Decapod Crustacea of the Californian and Oregonian Zoogeographic Provinces 3371 Author Wicksten, Mary K. text Zootaxa 2012 2012-07-04 3371 1 307 journal article 1175­5334 Key to species of family Benthesicymidae 1. Endopods of second maxillipeds slender. Usually benthic...................................................... 2 – Endopods of second maxillipeds with merus thin, broad, compressed. Usually pelagic.............................. 4 2. Posterior margin of abdominal somite 4 armed with comb-like denticles, teeth................. Benthesicymus laciniatus – Posterior margin of abdominal somite 4 not armed with comb-like denticles or teeth................................ 3 3. Median carina of abdominal somites 5, 6 terminating posteriorly in small acute tooth............... Benthesicymus tanneri – Median carina of abdominal somites 5, 6 not terminating in teeth; sixth somite ending in upturned transverse ridge............................................................................................. Benthesicymus altus 4. Podobranchs absent on pereopods 1–3. Telson with single pair mobile lateral spines................................. 5 – Podobranchs present on pereopods 1–3. Telson with more than single pair mobile lateral spines....................... 8 5. Female with orifices of seminal receptacles opening independently, not included in common atrium. Male with distolateral lobe of petasma undivided............................................................................... 6 – Female with orifices of seminal receptacles lying within common atrium. Male with distolateral lobe of petasma divided... 7 6. Female with subtriangular structure present between pereopods 4; two symmetrical protuberances transversely located just anterior of this structure from posterior margin of fifth thoracic sternite, male with external lobe of petasma undivided; distoventral lobe of petasma divided........................................................... Gennadas tinayrei – Female without such structure, male with external distoventral lobe of petasma undivided............. Gennadas sordidus 7. Female with thelycum provided with subrectangular, tong-shaped projection extending forward from between pereopods 4, reaching to posterior edge of thoracic sternite 6; male with external lobe of petasma much longer than median lobe............................................................................................... Gennadas incertus – Female without such subrectangular structure, but subtriangular structure on thoracic sternite 5, between pereopods 2; strong transverse crest on anterior part of sternite XIV. Male with external lobe of petasma shorter than median lobe................................................................................................. Gennadas propinquus 8. Cervical and post-cervical sutures not closely approaching each other on dorsal midline......... Bentheogennema borealis – Cervical and post-cervical sutures closely approaching each other on dorsal midline................................. 9 9. Petasma with large accessory lobe; in mature male, with terminal hook; thelycum with elevated triangular plate on sixth sternite.Telson with only 1 pair terminal-lateral spines.................................... Bentheogennema burkenroadi – Petasma with smaller accessory lobe, without terminal hook; thelycum without elevated triangular plate on sixth sternite.Telson with 1–3 pairs terminal-lateral spines............................................... Bentheogennema pasithea