Archeosolenocera Carriol & Riou, 1991

Jauvion, Clément, Charbonnier, Sylvain & Bernard, Sylvain, 2017, A new look at the shrimps (Crustacea, Decapoda, Penaeoidea) from the Middle Jurassic La Voulte-sur-Rhône Lagerstätte, Geodiversitas 39 (4), pp. 705-716 : 710-714

Genus Archeosolenocera Carriol & Riou, 1991

Archeosolenocera Carriol & Riou, 1991: 145 . — De Grave et al. 2009: 14. — Schweitzer et al. 2010: 9.

TYPE SPECIES. — Archeosolenocera straeleni Carriol & Riou, 1991 , by monotypy.

ORIGINAL DIAGNOSIS BY Carriol & Riou (1991). — Rostre non bombé ventralement; sillon cervical court; sillon antennaire présent; flagelles antennulaires longs d’environ la moitié de la carapace; telson sans sillon dorsal médian.

LITERAL TRANSLATION. — Rostrum ventrally not rounded; short cervical groove; antennal groove present; antennular flagella of approximately half the carapace in length; telson without median dorsal groove.

EMENDED DIAGNOSIS. — Laterally flattened rostrum with suprarostral spines; epigastric spine antennal and pterygostomian spines; inclined cervical groove, not joined to the dorsal margin; antennal groove, widening towards antennal notch; elongate, subhorizontal hepatic groove; inferior groove directed frontward; hepatic spine; postorbital spine; long, very thin and delicate P4-P5.

DISCUSSION

Carriol & Riou (1991) placed Archeosolenocera within the Solenocerinae among the Aristeidae , but with unclear justification. Actually, their original diagnosis does not present any diagnostic characters (see literal translation above). Later, De Grave et al. (2009) placed Archeosolenocera within Aristeidae but without real justification. Schweitzer et al. (2010) followed this placement and indicated that Solenoceridae had no fossil representatives.

Our examination of the type material reveals that Archeosolenocera possesses anatomical characters typical of Dendrobranchiata Spence Bate, 1888 sensu Pérez Farfante & Kensley (1997), a subrectangular s2 not overlapping s1 pleuron, s1-s6 locked to each other by midlateral hinges, chelate P1-P3 ( Figs 3; 4 ). The key to the two superfamilies of the Dendrobranchiata ( Penaeoidea Rafinesque, 1815 and Sergestoidea Dana, 1852) proposed by Pérez Farfante & Kensley (1997) and updated by Tavares & Martin (2010) is based upon gill characters, which are not visible on fossil specimens. However, Archeosolenocera cannot be assigned within Sergestoidea due to its elongate rostrum (short in sergestoid shrimps, Figs3-5), its well-developed antennular flagellum (modified or absent in sergestoid shrimps, Fig. 4B ), and its well-developed P4 and P5 (reduced or absent in most sergestoid shrimps). Besides, the well-developed P1-P5 of Archeosolenocera indicates an affinity with the Penaeoidea ( Fig. 4C, D ).

According to the key to the families of the Penaeoidea proposed by Pérez Farfante & Kensley (1997), the presence of a postorbital spine in Archeosolenocera is a diagnostic character of Solenoceridae ( Figs 3; 5 ). Moreover, the carapace groove pattern ( Figs 3-5) is close to those observed in several solenocerid genera such as Cryptopenaeus De Freitas, 1979 , Mesopenaeus Pérez Farfante, 1977 and Solenocera Lucas, 1849 . The very elongate and thin P4-P5 ( Fig. 4C, D ) are also present in the solenocerid shrimps Hadropenaeus Pérez Farfante, 1977 , Haliporoides Stebbing, 1914 and Hymenopenaeus Smith, 1882 .

In conclusion, Archeosolenocera is to this date the sole fossil representative of Solenoceridae .

Archeosolenocera straeleni Carriol & Riou, 1991 ( Figs 3; 4 ; 5 )

Archeosolenocera straeleni Carriol & Riou, 1991: 146-148 , fig. 1, pl. 1, figs 1-3, pl. 2, figs 1-3. — Charbonnier 2009: 15, 17, 18, 158, 219, 221, 223, 230, figs 232, 238, 241, 379-382, 387, tables 14, 24, 25. — Charbonnier et al. 2010: 115, 121-123, 125, 129, figs 3, 4, 8, 9, tables 1-4; 2014: 375, 378, table 1. — Schweitzer et al. 2010: 9. — Robin et al. 2015a: 465, fig. 1a, b, table 1; 2015b: 490.

