Hoploparia beyrichi Schlüter, 1862

Tshudy, Dale M., Hyžný, Matúš, Veselská, Martina Kočová & Jagt, John W. M., 2022, Taxonomic revision of the extinct clawed lobster genus Oncopareia Bosquet, 1854 (Decapoda, Astacidea, Nephropidae), Palaeontologia Electronica (a 20) 25 (2), pp. 1-31 : 19-21

Hoploparia beyrichi Schlüter, 1862

Figure 1E , 2B–C , 10A–M

Partim 1854 Oncopareia bredai Bosquet , p. 127, pl. 10, figs. 6, 7, 71 [not pl. 10, figs. 5, 61]

1862 Hoploparia beyrichi Schlüter , p. 721, pl. 13, fig. 4.

1886 Homarus bredai (Bosquet) ; Pelseneer, p. 164, figs. 2, 3.

1929 Hoploparia bredai (Bosquet) ; Glaessner, p. 216.

1941 Oncopareia bredai Bosquet ; Mertin, fig. 9 e [pleon only].

1993 Hoploparia beyrichi Schlüter ; Tshudy, figs. 17.1–17.14.

2000b Hoploparia beyrichi Schlüter ; Tshudy and Sorhannus, fig. 2.3.

2010 Hoploparia beyrichi Schlüter ; Schweitzer et al., p. 28.

2018 Hoploparia beyrichi Schlüter ;Tshudy et al., p. 182.

Material examined. Holotype, Museum für Naturkunde Berlin, MB. A. 209; also several specimens deposited in the IRScNB collections, including those in the Bosquet ( IG 4285 ; IRScNB 90-33a, c, g, i), De Jaer ( IG 8261 ; IRScNB 90-24a, b) and Ubaghs ( IG 6521 ; IRScNB 90-19j, n, 90-20, 90- 22b, 90-32b, d, f and 90-39c) collections.

Diagnosis. Cephalothorax with little relief; antennal carina absent. Postorbital and supraorbital spine prominent; supraorbital followed by short carina. Pleonal terga and pleura with little relief; surfaces pitted. Claws slightly unequal in form and size.

Description. Carapace laterally compressed, twice as long as high. Postcervical groove intersecting dorsal midline at just posterior to mid-length on carapace. Postcervical groove extending transversely across dorsal surface; combined branchiocardiac and postcervical groove extending anteroventrally to level of antennal groove in slightly concave-forward arc; well impressed dorsally, becoming progressively fainter ventrally. Anterior extension of postcervical groove extending toward, but not reaching, middle of cervical groove. Hepatic groove very subtle or absent. Cervical groove subparallel to, and more vertical than, postcervical groove; originating at level of base of orbit. Cervical and antennal grooves together forming a semicircular arc. Antennal groove anteriorly curving upward, reaching carapace margin well below antennal spine. Branchiocardiac groove very short on most specimens, long on the single large specimen. Supraorbital spine followed by short carina. Postorbital spine round. Wide, flat, posteromarginal carina with elongate pits dorsally, smooth or pitted laterally. Surface of thoracic region with transversely elongate pits dorsally and laterally, granules ventrally.

Pleon laterally compressed. Terga rectangular, strongly convex, sparsely pitted. Pleura long, more densely pitted than terga. Pleuron 2 quadrate; anterior margin rounded, anteroventral corner rounded, ventral margin straight, posterior margin recurved, posteroventral corner terminating in posteriorly directed point. Pleura 3–5 cordate, terminating in point; pleuron 6 triangular. Pleura gently inflated axially, traversed by very broad, subtle, oblique ridge extending posteroventrally from anterodorsal corner of pleuron; carina most pronounced on second pleuron and becoming progressively less obvious on posterior segments. Pleura directed posteriorly relative to terga. A single, large pit present posteroventrally on pleuron 2, anteroventrally on pleura 3–5.

Claws slightly unequal in form and size. Right palm larger than left; right palm slightly longer than wide; left palm slightly more elongate. Palms widening distally; rapidly so near proximal articulation. Right palm upper surface gently convex; pitted proximally, but most of surface with flat, scale-like granules of varying size; pits along distal edges of most scales. Lower surface slightly more convex than upper surface, mostly pitted. Inner margin angular, slightly upturned, with at least four large, conical, slightly upturned spines; all but most proximal spine directed slightly distally; space between spines increasing distally. Outer margin angular, pitted.

Left palm upper surface gently convex, pitted. Lower surface convex, with very fine, very low, transversely elongate granules. Inner margin angular, with at least four large, conical, slightly upturned spines; all but most proximal spine directed distally. Outer margin broadly rounded proximally, becoming progressively narrower distally; sharply rounded at base of fixed finger.

