Browsing by Author "Stiassny, Melanie L. J."
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ItemCongochromis, a new cichlid genus (Teleostei, Cichlidae) from Central Africa, with the description of a new species from the upper Congo River, Democratic Republic of Congo ; American Museum novitates, no. 3576(New York, NY : American Museum of Natural History, 2007) Stiassny, Melanie L. J.; Schliewen, Ulrich.Congochromis, a new cichlid genus, is described on the basis of a suite of anatomical features of the cephalic laterosensory system, infraorbital series, oral dentition, and squamation. As recognized herein, Congochromis comprises three species formerly included in the genus Nanochromis (N. squamiceps, N. dimidiatus, and N. sabinae) and a new species from the vicinity of Kisangani (Stanleyville) on the upper Congo River. Diagnostic features for Congochromis and Nanochromis s.str. are provided. Congochromis pugnatus, n.sp. is diagnosed by the possession of a distinctive pattern of hypural fusion, a strongly inclined lower jaw, and an expanded cheek musculature. ItemDescription of a new species of Rheocles (Atherinomorpha, Bedotiidae) from the Nosivolo tributary, Mangoro River, eastern Malagasy Republic. American Museum novitates ; no. 3031(New York, N.Y. : American Museum of Natural History, 1992) Stiassny, Melanie L. J.; Reinthal, Peter. ItemDescription of two new Labeo (Labeoninae; Cyprinidae) endemic to the Lulua River in the Democratic Republic of Congo (Kasai ecoregion) : a hotspot of fish diversity in the Congo basin (American Museum novitates, no. 3999)(American Museum of Natural History., 2023-05-18) Liyandja, Tobit L. D.; Stiassny, Melanie L. J.Labeo mbimbii, n. sp., and Labeo manasseeae, n. sp., two small-bodied Labeo species, are described from the lower and middle reaches of the Lulua River (Kasai ecoregion, Congo basin) in the Democratic Republic of Congo. The two new species are members of the L. forskalii species group and are genetically distinct from all other species of that clade. Morphologically they can be distinguished from central African L. forskalii group congeners except L. dhonti, L. lukulae, L. luluae, L. parvus, L. quadribarbis, and L. simpsoni in the possession of 29 or fewer (vs. 30 or more) vertebrae and from those congeners by a wider interpectoral, among other features. The two new species are endemic to the Lulua River and, although overlapping in geographical range and most meristic and morphometric measures, are readily differentiated by differing numbers of fully developed supraneural bones, predorsal vertebrae, snout morphology, and additional osteological features. The description of these two species brings the total of Labeo species endemic to the Lulua basin to three. The third endemic species, L. luluae, was previously known only from the juvenile holotype, but numerous additional specimens have now been identified. The cooccurrence of 14 Labeo species in the Lulua River, three of which are endemic, highlights this system as a hotspot of Labeo diversity in the Congo basin and across the continent. ItemEgg attachment systems in the family Cichlidae (Perciformes, Labroidei) : with some comments on their significance for phylogenetic studies. American Museum novitates ; no. 3058(New York, N.Y. : American Museum of Natural History, 1993) Stiassny, Melanie L. J.; Mezey, Jason G. ItemA new small barb (Cyprininae, Smiliogastrini) from the Louesse, Lekoumou (upper Niari Basin), and Djoulou (upper Ogowe Basin) rivers in the Republic of Congo, west-central Africa. (American Museum novitates, no. 3917)(American Museum of Natural History., 2018-12-26) Mamonekene, Victor.; Ibala Zamba, Armel.; Stiassny, Melanie L. J.A new species of smiliogastrin cyprinid is described from the Louesse, Lekoumou (upper Niari basin), and Djoulou (upper Ogowe basin) rivers in the Republic of Congo, west-central Africa. The new species is readily distinguished from congeners by the presence of a flexible, weakly ossified and smooth bordered last unbranched dorsal-fin ray, well-developed barbels, and a straight and complete lateral line in combination with a characteristic pigmentation patterning consisting of a distinctive, rounded black spot at the base of and extending over the first rays of the anal fin and a prominent, darkly pigmented blotch over the base of the anterior dorsal-fin rays. A combination of morphological features and pigmentation patterning that appears to be unique among Enteromius. The new species is widespread throughout the Louesse-Djoulou region, and the fact that such a seemingly