BU-L LETI N OF THE IllINOIS STATE LABORATORY OF NATURAL HIST'ORY URBANA, h.LlNOIS, U. S. A. VOL. VII. MAY, H)05. ARTJCLE IV. U'< A NEW SHOVELNOSE STURGEON FRO;\1 THE :\IlSSISSIl'l'l RIVUl. (PLATES lV.- VII. ) BY S. A. FORBES, PH .D., AND R.. E. RICHARDSON, A.N\' Article IV.—On a New Shoreliiose Stunjeon frotn the Mis- >;lsslppi Blver (Plates IV.— VII.). By S. A. Forbes and R. E. Richardson. In the course of our studies of the fishes of Illinois, made in connection with the preparation of a report upon the ichthy- olog}' of the state, it became necessary last year to examine gi-eater numbers of the larger species of the Mississippi River than could well be preserved in collections. Consequently, in June, 1904, Mr. Richardson visited for this purpose the fishing grounds at Clrafton, Illinois, at the mouth of the Illinois River, and the fish boats at Alton, where the catches from that part of the Mississippi and from the lower Illinois are mainly handled by the firm of Ashlock & Son, long established at that point. Mr. H. L. Ashlock of this firm expressed at this time his belief that a distinct sturgeon, known to the fishermen of the locality as the "white sturgeon," was occasionally obtained among the catches of the common shovelnose locally called the "switch- tail," an opinion presently confirmed by the receipt of one specimen of this species and the head of another, brought in by his fishing crews. Seven additional specimens have since been sent us by Mr. Ashlock, all taken in fyke-nets at or near Grafton. The failure of students of American ichthyology to distin- guish this species can be accounted for only on the supposition that specimens of it have never come to their notice, since its distinguishing characters are too obvious and important to have been overlooked. Its uniformly light color, relatively long head, very small eye, sharp and elongate snout, naked breast and belly, relatively small and numerous dermal scutes, numer- ous ribs, and few-pointed gill-rakers, separate it sharply from the common shovelnose. Its scarcity must doubtless explain its absence from our literature. According to Mr. Ashlock's estimate, about one in five hundred of the shovelnose sturgeons taken in the central Mississippi belongs to this new species, and 38 as the number of these sturgeons examined by all the ichthy- ologists of America taken together, doubtless falls far short of five hundred, it is not remarkable that it has hitherto been overlooked. Recognizing, as we are disposed to do, the generic criteria proposed for the scaphirhynchoids by Berg ('04), we regard this form as generically distinct from species hitherto described. Parascaphirhynchus, gen. nov. Snout broad, shovel-.shaped ; caudal peduncle long and flattened above, broader than deep, and completely covered by scutes. Breast and belly naked, sides sprinkled with small discoidal ossifications. Lips four-lobed ; spiracles and pseudo- branchs wanting ; gill-rakers fan-shaped, two- or three-pointed on the lower half of the arch ; ribs twenty or twenty-one ; air-bladder well developed, about 8 times in length of head and body. One species; known at present only from the Mississippi River. Parascaphirhynchus alhus, sp. nov. Head long, 2.9 to 3.2 in total length, and the body compar- atively short ; depth, 7.5 to 9 in length of head and body ; dis- tance from gill-cavity to front of dorsal 2.5 in total length. Color very light, the upper parts bluish gray in life, the lower parts of the sides and belly shading from very light gray to almost milky white. Scutes small (PI. VI.), sixteen to nineteen in the dorsal row, forty-one to forty-seven in the lateral, and ten to thirteen in the ventral. Spines of the dorsal and lateral scutes sharp, projecting strongly backward, and reaching to near the poste- rior border of the scute. Denticulated ossifications between the dorsal and lateral, and lateral and ventral rows of scutes diminishing in size and abundance from above downward. A few imperfect plates along the dorsal' row of scutes, extending as far forward as the backward reach of the pectorals, more numerous and larger backwards, and becoming continuous with 89 the dorsal covering of the caudal peduncle. Belly wholly naked in front of ventrals ; breast with a few bony points similar to those on the low^er part of the sides. The pectoral shields are long and narrow (PI. V.), the triangular, posterior part equal- ing in area the