reasonable to assume that Knightia and junior homonym of Clupea humilis Diploymstus migrated up the streams von Meyer (1848), so he substituted into the fresher water to spawn and grad­ the name Knightia eoeaena. According ually adapted to the fresh water habitat, to the rules of nomenclature, Jordan did filling an available ecological niche in the not have the authority to change the Green River lakes. They adapted very species name; Cope (1879, 1884), as well, indeed, and became the most the first reviser, had already included successful fish of the Green River lake this taxon in the genus Diplomystus, system. Knightia is known from the where it was no longer a homonym. Paleocene and Eocene of North America Therefore, the valid name of this species and the Cretaceous and Eocene of South is Knightia humilis (Leidy 1856), and K. America. Diploymstus is known from eoeaena is rejected as a junior synonym. Cretaceous (about 80 million years be­ Cope's (1884) changing of the trivial fore present) marine deposits of south­ . name alta to altus was apparently a ern Europe, Syria, and Brazil, and Terti­ gender change to coincide with his ary deposits of both North and South changing of the genus Clupea to Diplo­ America, Africa, and the Isle of Wight mystus. When Jordan (1907) put this (Thorpe, 1938). The Green River Forma­ species in the genus Knightia, he changed tion represents the earliest known occur­ the gender of the trivial name back to rence of Diploymstus in fresh water. Leidy's Oliginal (1877) spelling, alta. GENERIC ETYMOLOGY Both Knightia and Diplomystus are in need of rigorous redescription. Knightia: named in honor of the paleon­ tologist Wilbur Clinton Knight. KNIGHTIA Jordan 1907 Diplomystus: diplo - double, mystus - hidden or recessed. The gender is The species of Knightia are very poorly masculine. understood, considering its abundance. Specific differences described by Leidy NOMENCLATURE, SPECIFIC (1856; 1873) and Cope (1870; 1877; INFORMATION, REPOSITORIES, 1884) are on the basis of body depth AND SUGGESTED REFERENCES alone. Cope (1884, page 79) states, "It The first described fish from the Green [K. alta] is distinguished from D. hum­ River Formation was Clupea humilis ilis [now called K. humilis] by the (Leidy, 1856), which was changed to greater relative depth of the body, Diplomystus humilis by Cope in 1877. resembling in this respect the D. pee tor­ Cope described several species of Diplo­ osus. The difference which it presents mystus (1877; 1884) and divided all of in this respect is rather too great to the species into two main sections. permit its union with D. humilis," Jordan (1907) recognized the difference though he admits that intermediate between these sections and broke off forms can be found. On the basis of the D. humilis - D. alta section into a Leidy's and Cope's specimens, the rela­ new genus, Knightia. tive body depth difference between K. humilis and K. alta is quantified here. Jordan (1907) found the name Clupea humilis Leidy (1856) to be a Tanner's (1920) K. eopei (an F-l 86 specimen) is synonymous with K. alta. in Leidy, 1873, plate XVII, figure 1); The holotype for K. copei (UU.11) is USNM 4022 (illustrated in Cope, 1884, lost, and this decision is based on photo­ plate X, figure 4); UMVP 1180-B; UMVP graphs. Tanner described the single in­ 1180-E; UMVP 6591; SMMP 64,2.37; complete specimen (lost holotype UU.11, SMMP 2-A-2569; SMMP 43-2019; SMMP illustrated in Tanner, 1920, plate III, 1058.1; SMMP 2-A-2570; SMMP 2-A- figure 6) as having a greater caudal 2571; SMMP 2-A-2573; SMMP 78.9.9; peduncle depth and more dorsal rays SMMP 78.9.10;and LG 7.1 (figure 11.37). (15) than K. alta. Tanner probably in­ Fin Rays: Pectoral 10-14 (n=9); Pelvic cluded accessory rays or counted split 6-8, usually 6, with the first ray un­ rays (lepidotrichia) as two rays in his branched (n=10); Anal 13 or 14 major dorsal count. Careful examination shows (n=12, X=13.67, SD=.49), usually 14. his specimen to have 11 principle dorsal The first major ray is unbranched and is rays, as do K. humilis and K. alta. Leidy the longest anal ray. It is followed by 12 (1856) also mistakenly described K. or 13 branched rays. The last anal ray is humilis (under the name of Clupea often doubled. The major anal rays are humilis) as having 15 dorsal rays, but preceded by two accessory rays, the first later (1873) revised this to 13, and Cope of which is very small and unsegmented. ultimately (1884) found the count to be The last (second) accessory ray is seg­ I,ll. Caudal peduncle depth (as a spe­ mented near the distal end and is about cific character for K. copei) is no greater half to two-thirds the length of the first on Tanner's specimen than on several of major ray (the segmented tip is some­ Cope's (1884) figured specimens of K. times broken off, giving it a slightly alta. No characters were found to dis­ shorter appearance). Dorsal 11 or 12 tinguish UU.11 from K. alta. major (n=12, X=11.16, SD=.39), usually For additional descriptive information 11. The first major ray is unbranched see Cope, 1870; 1877; 1884. The caudal and is the longest dorsal ray. It is fol­ skeleton of Knightia is drawn in Taverne lowed by 10 or 11, usually 11, branched (1975, figure 1; 1976, figure 8). rays. The last dorsal ray is often doubled. The major dorsal rays are preceded by KI'!IGHTIA HUMILIS (Leidy 1856) two accessory rays, the first of which is = Clupea humilis Leidy 1856; Clupea very small and unsegmented. The last pusilla Cope 1870; Diplomystus humilis (second) accessory ray is segmented near Cope 1877*, and Knightia eocaena the distal end and is about half to two­ Jordan 1907. thirds the length of the first major ray (the segmented tip is sometimes Knightia humilis is the most common broken off, giving it a slightly shorter species of Knightia in Fossil Lake (F-1 appearance). Caudal, usually 1,9,8,1, and F-2). forked (n=16). The following information is based on Pterygiophores: Anal 13-14, usually 14 USNM 87 (holotype, missing; illustrated (n=13, X=13.77, SD=.44); Dorsal 11-12, usually 12 (n=l1, X=11.83, SD=.39). * Als o referred to as Lithichthys pusillus in Cope, 1871a. Cope (1884) synonymized this Vertebrae: Caudal about 13-15 (n=15, species with "Diplomystus humilis." X=14.33, SD=.82); Precaudal (2 PD) 87 21-24 (n=14, X=23, SD=1.48); Total KNIGHTIA AL TA (Leidy 1873) 36-38 (n=9), usually 37 (n=7). Neither Cope nor Leidy included predorsal = Clupea alta Leidy 1873; Diplomystus vertebrae in their counts. altus Cope 1877; and Knightia copei Tanner 1920. Scales: Cycloid. Scale rows along verte­ bral column about 34-35 (SMMP 78.9.9); Whereas K. humilis is the most com­ scale rows above vertebral column at mon species of Knightia in Fossil Lake, anterior end of dorsal fin about 3-4; K. alta is the most common Knightia scale rows below vertebral column at species in Lake Gosiute (G-l, G-2, G-3 greatest body depth about 5-7 (n=2). and G-4). Dimensions: Based on Leidy's (1873) The following information is based on type specimens and Cope's (1884) USNM 86 (holotype, missing; illustrated referred specimens, K. humilis is defined in Leidy, 1873, plate XVII, figure 2); here as those specimens with a standard­ AMNH 2688 (illustrated in Cope, 1884, length-to-body-depth ratio of greater than plate IX, figure 9); AMNH 2686 (illus­ 3 (body depth is less than one-third the trated in Cope, 1884, plate IX, figure standard length). 11); USNM 4019 (illustrated in Cope, Knightia humilis attains its largest 1884, plate X, figure 5); SMMP 78.9.12 size in the Fossil Lake quarries (F-l and (figure 1I.39); UMVP 6593 (two com­ F-2), where it reaches a total length of plete individuals on a slab); UMVP 6592; 25 em (10 inches). Maximum body depth SMMP 64.2.22; SMMP 64.2.36; SMMP about 25-31 percent of the standard 64.2.51; and LG 7.5 (figure 11.38). length (n=18), about 20-25 percent of Fin Rays: Pectoral 12-14 (n=5) ; Pelvic the total length (n=16); head length 6-7, usually 6, the first ray unbranched about 27-33 percent of the standard (n=4); Anal 13 to 15 major (n=7, length (n=17), about 21-25 percent of X=13.57, SD=.79). The first major ray the total length (n=16). is unbranched and is the longest anal ray. Other Information: At least one row of It is followed by 12 to 14 branched rays. tiny conical teeth on the maxilla and The last anal ray is often doubled. The dentary (n=5) (neither Cope nor Leidy major anal rays are preceded by two made mention of any teeth in their accessory rays, the first of which is very descriptions of Knightia). 10-12 (usually small and unsegmented. The last (second) 11) dorsal scutes between the skull and accessory ray is segmented near the dorsal fin (n=8). LG 7.1 (figure 11.37) distal end and is about half to two-thirds has some possible pigmentation preser­ the length of the first major ray (the vation in the skin. There was apparently segmented tip is sometimes broken off, a line of color spots running the entire giving it a slightly shorter appearance).