common species has gone undetected until now serves to underscore how poorly known this region of the Republic of Congo remains. ItemA new small barb (Cyprininae, Smiliogastrini) from the N'sele and Mayi Ndombe rivers in the lower reaches of the middle Congo basin (Democratic Republic of Congo, Central Africa). (American Museum novitates, no. 3848)(American Museum of Natural History., 2016-02-04) Stiassny, Melanie L. J.; Liyandja, Tobit L. D.; Monsembula Iyaba, Raoul J. C.A new species of smiliogastrin cyprinid is described from tributaries of the middle Congo River in the Democratic Republic of Congo. Restriction of the genus name, Barbus, to certain large-bodied, (polyploid) barbins, and current uncertainty regarding phylogenetic relationships among the numerous small-bodied African (diploid) barbs, renders generic assignment for the new species problematical. Pending the results of ongoing systematic analyses, and to reduce short-term nomenclatural instability, the new species is described here as a species of "Barbus." "Barbus" validus, new species, is readily distinguished from all other small-bodied African barbs by the combined possession of scales in midlateral series that are not enlarged relative to those along the impinging rows above and below; well-developed barbels, with the maxillary pair extending beyond the level of mideye, and the mandibular pair reaching the level of midopercle; the presence of numerous conical tubercles over the snout, cheek, and dorsum of head; a small circular occipital fontanel located medially at the parietal suture; well-developed gill rakers, with 8 or 9 on the hypo- and ceratobranchial elements of the first arch; a last unbranched dorsal-fin ray that is weakly ossified and lacking serrations along the posterior border; and a dorsal fin that is creamy white proximally and with the distal half to two thirds darkly pigmented. ItemA new species of air-breathing catfish (Clariidae: Clarias) from Salonga National Park, Democratic Republic of the Congo (American Museum novitates, no. 3990)(American Museum of Natural History., 2022-08-30) Bernt, Maxwell J.; Stiassny, Melanie L. J.A new species of air-breathing catfish, Clarias monsembulai, is described from Congo River tributaries within and bordering the Salonga National Park (Democratic Republic of the Congo). The new taxon is recognized by its exceptionally long, white barbels, which lend a superficial resemblance to Clarias buthupogon, from which it differs in characters of the cleithrum and pigmentation patterning. We suggest placement of this species into the subgenus Clarioides but note the current dearth of morphological data to unite members of this group. We additionally discuss the validity of the subspecies Clarias angolensis macronema. ItemNotes on the anatomy and relationships of the bedotiid fishes of Madagascar : with a taxonomic revision of the genus Rheocles (Atherinomorpha, Bedotiidae). American Museum novitates ; ; no. 2979.(New York, N.Y. : American Museum of Natural History, 1990) Stiassny, Melanie L. J. ItemPhylogenetics of Teleogramma, a riverine clade of African cichlid fishes, with a description of the deepwater molluskivore--Teleogramma obamaorum--from the lower reaches of the middle Congo River. (American Museum novitates, no. 3831)(American Museum of Natural History., 2015-04-21) Stiassny, Melanie L. J.; Alter, S. Elizabeth.The lower Congo River and nearby habitats harbor numerous endemic lineages of cichlid fishes, including some with highly specialized morphologies. Based on morphological and molecular data, we herein describe a new species of Teleogramma, a member of the chromidotilapiine clade found on rocky outcrops in the lower reaches of the middle Congo River. The new species, T. obamaorum, is distinguished from congeners by numerous morphological and ecological attributes, including the lack of dorsoventral head and body depression, absence of sexual dichromatism, and features of laterosensory anatomy, pharyngeal and gut morphology, and dietary preference. Phylogenetic analyses of two nuclear and two mitochondrial loci using Bayesian and maximum-likelihood inference lend strong support for the taxonomic validity of T. obamaorum and provide preliminary estimates of species relationships within the genus. The discovery of a new, ecomorphologically distinctive cichlid species in the Congo River suggests that additional research focus on riverine clades has the potential to greatly contribute to our understanding of evolutionary dynamics in this hyperdiverse group of teleost fishes. ItemPhylogeny and