49 Specimen. She Did Not Misidentify One of the Specimens of Atya Scabra She Reported from St. Paul's River Near Mt. Coffee
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NUMBER 364 49 specimen. She did not misidentify one of the tion of the shrimp and stated that this species is specimens of Atya scabra she reported from St. thought to be confined to rocky sections of the Paul's River near Mt. Coffee, Liberia (see "Dis- river (Volta). tribution" of A. scabra herein). She erred, however, In his review of the caridean Crustacea of in considering specimens of A. qfricana to be con- tropical West Africa, Holthuis (1951) provided a specific with A. scabra in synonymizing A. gabonen- nearly complete synonomy for the species and sis with the latter, listing the Orinoco and "Ga- listed all of the known locality records, expressing bun" as localities for A. scabra. Thompson (1901) doubt, however, of the validity of the reported reported the presence of Atya gabonensis among the occurrence of the species in the Orinoco River, Crustacea "contained in the Museum of Univer- and erring in treating Rathbun's (1900), and sity College, Dundee," but noted the absence of perhaps Johnston's (1906), records for A. scabra in locality data. Liberia as those of A. gabonensis. Monod (1967) In recording the specimens of atyids in the cited the range of this shrimp as extending from Museum d'Histoire Naturelle (Paris), Bouvier Senegal to Gabon; his illustrations were taken (1904) stated that this shrimp is the most beau- from Bouvier (1925) and Irvine (1947). Gordon tiful and largest species belonging to the genus (1967) included no information concerning this Atya. He listed specimens from three localities (see shrimp. Reed (1967) reported its presence in most "Distribution and Specimens Examined"). The parts of northern Nigeria but noted that it is not following year (1905) he elaborated upon infor- common; it inhabits rocky areas of the "main mation offered in 1904, grouped A. gabonensis with river" and its tributaries. Yaro (1967) recorded the advanced members of the genus, and pre- the common names in several of the local dialects. sented illustrations of the rostrum and cephalo- Motwani and Kanwai (1970) reported the oc- lateral region of the carapace. In his monograph currence of large numbers of Atya gabonensis in the of the family Atyidae, Bouvier (1925) first ques- coffer-dammed right channel of the Niger River tioned the reported source of Koelbel's specimens, on 4 and 5 August 1966. Gill nets ensnared them stating that "POrenoque, ce qui tient peut etre a at depths as great as 11.4 m. Rutherford (1971) une fausse indication de provenance" (p. 319). added no new information other than his failure Following a detailed description and a presenta- to find members of the species along the Cape tion of the same figures published in 1904, he Coast of Ghana. Lemasson (1973), noting that summarized the range, restated the sizes (45 to this shrimp attains a total length of 12.4 cm, 124 mm) of the specimens available to him, and believed that it might lend itself to commercial discussed the relationships, stating that the most cultivation. Monod (1977) reported the range of highly evolved stock of the genus "a produit en A. gabonensis to include the coastal streams of West Afrique occidentale et en Amerique VA. gabonensis Africa and the islands of Fernando Poo and Sao et dans la region de l'isthme americain VA. crassa Tome; also he suggested that the distribution of qui represente avec l'espece precedente le point the species may be associated with rocky sub- terminal" (p. 357). strates. Monod (1928 and 1967) listed this shrimp as Powell (1979) noted that A. gabonensis occurred being fished in Cameroon and later (1933) re- in company with Potamalpheops haugi (Coutiere, ported it from the "Yabassi riv. Wouri," Came- 1906) in "whitewater mollusc rivers" (p. 116) of roon. In updating our knowledge of the crusta- the Niger Basin in Nigeria. Juveniles were found cean fauna of West Africa, Monod (1933) pre- "in the Nun branch of the Niger near Kaiama sented a new locality record for A. gabonensis and (about 95 km inland and 15 km upstream from questioned its occurrence in the Orinoco. Oliveira the extreme dry-season tidal-limit) ..." (p. 134). (1945) added no new data. Another locality was He pointed out that the locality Bouvier cited by Irvine (1947) who provided an illustra- (1925:319) cited on the Ogooue River lies about 50 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY 125 air-km from the coast. The similarity in body subconical and directed almost ventrally. Telson form of migrating juveniles of A. gabonensis and of 1.2 to 1.4 times as long as broad and bearing individuals of P. haugi of equal size render them paired arched dorsal rows of 4 or 5 spines. Anten- "difficult to separate with the naked eye" (p. nular peduncle with dorsal surface of proximal 136). Like P. haugi, according to Powell (p. 137), article bearing 1 to 6 spinules proximal to distal A. gabonensis "is perhaps restricted to