Segonzackomaius Burukovsky 2011

Genus Segonzackomaius Burukovsky, 2011 Segonzackomaius Burukovsky, 2011: 1 (type species: Nematocarcinus burukovskyi Komai & Segonzac, 2005, by original designation). Remarks. For the diagnoses of Segonzackomaius, see Burukovsky (2011). Segonzackomaius can be easily distinguished from the other four genera of Nematocarcinidae by the presence of fixed teeth on both dorsal and ventral rostral margins and movable teeth along the post-rostral ridge (Burukovsky 2011, 2012, 2013). In addition, Segonzackomaius differs from Lenzicarcinus Burukovsky, 2005 in the longer rostrum reaching to or overreaching the tip of antennal scale, and lacking a dorsal carina on the third abdominal somite (Burukovsky 2005); from Macphersonus Burukovsky, 2012 in having fixed teeth on the ventral rostral margin, and a carapace with distinct postorbital, cervical and branchiocardiac grooves (Macpherson 1984; Burukovsky 2012); from Nematocarcinus in the absence of paired posteroventral spots on the sixth abdominal somite (Burukovsky 2011); and from Nigmatullinus Burukovsky, 1991 in the shorter telson (not exceeding the uropodal exopod) bearing paired dorsolateral spinules, and a smooth carapace without curved keel connecting subcardiac and hepatic regions (Pequegnat 1970; Burukovsky 1991). Key to species of Segonzackomaius Burukovsky, 2011 1. Dorsal margin of rostrum and post-rostral ridge with less than 11 teeth; third pleomere tergite not produced posteromesially; fifth pleuron with produced, acute posteroventral tooth; inner surface of fifth pleuron posteriorly without tubercle or ridge-like structure........................................................... S. burukovskyi (Komai & Segonzac, 2005) - Dorsal margin of rostrum and post-rostral ridge with more than 13 teeth; third pleomere tergite produced posteromesially; fifth pleuron with subacute posteroventral tooth; inner surface of fifth pleuron posteriorly with oblong or teardrop-shaped tubercle ................................................................................................... 2 2. Rostrum almost horizontal, about 0.90 times of carapace length, ventral margin armed with 5 teeth in distal 0.80; telson not reaching distal margin of uropodal endopod.......................................... S. altus (Spence Bate, 1888) - Rostrum ascending, about 0.65 times of carapace, ventral margin armed with 6–8 teeth in distal half; telson overreaching uropodal endopod........................................................................ S. sursus sp. nov.