Antrimpos kiliani Van Straelen, 1923: 84-85 (partim), fig. 1; 1925: 67-70 (partim), fig. 40, pl. 1, fig. 3 (non figs 1, 2), pl. 2, fig. 1 (non fig. 2). — Roman 1928: 107, fig. 12, pl. 3, figs 2, 3. — Glaessner 1969: R447, fig. 252.1. — Pinna 1974: 13, 14, 19, fig. 3 — Schweitzer et al. 2010: 9.

“ Antrimpos ” secretaniae Carriol & Riou, 1991: 151-153 , fig. 3, pl. 4, figs 1-4, n. syn.

Antrimpos secretaniae – Fischer 2003: 241. — Charbonnier 2009: table 14. — Charbonnier et al. 2010: tables 1, 2; 2014: table 1 — Schweitzer et al. 2010: 9.

Antrimpos sp. – Van Straelen 1922: 982.

TYPE MATERIAL. — Holotype UJF-ID.1923 (coll. Gevrey); paratypes UJF-ID.1791 and 1793 (ex paralectotypes of A. kiliani , coll. Gevrey), MNHN.F.R61835, R61836, R61837, R61838, R61839, R61840, R61841, R61842, R61843 and R61851.

spine; i, inferior groove; lp, lateral process; m, muscle fibres; or, orbital spine; pg, pterygostomian spine; pl, pleopod; po, postorbital spine; r, rostrum; rs, rostral spines; s1-s6, pleonal somites 1 to 6; sc, scaphocerite; t, telson; vl fg, ventrolateral flagellum; 1st, first segment of antennular peduncle; 2nd, second segment of antennular peduncle; 3rd, third segment of antennular peduncle.Photographs: A, D, G, L. Cazes; H, J.-P. Cuif; B, C. Jauvion; F, P. Massicard (e-recolnat Project, MNHN). Line drawings: C. Jauvion. Scale bars: A, C-G, 20 mm; B, 2 mm; H, I, 10 mm.

TYPE LOCALITY. — Ravin des Mines, near La Boissine, La Voultesur-Rhône Lagerstätte, Ardèche, Rhône-Alpes, France.

TYPE AGE. — Early Callovian, Gracilis ammonite Zone.

ADDITIONAL EXAMINED MATERIAL. — Archeosolenocera straeleni . 19 ex paralectotypes of A. kiliani UJF-ID.1748, 1749 (3 specimens), 1756, 11897, 11898, 11900-11902, 11922, 14053-14059, 14061 and specimen UJF-ID.11907; MNHN.F. A32532 , A58275, A59351, MNHN.F.R61847, R61850, R61864. Antrimpos secretaniae . Holotype MNHN.F.R61868, paratypes MNHN.F.R61869, R61870, R61871.

DESCRIPTION

Carapace

Subrectangular carapace (holotype, CL = 40 mm; CH = 23 mm); short, strong, laterally flattened, rostrum with four suprarostral spines; straight dorsal margin with one epigastric spine at a third of CL; posterior margin dorsally concave with marginal ridge; ridged ventral margin (continuous with posterior margin ridge); anterior margin with antennal and orbital notches ventrally delimited respectively by antennal and pterygostomian spines; inclined cervical groove, not joined to the dorsal margin (interrupted at one third of CH), joined to straight antennal groove, widening towards antennal notch; elongate, subhorizontal hepatic groove, joined anteriorly to cervical and antennal grooves and stretching posteriorly until small ventral-directed inflexion in branchiocardiac region; wide straight inferior groove, frontward directed to antennal notch, joined to hepatic groove at level of hepatic spine (i.e. just posteriorly to junction of hepatic, cervical and antennal grooves); faint possible branchiocardiac groove of inclined sigmoidal shape revealed by a weak line on crushed carapaces, from the hepatic groove almost to dorsal margin; strong hepatic spine at the junction between cervical and hepatic grooves; strong postorbital spine above distal extremity of antennal groove.