remainder of the shield. Rostrum long and narrow (PI. V.), 2.5 to 2.9 in length of head ; the eye very small, 8.3 to 10 in the interorbital space, which is 3.7 to 4.2 in the length of the head. Barbels doubly pectinated on the anterior edge, the posterior pectinations ob- solete or wanting, the inner barbels 1.7 to 2.9 in length of outer. Mouth large, 1.4 to 1.6 in the greatest width of the ros- trum. Papillae of the four clusters on the lower lip reduced to a few flattened scallops at the hinder edge of the lappet. Gill-membranes united to the isthmus and to each other in a deep angle (PI. V.), and continued backward to cover the anterior fourth of the pectoral shields. Operculum long and narrow, its depth contained more than twice in distance from posterior margin of cheek to posterior margin of gill-opening, and this distance about 8.5 times in length of head and body. Gill-rakers 10 or 11,+ 8, the two rows of each arch separated by a broad smooth surface (PI. VII.). Dorsal fin of 35 to 43 rays, the length of its base 11.8 to 12.8 in length of head and body; anal rays 20 to 23, ventral rays 28 to 26. Length of our seven specimens 19 to 43 inches, to base of caudal fin, the largest weighing 9.75 pounds. Mr. Ashlock has seen specimens 4.5 feet long, with an estimated weight of 16 pounds. Described from 9 specimens. The sexual differences are not known, all our specimens being males. The species is said by Mr. Ashlock to spawn between March and June, and to continue spawning sometimes as late as August. The testes were well developed in those taken about the middle of June. Although seen by us only from the Mississippi River at Grafton, this fish is said by Mr. Ashlock to be more abundant along the lower Missouri. Catches of sturgeon were seen by 40 him at West Alton, Mo., in which a fifth of the number were of this species. It is also said by him to occur, as a rule, in swifter water than the common shovelnose. The following table exhibits some of the more important differences observed in comparing our nine specimens of ParascapJiirhynchiis alhiis with twenty-one specimens of Scaphi- rhyncltus platorhynclmf< in the Laboratory collection. P.albus S. p/ator/iMic/uis Ribs 20 or 21 10 or 1 1 Ventral radials 9 7 Gill-rakers (points) 2 or 3 2- 5 (usually 4 or 5 Air-bladder in length head and body . . 8 5 Belly and breast naked fully armored Sides between scutes oss^catTons Depth lateral scutts in length head and body .... 28—32.5 19.8— 23.8 T- • • . U-. 1 o ^ , ?.?—8.3 (usuallyEye in interorbital space 8.3— 10 -' ^,^^ i-r ^ . ' J t^ -> less than 7) Inner barbel in outer 1.7—2.9 i.i— 1.4 Width mouth in width snout 1.4— 1.6 1.6— 1.9 Width head in length head 2.5—2.9 1.9—2.2 Length head in length head and body 2.9—3.2 3-5-~3-8 The first of the shovelnose sturgeons was described in 1820 by Rafinesque as Acipenser pJcdorhynelius, and was, in 1835, made by Heckel the type of a new genus distinguished from Acipenser by the absence of spiracles. The first of the Asiatic species was described by Kessler from the Suir-dar in 1872 as S. fedtschenkoi ; the second, S. kaufmanni, by Bogdanov in 1875; and the third in 1877 from the Amu-dar as S. hermanni by Kessler, who also discussed and figured Bogdanov's species. A fourth species was described by Nikolsky in 1900 as the type of a new genus, PseudoscapliirJiynchus. Berg ('04) unites the three preceding species under this genus, but does not recognize Nikolsky's species as distinct. The American and Asiatic species were first subjected to detailed anatomical analysis by Brutzer ('59) and Iwanzow ('87), the memoir of the latter being our fullest treatise on its subject. Zografl: wrote in 1887, and again in 1896, especially on the embryonal teeth of these and other cartilaginous ganoids- 41 The two genera above mentioned have recently been studied by Berg ('04). The following analytical table will serve to exhibit the re- lations of the three genera here recognized, the characters of the Asiatic genus being derived by us from the papers of Berg, Nikolsky, and Kessler. A. Caudal peduncle shortened and laterally compressed as in Acipenser, the rows of scutes not meeting above and be- low to form a complete armor ; mouth as in Acipense)', the lips two-lobed* and without clusters of papillae ; gill- rakers lance-shaped as in Acipenser ; air-bladder small or rudiraentaryf ; ribs numerous.