Eodromites bernchrisdomiorum, Klompmaker & Starzyk & Fraaije & Schweigert, 2020

Klompmaker, Adiël A., Starzyk, Natalia, Fraaije, René H. B. & Schweigert, Günter, 2020, Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura), Palaeontologia Electronica (a 32) 23 (2), pp. 1-54 : 6-7

Eodromites bernchrisdomiorum sp. nov.

Figure 2 B-E, H-K

zoobank.org/ 67AB3730-8635-40B1-A40A-9306798B7DA5

2015b Eodromites grandis (von Meyer, 1857) ; Starzyk, p. 6, fig. 4.

Diagnosis. Carapace slightly longer than wide (l/w ratio ~1.1), with fairly small maximum size up to ~ 10 mm long, ovate in shape, widest at hepatic or epibranchial region. Fronto-orbital margin only slightly smaller than maximum width. Ratio of length from outer orbital angle to cervical groove at lateral margin divided by length from tip of rostrum to cervical groove axially 0.28-0.34. Rostrum with broad base, triangular, downturned, with blunt tip, with axial concavity in dorsal view. Orbits moderately deep, wider than tall, anterolaterally oriented. Upper orbital margin without protrusion at outer orbital angle; shallow fissure in orbital margin at lateralmost part of lower orbital margin.

Etymology. Named after the brothers of AAK: Bernie, Christiaan, and Dominick Klompmaker.

Material studied. Holotype: I-F/ MP/6259 /1588/11; paratypes: I-F/ MP/6255 /1588/11, I-F/ MP/6258 / 1588/11; other material: I-F/ MP/1369 /1508/08, I-F/ MP/3526 /1533/08, I-F/ MP/3604 /1533/08, I-F/ MP/ 4874 /1534/08, I-F/ MP/4927 /1534/09, I-F/ MP/6257 / 1588/11, UF 272090 , UF 272100 .

Description. Carapace slightly longer than wide (l/ w ratio ~1.1), with fairly small maximum size up to ~ 10 mm long, ovate in shape, strongly vaulted in both directions, widest at hepatic or epibranchial region. Fronto-orbital margin only slightly smaller than maximum width. Ratio of length from outer orbital angle to cervical groove at lateral margin divided by length from tip of rostrum to cervical groove axially 0.28-0.34. Lateral margins distinctly rimmed anteriorly, less so at epibranchial regions, not rimmed at meso-metabranchial regions. Posterior margin slightly concave. Rostrum with broad base, triangular, downturned, with blunt tip, with axial concavity in dorsal view. Orbits moderately deep, wider than tall, anterolaterally oriented. Upper orbital margin without protrusion at outer orbital angle; shallow fissure in orbital margin at lateralmost part of lower orbital margin; lower orbital margin appears rectangular, not extending beyond upper orbital margin. Epigastric regions swollen, adjacent to tip mesogastric region. Protogastric and hepatic regions confluent. Subhepatic region bulbous. Mesogastric region triangular to pyriform, with pair of scabrous posterior gastric muscle scars at base ( Figure 2B ) and weak axial groove in between, best defined anteriorly and posteriorly, weakly so in middle part. Uro-metagastric region indistinct, wide, confluent with epibranchial regions. Large epibranchial regions somewhat swollen laterally. Cardiac region, weakly delimited, subtriangular to pentagonal, usually with three tubercles in triangle pointing posteriorly. Meso-metabranchial regions confluent, depressed laterally. Intestinal region appears depressed. Cervical groove moderately strong, sinuous, with gastric pits on both sides of axis, curving around subhepatic region on lateral side. Postcervical groove weak. Branchiocardiac groove strongest away from longitudinal axis, nearly transverse on dorsal side, bending forward on lateroventral side. Posterior margin with groove. Epibranchial pits not observed, pit on upper orbital margin sensu Starzyk (2015b) not consistently present. Internal mold with some tubercles. Cuticle, appendages, ventral side, and abdomen unknown.