Ornamentation of carapace

Carapace uniformly covered by small granules. Pleon

Subrectangular somites; s1-s6 with posterior margin showing median articulation among somites; s1 as large as s2 and s3; s1 pleura overlapping s2 pleura; long and subquadrate s6; s1-s6 terga and pleura uniformly covered with small granules; triangular telson, evenly covered with small granules, with a fixed median spine, posteriorly directed, on each outer margin, acute distal extremity; telson shorter than uropods.

Cephalic appendages

Prominent eyes (paratype MNHN.F.R61843, diameter = 8 mm for CL = 35 mm); antennula (a1) with strong antennular peduncle composed of three segments, first one displaying small granules as ornamentation, second and third ones almost equal in size, third segment bearing two flagella: wide and thick dorsolateral flagellum (diameter c. 3 mm), thin ventrolateral flagellum (diameter c. 0.5 mm) fixed on lateral process as long as the rest of third segment; both flagella of undetermined length; antenna (a2) with thick flagellum approximately as long as carapace, and elongate scaphocerite, dorsoventrally flattened, with deep dorsal longitudinal groove.

Thoracic appendages

Long, thin and smooth Mxp3 (longer than P1); slender chelate P1-P3, P2 longer than P1 and P3, P3 longer than P1; achelate P4-P5, very thin and delicate, longer than P2; P5 longer and thinner than P4; smooth P1-P5.

Pleonal appendages

Pleopods composed of elongate and strong protopod bearing two multiarticulated flagella (c. 30 segments) with setae; uropods longer than telson; uropodal endopod shorter than uropodal exopod; uropods with median deep groove, evenly covered with small granules; uropodal exopod with one row of setae on distal and inner margins.

DISCUSSION

Carriol & Riou (1991) described Antrimpos secretaniae based on four small specimens. However the examination of the type specimens reveals morphological characters diagnostic of Archeosolenocera ( Fig. 5 ): rostrum with suprarostral spines, epigastric spine; inclined cervical groove not joined to dorsal margin, antennal groove,subhorizontal hepatic groove, joined anteriorly to cervical and antennal grooves and stretching posteriorly, frontward directed inferior groove, strong hepatic spine at junction between cervical and hepatic grooves, postorbital spine. For all these reasons, we think that the type specimens of Antrimpos secretaniae are only small-sized or juvenile members of Archeosolenocera straeleni . Therefore, we consider them conspecific, the name A. straeleni being chosen as the valid name, based on the Principle of the First Reviser (ICZN 1999: article 24.2).

Figures

FIG. 4. — Archeosolenocera straeleni Carriol & Riou, 1991 from the La Voulte Lagerstätte: A, specimen MNHN.F.R61839 (paratype), left lateral view; B, specimen MNHN.F.R61837 (paratype), left lateral view; C, D, detail of specimen MNHN.F.R61837 (paratype), left lateral view (C) and line drawing (D); E, specimen MNHN.F.R61840 (paratype), left lateral view; F, specimen MNHN.F.R61842 (paratype),right lateral view; G, specimen MNHN.F.R61843 (paratype), left lateral view H-I, detail of specimen UJF-ID.1748 (coll.Gevrey),right lateral view (H) and line drawing (I). Abbreviations:ct, cephalothorax;en, pleopodal endopod;ex, pleopodal exopod; Mxp3, third maxilliped; P1-P5, pereiopods 1 to 5; pro, pleopodal protopod; set, setae; s6, pleonal somite 6; t, telson. Photographs: A, B, E-G, P. Massicard (e-recolnat Project, MNHN); C, H, C. Jauvion. Line drawings: C. Jauvion. Scale bars: A, B, E-G, 20 mm; B, C, 10 mm; H, I, 5 mm.

FIG. 5. — Archeosolenocera straeleni Carriol & Riou, 1991, from the La Voulte Lagerstätte. A, B, specimen MNHN.F.R61868 (holotype of Antrimpos secretaniae), right lateral view (A) and line drawing (B); C, specimen MNHN.F.R61870 (paratype of A. secretaniae), right lateral view.Abbreviations: α, hepatic spine; b, antennal groove; b1, hepatic groove; ct, cephalothorax; e1e, cervical groove; i, inferior groove; po, postorbital spine; r, rostrum; rs, rostral spines; s1-s6, pleonal somites 1 to 6; sc, scaphocerite; t, telson. Photographs: P. Massicard (e-recolnat Project, MNHN). Line drawings: C. Jauvion. Scale bars: 10 mm.