignment to Stenodactylina . Hence, we propose the new combination Stenodactylina falsani ( Dumortier, 1867) , n. comb.;

4) Stenodactylina lagardettei ( Hyžný et al., 2015) n. comb. exhibits P1 chelae typical of Stenodactylina .

Contrary to Hyžný et al. (2015), we consider that several species do not fit the concept of Stenodactylina (ex Erymastacus ) such as:

1) Eryma babeaui Étallon, 1861 ; this species possesses P1 chela typical of Eryma with trapezoidal propodus showing two longitudinal depressions and fingers curved inward and gradually narrowing distally;

2) Eryma major Oppel, 1861 ; this species was synonymized with Eryma modestiforme ( Schlotheim, 1822) by Garassino & Schweigert (2006). However, the holotype exhibits a dentition of the fingers different from that in E. modestiforme . Eryma punctatum Oppel, 1861 has the same dentition, so E. major is probably a large specimen of E. punctatum ;

3) Erymastacus quenstedti Beurlen, 1928 ; this species exhibits P1 chela typical of Eryma with trapezoidal propodus and fingers curved inward and gradually narrowing distally. According to Schweitzer et al. (2010), we maintain the placement in Eryma ;

4) Eryma aalensis (Quenstedt, 1857) ; this species exhibits P1 chela typical of Eryma with trapezoidal propodus showing two longitudinal depressions and fingers curved inward and gradually narrowing to distal extremity.

Hyžný et al. (2015) did not list several species, which we consider here to be representatives of Stenodactylina such as:

1) Enoploclytia armata Secrétan, 1964 ; this species shows P1 chela exhibiting a strong rectangular propodus, with inner margin more compressed than outer margin, rows of coarse tubercles in dorsal and ventral surfaces and on inner margin, and a wide inflated dactylar bulge. These features support the placement in Stenodactylina . We propose the new combination Stenodactylina armata ( Secrétan, 1964) n. comb.;

2) Enoploclytia triglypta Stenzel, 1945 ; this species exhibits a carapace groove pattern with postcervical groove not joined to branchiocardiac groove and interrupted in hepatic region. These features support the placement in Stenodactylina . We propose the new combination Stenodactylina triglypta ( Stenzel, 1945) n. comb.;

3) Eryma burgundiacum Crônier & Courville, 2004 ; this species exhibits a carapace groove pattern with postcervical groove not joined to branchiocardiac groove and interrupted in hepatic region. These features support the placement in Stenodactylina . We propose the new combination Stenodactylina burgundiaca ( Crônier & Courville, 2004) n. comb.;

4) Eryma granuliferum Secrétan, 1964 ; this species exhibits a carapace groove pattern with postcervical groove not joined to branchiocardiac groove and interrupted in hepatic region (see Charbonnier et al. 2012a: fig. 10). These features support the placement in Stenodactylina . We propose the new combination Stenodactylina granulifera ( Secrétan, 1964) n. comb.;

5) Eryma villersi Morière, 1883 ; the carapace groove pattern (postcervical groove not joined to branchiocardiac groove, interrupted in hepatic region) and the P1 chelae (elongate propodus, elongated, slender fingers) support the assignment to Stenodactylina . Hence, we proposed the new combination Stenodactylina villersi ( Morière, 1883) n. comb.;

6) Erymastacus strambergensis Bachmayer, 1959 ; this species shows P1 chela exhibiting a propodus with inner margin more compressed than outer margin, a row of coarse tubercles on inner margin, an inflated dactylar bulge, and a slender index basis. These features support the placement in Stenodactylina . We proposed the new combination Stenodactylina strambergensis ( Bachmayer, 1959) n. comb.;

7) Eryma walkerae Feldmann & Haggart, 2007 ; this species exhibits a carapace groove pattern with postcervical groove not joined to branchiocardiac groove and interrupted in hepatic region. These features support the placement in Stenodactylina . We propose the new combination Stenodactylina walkerae ( Feldmann & Haggart, 2007) n. comb.;

8) Eryma deslongchampsi Van Straelen, 1925 ; this species exhibits a carapace groove pattern with postcervical groove not joined to branchiocardiac groove and interrupted in hepatic region associated with a P1 chela with an elongate propodus and elongated, slender fingers. These features support the placement in Stenodactylina . We propose the new combination Stenodactylina deslonchampsi (Van Straelen, 1924) , n. comb.

Figures

FIG. 1. — Line drawings of carapaces and P1 chelae of Early Cretaceous erymid lobsters from Western Europe: A-C, Eryma Meyer, 1840: carapace (A), P1 chela form I (B), P1 chela form II (C); D-F, Stenodactylina Beurlen, 1928: carapace (D), P1 chela form I (E), P1 chela form II (F); G-H, Palaeastacus Bell, 1850: carapace (G), P1 chela (H); I-J, Enoploclytia M’Coy, 1849: carapace (I), P1 chela (J); K-L, Pustulina Quenstedt, 1857: carapace (K), P1 chela (L); M, Tethysastacus n. gen.: carapace. Abbreviations: a, branchiocardiac groove; b, antennal groove; b1, hepatic groove; c, postcervical groove; cd, cardiac groove; d, gastro-orbital groove; e1e, cervical groove; i, inferior groove; ip, intercalated plate; PoA, post-orbital area; ω, attachment site of mandibular muscle; χ, attachment site of adductor testis muscle. Line drawings: J. Devillez and S. Charbonnier.