Remarks. The holotype from the upper Maastrichtian (Kunrade Formation) of Kunrade, southern Limburg, the Netherlands, consists of an imperfectly preserved cephalothorax lacking the rostrum and a slightly better-preserved pleon lacking the telson. Schlüter (1862, p. 722) considered the specimen distinct from O. bredai , mainly on the basis of its carapace grooves and ornamentation and named it Hoploparia beyrichi . The pleons and claws that Bosquet (1854) described, illustrated and referred to Oncopareia bredai also belong to H. beyrichi ; thus, some specimens from the syntype collection of O. bredai actually belong to H. beyrichi . Bosquet’s figure 6 depicts the pleon of IRScNB 90-33a, and figure 7 the major claw, IRScNB 90-33c. Figure 71 a–b may correspond to IRScNB 90-24b; if not, the palms are very similar. Cephalothoraxes IRScNB 90-24a and 90- 33g are referred to H. beyrichi as well.

The cephalothoraxes of H. beyrichi and O. bredai are strikingly similar considering the fundamental differences between the pleons and claws of the two species. There are, however, consistent differences between them. First, the hepatic groove is deeper in O. bredai than in H. beyrichi . Schlüter (1862, p. 722) described, in different terms, that the hepatic groove circumscribed the protuberance “Χ” on O. bredai but not on his new species, H. beyrichi . Secondly, the cervical groove on O. bredai more nearly parallels the ventral portion of the branchiocardiac groove than on H. beyrichi . Finally, O. bredai is ornamented with granules, whereas H. beyrichi is covered dorsally and laterally with pits. Schlüter (1862, p. 722) noted that H. beyrichi lacked granules but was ornamented with an extremely fine sculpture.

Range and occurrence. Upper Maastrichtian of Belgium and the Netherlands.

Figures

FIGURE 1. Morphology of cephalothorax and a general habitus of studied taxa. A, Cephalothorax of nephropid lobsters with selected morphological characters (modified from Tshudy and Sorhannus, 2003). B, Habitus of thaumastocheliform lobsters, exemplified by Thaumastocheles zaleucus (from Calman, 1911). C, Habitus of ctenochelid ghost shrimps, exemplified by Ctenocheles balssi (from Kishinouye, 1926). D, Groove pattern of Oncopareia bredai Bosquet, 1854 (redrawn from Tshudy and Sorhannus, 2000b, fig. 2.2). E, Groove pattern of Hoploparia beyrichi Schlüter, 1862 (redrawn from Tshudy and Sorhannus, 2000b, fig. 2.3).

FIGURE 2. Oncopareia bredai (sensu Bosquet, 1854), as a composite species. A, Cephalothorax of O. bredai (from Bosquet, 1854, pl. 10, fig. 5). B, Pleon of Hoploparia beyrichi Schlüter, 1862 (from Bosquet, 1854, pl. 10, fig. 6). C, Claw of H. beyrichi (from Bosquet, 1854, pl. 10, fig. 71b). D, Composite drawing from Mertin (1941, text-fig. 9e). E, Pleonal segments 1 and 2 of O. bredai (as Homarus bosqueti Pelseneer, 1886; from Pelseneer, 1886, fig. 4).

FIGURE 7. Nymphaeops coesfeldiensis Schlüter, 1862 (= Oncopareia bredai Bosquet, 1854, as here understood). A, Incomplete cephalothorax with associated pleon in lateral view (from Schlüter, 1862, pl. 13, fig. 3). B, Cephalothorax and pleon in dorsal view (from Schlüter, 1862, pl. 13, fig. 6). C, Reconstruction of cephalothorax in dorsal view (from Schlüter, 1879, pl. 15, fig. 2). D, Near-complete individual in lateral view (from Schlüter, 1879, pl. 15, fig. 1). E, Cephalothorax and pleon in lateral view (from Mertin, 1941, text-fig. 9a). F, Pectinate claw (from Mertin, 1941, text-fig. 10k). G, Crusher claw (from Mertin, 1941, text-fig. 10b). H, Crusher claw (from Mertin, 1941, text-fig. 10d). Nymphaeops coesfeldiensis Schlüter, 1862 (= Oncopareia bredai Bosquet, 1854, as here understood) from the Vaals Formation (lower Campanian) at the former CPL SA quarry, Haccourt, north-east Belgium (I–K). I, Near-complete cephalothorax with associated appendages in lateral view (NHMM JJ 9974). J, Crusher claw (NHMM HB 393). K, Fingers of pectinate claw (NHMM HB 756). Figure parts A–H not to scale.

FIGURE 10. Hoploparia beyrichi Schlüter, 1862; upper Maastrichtian (Kunrade Formation), Kunrade area, southern Limburg, the Netherlands. A, Pleon in lateral view (from Bosquet, 1854, pl. 10, fig. 6). B, Right claw in inner and outer lateral views (from Bosquet, 1854, pl. 10, fig. 71). C, Incomplete right claw (from Bosquet, 1854, pl. 10, fig. 7). D, E, Pleon in dorsal (D) and lateral (E) views (IRScNB 90-32f). F–H, Fragmentary claw (right propodus) in inner lateral (F), outer lateral (G) and dorsal (H) views (IRScNB 90-19j). I, Cephalothorax with associated incomplete pleon in lateral view (IRScNB 90-32d). J, Right claw (propodus and carpus) in inner lateral view (IRScNB 90-24b). K, Cephalothorax with associated pleon (holotype, MB. A. 209). L–M, Cephalothorax in lateral (L) and dorsal (M) views (IRScNB 90- 33g). Specimens were whitened with ammonium chloride prior to photography.