}: Psei(dosc((pIi irIujHch ua Nikolsky. AA. Caudal peduncle lengthened, depressed, broader than deep, and completely armored ; lips four-lobed, each lip bearing four clusters of flattened tubercle-like lappets ; gill-rakers fan-shaped, two-, three-, four-, or five-pointed on the lower half of the arch. h. Piibs twenty or twenty-one ; gill-rakers two- or three- pointed ; belly and breast naked ; air-bladder 8 in length of head and body. Parascaphirhynchns, gen. nov. hh. Ribs ten or eleven ; gill-rakers two-, three-, four-, or five- pointed ; belly and breast wholly covered with subrhom- bic plates ; air-bladder 5 in length of head and body. Scaphii'hynchus Heckel. Issued May 15, 1905. *See Berg, Zool. Anz., XXVII., 22, 1904, p. 667; also Kessler's fiugres of P. kaiifmanni and hermamti, AraloCaspian Exped., IV., 1877, Fig. 25 and 26. tOne twenty-seventh of length of head and body in P. fedtschenkoi. JTwenty-four or twenty-five in P. fedtschenko BIBLIOGRAPHY. Berg-, L. S. '04. Zur Systematikder Acipenseriden. Zool. Anz., Bd. XXVII. , Nr. 22, pp. 665-667. Brandt, J. F. '69. Einig-e Worte uber die Europaische-Asiati^chen Stor-Arten. Melang. Biolog-., T. VII., pp. 110-116; Bull. Ac. Sc. St. Pe- tersb , T. XIV., pp. 171-175. Bridg-e, T. W. '96. The Mesial Fins of Ganoids and Teleosts. Jour. Linn. Soc. Lond., Vol. XXV., pp. 530-602, PI. XXXII-XXXIII. Brutzer, G. *'59. De Scaphirhyncho Rafinescii disquisitiones anatomicae. Dorpat, 1859. DaviJoff, M. V. '79. Beitrage zur vergleicbenden Anatomie der hinleren Glied- masse der Fische. Morph. Jahrb., Bd. V., pp. 450-520, Taf. XXVIIL—XXXI. Fitzinger, L., and Heckel, J. '41. Monographische Darstellung-der Gattung Acipenser. Ann. Wiener Mus. Naturgesch., Bd. II., pp. 263-.'^2d, Taf. XXV- XXX. Gray, J. E. '34. Characters of two new species of Acipenser. Proc. Zool. Soc. London, Vol. II., pp. 122-123. Greve, C. '96. Ueber die Lebensweise der central-asialischen Arten der Gattung Scaphir/iynchus. SB. Ges. Dorpat, Bd. XL, pp. 137- 144. Giinther, Albert. '73. Note on Scaphirhynchus Fedtschenkoi. Ann. Mag-. Nat. Hist., Ser. 4, Vol. XII., 1873, No. 70, p. 277. * Papers whose titles are starred have been seen by us in abstract only. 43 Meckel, J. '35. Scaphirhynchiis, eine neue Fischg-attuag" aus der Ordnung- der Chondropteryorier mit freien Kiemen. Ann. Wiener Mus. Naturgesch., Bd. I., pp. 71-78, Taf. VII. Iwanzow, N. '87. Scaphirhynchus. Eine vergleichend.-anatomische Beschreib- ung-. Bull. Soc. Imp. des Natural. Mosc, N. Sen, T. I., pp 1-41, Pi. I. and II. Kessler, K F. '72 On a remarkable Fish of the Family of Sturgeons discovered by M. A. P. Fedchenko in the River Suir-dar. Mem. Soc. d'Hist. Nat. Mosc, Vol. X , p. 26, PI. 12 (in Russian). Trans- lation, Ann. «& Mag-. Nat. Hist , Ser. 4, Vol. XII., 1873, No. 70, pp. 269-276. Redescribed and fig-ured in Fedchenko's Turkestan Journey, II, Pt. 6. p. 48, Pi. VI., Fig. 28, 29, and PI. VII., Fig. 30-35; Nachr. Ges. Mosc. XI., Ser. 5, 1874. *'77. The Aralo-Caspian Expedition. (IV. Fishes of the Aralo- Pontine Region.) 360 pp., 26 fig. Suppl to Trans. Petersb. Nat. Hist. Soc. (in Russian). Kirsch, P 11 , and Fordice, M. W. '89. A Review of the American Species of Sturgeons (Acipen. seridse). Proc. Acad Nat. Sci. Phila., 1889, pp. 245-257. Nikolsky, A. M. '00. Pseudoscaphirhynchus rossokowi, n. gen. et spec. Annuaire Mus. St. Petersb , T. V , pp. 257-259. Pelzam, E. * '83. Biologische Untersuchungen ueber Stor-artige Fische. SB. Naturf. Ges. Kasan, Beitrage No. 65. 17 pp. Rafinesque, C. S. '20. Ichthyologia Ohiensis, p. 80. Regan, C. T. '04. The Phylogeny of the Teleostomi. Ann. & Mag. Nat. Hist., Ser 7, Vol. XIIL, No. 77, pp. 329-349, Fig. 1-4, and PI. VII. Thacher, J. K. '77. Median and Paired Fins, a Contribution to the History of Vertebrate Limbs. Trans. Conn. Acad. Arts and Sci., Vol. III., pp. 281-310, PL XLIX.-LX. '77a. Ventral Fias of Ganoids. Trans. Conn. AcaJ. Arts and Sci., Vol. IV., pp. 233-242, PI. I. and II. 44 Westberg^, P. '99. Ueber die Fischg-altung- Scaphirhynchus. KB. Ver. Rig"a» Bd. XLII., pp. 159-160. Zograff, N. '87. Ueber die Zahne der Knorpel-Ganoiden. Biol. Centralbl., Bd. VII., Nr. 6, pp. 178-183. '87a. On some of the Affinities between G.iQoidei-Chondrostei and other Fishes. Nature, Vol. XXXVII. , p. 70. * '96. Note sur I'odontog-raphie des Gaooidei-Chondrostei. Ann. Sci. Nat. Ser. 8, T. I., pp. .197-219, PI. IV. and V.; Abstract, Congr. Zool. Leyden, pp. 320-322. VI. r^-^^z '7C^' ::':?Jv;. ^<«A:i>^>fe mivt '^^**ll<^^ CM '-0 5- N ~» VIL fl