Occurrence. Late Jurassic (Oxfordian) of southern Poland. Bzów (middle Oxfordian, transversarium Zone): I-F/MP/1369/1508/08, I-F/MP/3526/1533/ 08, I-F/MP/3604/1533/08. Niegowonice (middleupper Oxfordian, upper elisabethae -upper Wartae Subzone): I-F/MP/4874/1534/08, I-F/MP/4927/ 1534/09, I-F/MP/6255/1588/11. Ogrodzieniec (lower-middle Oxfordian, cordatum-transversarium Zone, with exception of the discontinuous mariae Zone): I-F/MP/6257/1588/11, I-F/MP/6258/1588/ 11, I-F/MP/6259/1588/11. Szklary (middle Oxfordian): UF 272090, UF 272100.

Dimensions. (In mm) I-F/MP/1369/1508/08: max. length excl. rostrum (L)=-, max. width (W)=4.7; I-F/ MP/6259/1588/11: L=10.2, W=9.3; I-F/MP/3526/ 1533/08: L=8.7, W=8.1; I-F/MP/3604/1533/08: L=10.3, W=9.8; I-F/MP/4874/1534/08: L=-, W=7.7; I-F/MP/4927/1534/09: L=-, W=7.2; I-F/MP/6255/ 1588/11: L=-, W=7.9; I-F/MP/6257/1588/11: L=3.8, W=3.6; I-F/MP/6258/1588/11: L=-, W=4.2.

Remarks. Compared to the type species, Eodromites grandis , the proportional distance from the outer orbital angle to the cervical groove is shorter than in E. grandis . This difference applies to all species of Eodromites except E. nitidus and E. rostratus (Appendix 1). The anterolateral margin anterior to the cervical groove is less curved compared to E. grandis , resulting in a proportionally wider occupation of the fronto-orbital margin of the maximum width. Moreover, the maximum size (length= 10 mm) and width (9 mm) based on 23 specimens (Starzyk, 2015b) is substantially smaller than that of E. grandis (e.g., Appendix 1). Eodromites bernchrisdomiorum sp. nov. has a proportionally shorter anterolateral margin anterior to the cervical groove, and the orbits are more anterolaterally oriented than in E. cristinarobinsae sp. nov. Furthermore, the fissure in the lower orbital margin near the lateralmost part of the margin in E. cristinarobinsae sp. nov. (MAB k2950, 2626, 3589; UF 271883) is narrower and more prominent than in E. bernchrisdomiorum (UF 272100, UF 272090, I-F/ MP/6259/1588/11, I-F/MP/6258/1588/11). We provide some additional differences per species here. Eodromites depressus has a proportionally narrower branchial region than the new species; E. dobrogea and E. polyphemi are more circular in outline in dorsal view; the drawing of E. nitidus exhibits more protruding lower orbital margins; the drawing of E. rostratus appears to have a less protruding rostral area; and E. rotundus shows a rostrum that is pointing more forwardly. The limited number of well-preserved specimens available does not allow for a detailed analysis of possible ontogenetic changes and intraspecific variation.

Figures

FIGURE 2. Specimens of the crab Eodromites spp. from the Late Jurassic of Europe. A, F, G, Eodromites grandis (von Meyer, 1857) from the Upper Jurassic (upper Kimmeridgian) coral limestones of Saal an der Donau in southern Germany in dorsal, frontal, and left-lateral views, resp. (SNSB-BSPG 2016 XXI 404). B-E, Holotype of Eodromites bernchrisdomiorum sp. nov. from the Upper Jurassic (lower-middle Oxfordian) deposits of Ogrodzieniec in southern Poland in dorsal, frontal, right-lateral, and orbital views, resp. (I-F/MP/6259/1588/11). E, an oblique view of right orbital structure, primarily the lateral margin with a wide fissure. H-K, Late Jurassic (Oxfordian) Eodromites bernchrisdomiorum sp. nov. from southern Poland in dorsal view (H, I-F/MP/4874/1534/08, Niegowonice, middle-late Oxfordian; I, I-F/ MP/6255/1588/11, paratype, Niegowonice, middle-late Oxfordian; J, I-F/MP/6258/1588/11, Ogrodzieniec, early-middle Oxfordian, paratype; K, I-F/MP/1369/1508/08, Bzów, middle Oxfordian). L-O, Holotype of Eodromites polyphemi (Gemmellaro, 1869) from the Late Jurassic (Tithonian) of Sicily, Italy, in dorsal, frontal, right-lateral, and left-lateral views, resp. (MGUP-020.18). Scale bar width is 5.0 mm, except for E (1.0 mm).