taxonomic revision of the endemic Malagasy genus Ptychochromis (Teleostei, Cichlidae), with the description of five new species and a diagnosis for Katria, new genus ; American Museum novitates, no. 3535(New York, NY : American Museum of Natural History, 2006) Stiassny, Melanie L. J.; Sparks, John S.The Malagasy cichlid genus Ptychochromis is revised and five new species are described, one of which is presumed to be extinct. The three valid nominal species, P. oligacanthus, P. grandidieri, and P. inornatus, are redescribed with diagnoses provided for each. A phylogeny of ptychochromin cichlids, derived from the simultaneous analysis of morphological features and nucleotide characters from a combination of mitochondrial and nuclear genes is presented. Ptychochromis is diagnosed by a suite of derived features of the pharynx, infraorbital series, and palatine morphology. In addition, the sister taxon to Ptychochromis, Ptychochromoides katria, is removed from Ptychochromoides and placed in its own genus, Katria, which is described herein as new. Katria is diagnosed by a unique pigmentation pattern, the absence of paired anterior gas bladder chambers that approach the neurocranium, an elevated vertebral count, and a slender caudal peduncle. An unnamed clade comprising Ptychochromis and Katria is diagnosed by a suite of derived features of the pharynx, sensory canal system, supraneural patterning, and palatine morphology. ItemRehabilitation of the Malagasy endemic Kuhlia sauvagii Regan, 1913 (Teleostei, Perciformes), with the designation of a neotype for Centropomus rupestris Lacépède, 1802 ; American Museum novitates, no. 3561(New York, NY : American Museum of Natural History, 2007) Loiselle, Paul V.; Stiassny, Melanie L. J.Based on differences in adult coloration, behavior, and morphometric and meristic features, the endemic Malagasy kuhlid Kuhlia sauvagii Regan, 1913, is resurrected from synonymy with the Indo-Pacific Kuhlia rupestris (Lacépède, 1802). Both species are redescribed, and a summary of their distribution, natural history, and conservation status on Madagascar is provided. No type specimens for Centropomus rupestris Lacépède, 1802 (type locality, Réunion), are known, and considerable confusion persists in the literature regarding the taxonomic composition and limits of this purportedly widespread species. We designate as neotype for Centropomus rupestris a syntype of Dules fuscus Cuvier in Cuvier and Valenciennes, 1829, thereby unambiguously relating this taxon to material collected from the type locality of Lacépède's Centropomus rupestris, the island of Réunion in the western Indian Ocean. ItemReport on a small collection of fishes from the Wologizi Mountains of Liberia, West Africa : with a description of two new species of Barbus (Ostariophysi, Cyprinidae). American Museum novitates ; no. 3015(New York, N.Y. : American Museum of Natural History, 1991) Stiassny, Melanie L. J. ItemRevision of the Congo River Lamprologus Schilthuis, 1891 (Teleostei, Cichlidae), with descriptions of two new species. American Museum novitates ; no. 3451(New York, NY : American Museum of Natural History, 2004) Schelly, Robert C.; Stiassny, Melanie L. J.The Congo River Lamprologus are revised and two new species are described. Lamprologus teugelsi, n.sp., from Malebo Pool and the lower Congo River rapids, and L. tigripictilis, n.sp., from the lower Congo River rapids, are readily distinguished from the remaining Congo River Lamprologus based on counts, measurements, osteology, and color pattern. Monophyly of the Congo River Lamprologus species is tentatively accepted and a key to the group is provided. All available collection localities for re-identified Lamprologus material from the Congo River are plotted for each species. Maps of collection localities reveal large distributional voids, suggesting that Congo River lamprologine diversity remains incompletely sampled. ItemSystematic review and cranial osteology of Petersius with redescription of P. conserialis (Teleostei: Alestidae) from the Rufiji and Ruvu rivers of Tanzania (American Museum novitates, no. 3992)(American Museum of Natural History., 2022-11-15) Melo, Bruno F. 1987-; Stiassny, Melanie L. J.We review the systematics of the monotypic alestid genus Petersius and provide a taxonomic redescription of P. conserialis from eastern Tanzania. Morphological investigation includes direct observation and examination of radiographed and μCT-scanned data from type and non-type specimens. We delimit the taxon’s geographic distribution along the lowland regions of the Rufiji and