relatively row; penultimate article 1.4 to 1.5 times as long hard waters," and he implied that it is present in as wide and bearing scattered sclerotized spinules the Osse watershed. Holthuis (1980) summarized in lateral half of dorsal surface. Coxae of third our knowledge of this shrimp, providing FAO and fourth pereiopods lacking prominent spine (Food and Agriculture Organization of the anterolaterally. Third pereiopod with merus United Nations) names, local names, geographi- somewhat flattened ventrally, about 2.5 times as cal and habitat distribution, and maximum size long as high; ventromesial surface parallel to that (total length: 124 mm for males and 92 mm for of corresponding podomere of other third pereio- females). References to its importance in fisheries pod, and lateral surface bearing irregular rows of are also included. Hobbs (1980:111) reported the heavy corneous tubercles with flattened, often presence of this species in Rio Piaui, Brazil. frayed, scalelike extremities; propodus 1.6 to 1.9 PUBLISHED ILLUSTRATIONS.—The first and best times as long as broad; extensor surface studded illustrations of Atya gabonensis are those of Koelbel with stalked corneous tubercles similar to those (1884) and include a beautifully executed lateral on merus and with very few widely spaced ones view of the entire body and appendages along on flexor surface, most tubercles on latter surface with a ventral view of the third pereiopod, lateral flanked distally by clusters of plumose setae; dac- view of the first pereiopod, and a posterior view tyl at least slightly movable, its flexor surface of each of the gnathal appendages. Bouvier (1905) bearing 1 to several tubercles in cluster just prox- provided a dorsal view of the rostrum, and the imal to corneous tip. rostral, orbital, and pterygostomian regions of the MALE (Volta River at Kpong Rapids, carapace were presented in lateral aspect. The Ghana).—Rostrum (Figure 20a,d) with margins latter figures were used by Bouvier (1925) in his somewhat tapering, but thickened and appearing monograph. The most recent illustration is that concave laterally, to base of acumen where pro- of Irvine (1947), a lateral view of the entire animal duced in spines reaching slightly beyond mid- that is much less detailed than Koelbel's figure 1 length of proximal podomere of antennule; apex on plate 3. Bouvier's figure has been reproduced of acumen overlying midlength of penultimate by Monod (1967) and Reed (1967). podomere of antennule; dorsal median carina, DIAGNOSIS.—Cephalic region of carapace although prominent, dipping below level of lat- strongly sculptured, but spines limited to anten- eral carinae posterior to acumen and reaching nal, pterygostomian, and occasional ventral and apex of latter; ventral carina poorly developed, often lateral rostral; pterygostomian spine rather ventral surface of rostrum grooved posteriorly, weak. Rostrum with margins suddenly con- receiving ocellar beak which strongly produced tracted, forming distinct angle anterior to orbit, anteriorly, ending in acute apex almost reaching angle often produced anteriorly; dorsal surface level of tip of stylocerite. Antennal and pterygos- without row of strong spines but with low median tomian spines moderately strong and acute, no carina. Ventral margin of abdominal pleura lack- spines present between them. Surface of carapace ing sclerotized spinules. Sternum of fifth abdom- densely punctate and rather ornate, marked by inal segment with median tubercle produced in strong ridges; submarginal punctations along curved hornlike projection usually overreaching ventral edge of carapace bearing conspicuous midlength of sixth sternite when abdomen flexed. setae. Sternum of sixth abdominal segment approxi- Pleura of first 3 abdominal segments (Figure mately one-half as long as wide. Preanal carina 20i) with rounded posteroventral extremities, cor- NUMBER 364 51 FIGURE 20.—Atya gabontnsis (all from male from Kpong rapids of Volta River, Ghana, except A from Rio Piaui, Brazil): a, dorsal view of cephalic region; b, mesial view of appendices masculina and interna; c, lateral view of preanal carina; d, lateral view of cephalic region; t, flexor surface of distal part of fourth pereiopod; /, lateral view of distal part of third pereiopod; gji, flexor surface of distal part of third pereiopod; i, lateral view of second through fifth abdominal pleura; j, dorsal view of telson; k, dorsal view of antennular peduncle; /, flexor surface of distal part of fifth pereiopod; m, lateral view of third pereiopod; n, ventral view of basal podomeres of right third pereiopod. (Scales marked in 1 mm increments.) 52 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY responding parts of fourth and fifth segments antennular peduncle, second reaching base of rounded to subangular but not produced. All distal fourth of fingers of first pereiopod; terminal pleura lacking corneous spinules on ventral mar- brush of setae of both appendages lacking scrap- gin but fifth with conspicuous row of plumose ing denticles.