Data from: Appraisal of the fossil record of Homarus (nephropid lobster), with description of a new species from the upper Oligocene of Hungary and remarks on the status of Hoploparia

The fossil record of the clawed lobster genus, Homarus, is appraised. The taxonomic history of Homarus and Hoploparia is summarized, and a list of species recognized for each is provided. A tabulation of all fossil species of the family Nephropidae permits assessment of nephropid species diversity through time. A new species of Homarus, H. hungaricus, is recorded from the upper Oligocene (Chattian) Mány Formation at Mány, northern Hungary. The species is known by a single specimen consisting of a partial cephalothorax, a pleon minus telson, and partial chelipeds. Homarus is now known by two extant species (H. americanus and H. gammarus) and six fossil taxa, one of Early Cretaceous (Albian; H. benedeni) and five of Cenozoic age (H. hungaricus n. sp., H. klebsi, H. lehmanni, H. morrisi, and H. percyi). The new fossil Homarus differs from modern congeners in aspects of carapace and pleon ornamentation and, especially, cutter claw shape. This is the fourth Oligocene occurrence of a nephropid species; all are Homarus and all are from Western Europe. Homarus makes its appearance in the fossil record in the Early Cretaceous (Albian) and then is not known again until the Paleogene, despite the fact that nephropid lobsters in general are well known from the Late Cretaceous. Nephropid lobsters are better known from the Cretaceous than from the Cenozoic. Both raw species numbers and numbers corrected (normalized) for epicontinental sea coverage show that shelf-dwelling nephropid lobsters were most diverse during the Late Cretaceous.

本研究对螯龙虾属（Homarus）的化石记录进行了系统评述。梳理了螯龙虾属与霍普螯龙虾属（Hoploparia）的分类学历史，并列出了二者所认可的有效物种清单。通过对海螯虾科（Nephropidae）所有化石物种的统计制表，得以评估该科物种随时间推移的多样性变化。本次研究报道了产自匈牙利北部马尼地区渐新统上部（恰特期）马尼组的螯龙虾属一新种——匈牙利螯龙虾（H. hungaricus），该物种仅知一件标本，包含部分头胸甲、不含尾节的腹体节以及部分螯足。目前已知螯龙虾属共有2个现生种（美洲螯龙虾H. americanus与欧洲螯龙虾H. gammarus）以及6个化石类群：1个早白垩世（阿尔布期；H. benedeni）类群，其余5个均为新生代类群（匈牙利螯龙虾H. hungaricus 新种、H. klebsi、H. lehmanni、H. morrisi及H. percyi）。这一新发现的化石螯龙虾与现生同属物种在头胸甲、腹体节的纹饰特征，尤其是切缘螯的形态上存在显著差异。这是海螯虾科物种在渐新世的第四笔化石记录，所有此类记录均隶属于螯龙虾属，且均发现于西欧地区。尽管海螯虾科龙虾类群在晚白垩世的化石记录较为丰富，但螯龙虾属的化石记录最早出现于早白垩世（阿尔布期），之后直至古近纪才再度有相关化石被发现。相较于新生代，海螯虾科龙虾类群的化石记录在白垩纪更为丰富。无论是原始物种数量，还是针对陆表海覆盖范围进行校正（标准化）后的物种数量，均显示栖息于陆架环境的海螯虾科龙虾在晚白垩世达到了物种多样性峰值。