Ruvu river basins in Tanzania and provide information on ecology, sexual dimorphism, and ontogenetic variation. Petersius is herein diagnosed by the possession of a unique cuspidation patterning of the inner-row premaxillary dentition and a distinctively shaped anterodorsal margin of the supraoccipital crest. It shares with some species of Phenacogrammusa sigmoid-shaped process on the dorsal margin of the second infraorbital, a feature lacking in other alestid taxa. Additional features of potential utility for ongoing investigation of relationships among alestid genera include the possession of contralateral premaxillae separated by the anteromedial process of the mesethmoid and without interdigitations connecting the medial surfaces of the premaxillae; four, occasionally five or six, small outer-row premaxillary teeth implanted alternately with those of the inner row; a dentary lacking a pair of conical inner-row teeth proximal to the symphysis; a dorsal posttemporal fossa that is smaller than the ventral fossa; a median third posttemporal fossa located entirely within the epioccipital; a truncate dorsomedial cranial fontanel; and a complete circumorbital series forming an uninterrupted ring around the orbit in adult specimens. ItemTwo new Phenacogrammus (Characoidei; Alestidae) from the Ndzaa River (Mfimi-Lukenie basin) of central Africa, Democratic Republic of Congo (American Museum novitates, no. 3980)(American Museum of Natural History., 2021-11-03) Stiassny, Melanie L. J.; Alter, S. Elizabeth; Monsembula Iyaba, Raoul J. C.; Liyandja, Tobit L. D.Two new Phenacogrammus are described from the Ndzaa River, a small left-bank tributary of the Mfimi-Lukenie River in the central Congo basin. They share with P. deheyni, a congener endemic to the Cuvette Centrale to the north, a prominent anterior expansion of the first pleural rib; a feature interpreted here as a synapomorphy diagnostic for this species assemblage. The two new species are readily differentiated from P. deheyni based on differences in pigmentation patterning, a lower number of scales in longitudinal series (26–28 vs. 29–33) and a longer head length (m. 24.9% SL vs. 21.7 and 23.2% SL). Phenacogrammus flexus, new species, is distinguished from all congeners in the possession of 6 (vs. 7) supraneural bones, and a characteristic zigzag pattern of black pigmentation along and below the midline extending from the posterior border of the opercle to the base of the caudal peduncle. While no unambiguous morphological autapomorphies have been located to diagnose P. concolor, new species, it is nonetheless readily distinguished from all congeners, except P. deheyni and P. flexus, in the possession of a prominent anterior expansion of the first pleural rib. It differs from both P. deheyni and P. flexus in the absence of a dominant pigmentation patterning over the flanks and caudal peduncle. Additionally, it differs from P. flexus in a shallower body depth (m. 24.9% vs. 27.0% SL) and in the possession of 7 (vs. 6) supraneurals. The three species exhibit extensive divergence in mt-COI sequence (P. flexus vs. P. concolor 10.2%–11%; P. flexus vs deheyni 12.9%–13.5%; P. concolor vs. deheyni 11.3%–12.9%). Furthermore, analysis of shape variation utilizing geometric morphometrics indicates that each species differs significantly in body shape. ItemTylochromis : relationships and the phylogenetic status of the African Cichlidae. American Museum novitates ; no. 2993(New York, N.Y. : American Museum of Natural History, 1990) Stiassny, Melanie L. J. ItemAn unexpected new Poropanchax (Cyprinodontiformes, Procatopodidae) from the Kongo Central Province, Democratic Republic of Congo. (American Museum novitates, no. 3941)(American Museum of Natural History., 2019-10-10) Van der Zee, Jouke R.; Bernotas, Kimberly.; Bragança, Pedro H. N.; Stiassny, Melanie L. J.A new procatopodid, assigned to the genus Poropanchax, is described from a wetland habitat located adjacent to the Inga Falls in Lower Congo. Poropanchax pepo, new species, is distinguished from all congeners by a combination of characters including a higher D/A ratio, rounded anal and dorsal fins, a humeral blotch in males, and the absence of a sharp ventral process on the basipterygium. The finding of a Poropanchax species in Lower Congo was unexpected, since the closest known congeneric population is located in northwestern Gabon, some 700 kilometers to the north. As recognized herein the genus Poropanchax is a clade comprised of five species geographically restricted to humid coastal regions of west and west-central Africa.