Stenodactylina shotoverigiganti, Devillez & Charbonnier, 2021

Devillez, Julien & Charbonnier, Sylvain, 2021, Review of the Late Jurassic erymoid lobsters (Crustacea: Decapoda), Geodiversitas 43 (2), pp. 25-73 : 60

Stenodactylina shotoverigiganti n. sp.

( Fig. 16 D-G)

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Eryma cf. bedelta – Woods 1930: pl. 21, fig. 2.

TYPE MATERIAL. — Holotype NHMUK 24559 .

ETYMOLOGY. — The specific epithet comes from the Latin “ gigantes ”, meaning giant, associated to the name of the type locality, Shotover. It refers to the giant of Shotover, a geoglyph, mentioned during the 17th century by Jean Aubrey, that has disappeared now.

TYPE LOCALITY. — Shotover, Oxfordshire, United Kingdom.

TYPE AGE. — Oxfordian.

DESCRIPTION

Carapace

Sub-cylindrical carapace; fusiform intercalated plate; elongated cardiac region; deep and wide cervical groove, becoming wider ventrally, slightly sinuous at its median inflexion, joined to dorsal margin and to antennal groove; deep and very wide antennal groove; short, shallow gastro-orbital groove, oblique, originating as a slight median inflexion of cervical groove; subparallel postcervical and branchiocardiac grooves, slightly curved; deep and wide postcervical groove, not joined to dorsal margin and interrupted in hepatic region; deep and wide branchiocardiac groove, becoming wider towards its junction to the hepatic groove, joined to dorsal margin, joined to the posterior extremity of the hepatic groove; wide hepatic groove, concavo-convex, joined to the cervical groove; slightly inflated ω area, ventrally delimited by a shallow depression extending between cervical and hepatic grooves; flat χ area; deep and wide inferior groove, joined to hepatic groove.

Ornamentation

Carapace covered by rounded tubercles; intercalated plate with small tubercles irregularly spaced; gastric region with an oblique row of tubercles ended by an orbital spine.

DISCUSSION

Stenodactylina shotoverigiganti n. sp. is known by a unique carapace previously mentionned and figured byWoods (1930) as Eryma cf. bedelta . Careful examination of the specimen shows the absence of junction between postcervical and branchiocardiac grooves, and the interruption of the postcervical groove in hepatic region while the branchiocardiac groove is joined to the hepatic groove. This groove pattern is diagnostic of Stenodactylina . Moreover, some morphological features allow the distinction of this specimen from all other representatives of the genus for which the carapace is known. Indeed, the postcervical groove is shorter than that of S. australis , S. delphinensis ( Moret, 1946) , S. deslongchampsi ( Van Straelen, 1925) , S. granulifera , S. lagardettei , S. pseudoventrosa , and S. walkerae ( Feldmann & Haggart, 2007) . It is also slightly curved contrary to S. burgundiaca ( Crônier & Courville, 2004) , S. delphinensis , S. granulif-era, S. triglypta , and S. walkerae . Only the ω area is inflated while it is flat in some species ( S. australis , S. delphinensis , S. deslongchampsi ) or both ω and χ areas are inflated in some others ( S. burgundiaca , S. granulifera , S. guisei ( Wright, 1881) , S. lagardettei ). The ornamentation of the specimen is thin and only made of tubercles contrary to S. australis , S. burgundiaca , S. delphinensis , S. granulifera , S. guisei , S. lagardettei , and S. pseudoventrosa . Finally, there is an orbital row, which is absent in S. australis , S. burgundiaca , S. delphinensis , S. deslongchampsi , S. guisei , and S. triglypta . Considering all these elements, we consider this specimen as a representative of a new species of erymid lobsters: Stenodactylina shotoverigiganti n. sp.

Figures

FIG. 16. — Stenodactylina insignis (Oppel,1862), Stenodactylina shotoverigiganti n. sp. and Stenodactylina granulifera (Secrétan,1964):A, holotype of S. insignis (Oxfordian, Haute-Saône, France); B, holotype MFN 2236 P1383/2 MB.A.1536 of Eryma anisodactylus Krause,1891 (Kimmeridgian, Holzen,Germany); C, specimen IRSNB without number of S. insignis (Kimmeridgian, La Rochelle, France); D-G, holotype NHMUK 24559 of S. shotoverigiganti n. sp. (Oxfordian, Shotover, United Kingdom):right lateral view (D), left lateral view (E), schema (F), dorsal view (G); H-J, holotype MNHN.F.R03975 of S. granulifera (Kimmeridgian,Antsalova, Madagascar): lateral view (H), schema (J); C, D, holotype MNHN.F.R03974 of Eryma madagascariensis Secrétan, 1964 (Kimmeridgian, Antsalova, Madagascar). Abbreviations:a, branchiocardiac groove;b, antennal groove; b1, hepatic groove; c, postcervical groove; d, gastro-orbital groove; e1e, cervical groove; i, inferior groove;ip, intercalated plate; χ, attachment site of adductor testis muscle;ω, attachment site of mandibular muscle.Photographs:A, L. Cazes;B-E, G,J. Devillez; H, J, C. Lemzaouda. Line drawings: J. Devillez. Scale bars: 1 cm.