Costacopluma grayi Feldmann & Portell 2007

Costacopluma grayi Feldmann & Portell, 2007 (Figs 14; 15; Table 1; Appendix 1F) Costacopluma grayi Feldmann & Portell, 2007: 92, figs2, 3.— Armstrong et al. 2009: fig. 6.2-6.3. — Martínez-Díaz et al. 2016: fig. 5.9-5.10. non Costacopluma grayi – Feldmann et al. 2014: 137, pls 1, 2. (Costacopluma nicksabani n. sp.). — Martínez-Díaz et al. 2016: figs 5.1- 5.8; 6.4. (Costacopluma nicksabani n. sp.). — Martínez-Díaz et al. 2016: figs 4; 6.4. — Vega et al. 2016: fig. 4G, H. TYPE MATERIAL. — Holotype. United States • 1 specimen; Alabama, Covington County, Below Point A Dam (31°21’32”N, 86°31’11”W), ALMNH loc. 4; Tallahatta Formation, NP14 nannofossil zone; Eocene (upper Ypresianlower Lutetian); UF 113749. Paratypes. United States • 1 specimen; same as for the holotype; UF 113748 • 1 specimen; idem; UF 113750 • 1 specimen; idem; UF 114747 • 1 specimen; idem; UF 115672 • 1 specimen; idem; UF 115793 • 1 specimen; idem; UF 115794 • 1 specimen; idem; UF 115795 • 1 specimen; idem; UF 115796. ADDITIONAL MATERIAL EXAMINED. — United States • 2 specimens; Alabama, Covington County, Below Point A Dam (31°21’32”N, 86°31’11”W), ALMNH loc. 4; Tallahatta Formation, NP14 nannofossil zone; Eocene (upper Ypresianlower Lutetian); ALMNH: Paleo:20598 • 1 specimen; idem; ALMNH: Paleo:21440 • 3 specimens; idem; MMNS IP-6491 • 1 specimen; idem; MMNS IP-6492 • 2 specimens; idem; MMNS IP-10046 • 1 specimen; idem; MMNS IP-11213 • 1 specimen; idem; UF 116615 • 1 specimen; idem; UF 116619 • 1 specimen; idem; UF 142615 • 1 specimen; idem; UF 142616 • 1 specimen; idem; UF 116691 • 1 specimen; idem; UF 171033 • 1 specimen; idem; UF 171034 • 1 specimen; idem; UF 256410 • 1 specimen; Alabama, Conecuh County, Pigeon Creek (T5N, R14E, Sec.20, NE¼,NE¼); Tallahatta Formation, NP14 nannofossil zone; Eocene (upper Ypresianlower Lutetian); UF 287265 • 1 specimen; idem; UF 287266 • 1 specimen; idem; UF 349284-349310. TYPE HORIZON. — Tallahatta Formation, NP14 nannofossil zone, Eocene (upper Ypresianlower Lutetian). TYPE LOCALITY. — Below Point A Dam (31°21’32”N, 86°31’11”W), Covington County, Alabama, United States. DIAGNOSIS. — Carapace relatively small (<15 mm maximum width), subrectangular, wider than long (l/w ratio c. 0.9), widest point posterior to mid-length. Fronto-orbital margin c. 70% of maximum width; lateral margins somewhat diverging posteriorly, fairly straight, but more convex posteriorly; posterior margin nearly straight. Rostrum inclined downward, slightly longer than wide, minimum width in dorsal view c. 4% of maximum carapace width. Outer orbital spine small, triangular, directed forward. Dorsal carapace containing three tubercular transverse ridges of narrow width on average, with rounded tops; anterior ridge sinuous, uninterrupted, diminishes toward but reaches lateral margins. Cardiac region raised, tubercular, with convex and flattened ridge anteriorly and raised extension axially directed posteriorly. Gentle swellings with tubercles just anterior to innermost part of posterolateral margins. MEASUREMENTS. — See Table 1. DESCRIPTION Referral is made to Feldmann & Portell (2007: 92). Additional specimens allow for improved description of rostrum, outer orbital spine, posterior margin, cheliped, sternum, and pleon. Outer orbital spine small, appears directed forward (UF 115796). Partial rostrum narrow, minimally c. 4% of maximum carapace width in dorsal view. Posterior margin with one row of small tubercles on top of rim, curving somewhat forward in lateral parts, nearly straight to very slightly concave in axial part (MMNS IP-11213, UF 171033). Outer side propodus (UF 287266) without tubercles as preserved, with a groove near base extending onto fixed finger, with at least four pits on fixed finger close to occlusal surface. Male sternite 4 with distinct, tubercular rim on outer side; less distinct rim on inner side, marking deep sternopleonal cavity for telson; generally smooth on cuticular surface in between. Somites male pleon unfused, with transverse, tubercular keels; telson with rounded tip. REMARKS Several papers ascribed early Danian and Maastrichtian specimens to this species (Feldmann et al. 2014; Vega et al. 2016; Martínez-Díaz et al. 2016), but there are several morphological differences between the specimens from the Eocene and these c. 18-19 million years older specimens that warrant species-level separation. For the early Danian specimens, referral is made to the new species erected below. The Maastrichtian specimens also represent a different species of Costacopluma not treated further herein: they have an outer orbital spine directed anterolaterally instead of forward as in C. grayi (UF 115796), are proportionally wider, and have a greater maximum size (see Vega et al. 2016; Martínez-Díaz et al. 2016). Specimens with light to dark brown cuticle are embedded in tan/light brown fine sediment with some sand. Others occur in tan-brown sediment with more sand embedded, and a very dark brown cuticle. Finally, some occur in dark gray sediment and have dark brown cuticle. This applies to specimens from Point A Dam and Pigeon Creek. Some are listed as found in situ (UF 116615, UF 116619, UF 116691) or found in bed 5 of Copeland (1966) (UF 171033, UF 171034, type series), but the preservation style differs. It is likely that specimens underwent somewhat different taphonomic histories. Some specimens (MMNS IP-11213 and MMNS IP-10046) are listed to have come from the basal Lisbon Formation in “Bed 5” of Copeland (1966), which Feldmann & Portell (2007) interpreted to be the Tallahatta Formation (see also Savrda et al. 2010). Additional specimens were briefly mentioned in a paper focused on the vertebrate fauna of Point A Dam (Clayton et al. 2013). Unfortunately, the whereabouts of those crabs is uncertain (pers. comm. AAK with the Chuck Ciampaglio, November 2023).