The pelvic girdle in extant gonorynchiformes (Teleostei: Otomorpha)

Volume 143, pages 141–150, (2024)
Ann-Katrin Koch & Timo Moritz

Abstract
Otophysi is one of the most important fish taxa of the world, as they make up for roughly 28% of all fish species and about two-thirds of all freshwater species worldwide. To understand their success and evolutionary history their sister-group, the Gonorynchiformes, take a key-position, e.g., for reconstructing morphological conditions in the latest common ancestors. Gonorynchiformes comprising only 40 species and have been often studied for that reason. Their pelvic girdle, however, got only little attention so far. Therefore, we studied this structure in extant gonorynchiforms and described the ontogeny in Kneria stappersii. In gonorynchiforms: (1) their basipterygium is principally flat (without dorsal or ventral projections) and placed in horizontal position, (2) has a ‘simple’ shape, i.e., it has only a single anterior process with small cartilaginous tips and becomes wider in its posterior part with a medial portion connecting to the basipterygium of the other side; (3) three radials and a pelvic splint are present, and (4) a prominent posterior process is missing. Although, the morphological situation is a lot similar as seen in clupeiforms and alepocephaliforms. Therefore, these characters have likely been present in the stem of Otomorpha, Ostariophysi, and Otophysi, but within the latter taxon eventually, a higher diversity of pelvic girdle morphology arose during evolution.

Two New Shellear Species (Gonorhynchiformes: Kneriidae), from the Luansa River (Upper Congo Basin): Hidden Diversity Revealed by Integrative Taxonomy

by Lewis Ngoy Kalumba ,Emmanuel Abwe, Frederic D. B. Schedel, Auguste Chocha Manda, Ulrich K. Schliewen andEmmanuel J. W. M. N. Vreven

Abstract
Abstract Two new Kneria species, K. luansaensis sp. nov. and K. maxi sp. nov., are described from the Luansa River, a left bank tributary of the lower Luapula in the Bangweulu–Mweru ecoregion, based on an integrative approach using morphological and COI barcoding evidence. While K. luansaensis sp. nov. occurs from the source of the Luansa further downstream to above the last of the three Sanshifolo Falls, K. maxi sp. nov. only occurs downstream of all these three major falls. In Kneria, males of about ≥ 33 mm LS have an opercular and a postopercular organ. The number of lamellae on the latter seems to contain some alpha-taxonomic information, although this requires further study as allometric changes occur at about ≤ 45 mm LS. Additional external morphological characters differ between sexes, i.e., the (i) pectoral fin width (wider in males than females), (ii) dorsal fin height (longer in males than females), and (iii) length of the longest ray of the lower caudal fin lobe (longer in males than females). Agriculture, fishing with ichthyotoxines, and logging are the most pressing threats on the Luansa and thus to both the new species. Their discovery in one of the rivers of the Kundelungu Plateau and its surroundings located outside the present-day boundaries of the Kundelungu National Park highlights the need for a refined and improved protection strategy for this freshwater key biodiversity area.

Keywords: COI barcoding; Kneria luansaensis sp. nov.; K. maxi sp. nov.; kundelungu national park; kundelungu plateau; morphological approach; opercular/postopercular organ; protection; sexual dimorphism; waterfalls

2023 Abwe

Checklist of the Fishes of the Kundelungu National Park (Upper Congo Basin, DR Congo): Species Diversity and Endemicity of a Poorly Known Ichthyofauna

Abstract
The fish diversity of the Kundelungu National Park (KNP), one of the seven national parks of the Democratic Republic of the Congo, has never been thoroughly studied. This first checklist is presented based on a literature compilation and the study of historical (1939–1969) and recent collections (2012–2017). A total of 96 taxa are reported, including 64 native described species, one introduced species (Poecilia reticulata), 13 new species that await formal description and 18 possibly new species that require further investigation to verify their status. These taxa represent 39 genera and 17 families from the KNP including its Buffer Zone (BZ). Only six taxa, including five endemics, are known from the Core Zone on the Kundelungu Plateau (1300–1700 m alt.). At lower altitudes (800–1100 m), in the Annex Zone, 71 taxa, including 17 endemics, were found. Finally, 50 taxa, including 13 endemics and one introduced species, are known from its BZ. The fish fauna of the KNP is threatened by overfishing, destructive fishing practices, and habitat degradation due to mining pollution, and deforestation for agriculture on the river banks. The present study provides the much needed baseline data for the protection and conservation planning of this fish fauna, for which conservation suggestions are formulated. Keywords: anthropogenic impacts; Endemism; Kundelungu Plateau; new species

2022 Mutambala

A new Parakneria Poll 1965 (Gonorhynchiformes: Kneriidae), ‘Mikinkidi’ from the Upper Lufira Basin (Upper Congo: DRC): Evidence from a morphologic and DNA barcoding integrative approach

Pacifique Kiwele Mutambala, Emmanuel Abwe, Frederic D. B. Schedel, Auguste Chocha Manda, Ulrich K. Schliewen, Emmanuel J. W. M. N. Vreven
Abstract
A new species, Parakneria alytogrammus, is described from the main stream of the Upper Lufira River. This species is easily distinguished from its congeners from the Congo Basin by its unique colouration, consisting of a low number of transversal bands on each of the caudal‐fin lobes, 2 (vs. 3–5) and the presence of an uninterrupted lateral mid‐longitudinal black band in fresh and preserved specimens (vs. absent). In addition, the new species differs from its Upper Lualaba congeners by the narrow width of its pectoral‐fin base, 4.8–5.6% LS [vs. wider, 8.2–10.1% for P. lufirae, 8.6% LS for P. damasi (holotype), and 7.6–7.9% LS for P. thysi]. Finally, it differs from the only species currently known from the Luapula‐Mweru system, P. malaissei, by having a short post‐dorsal distance, 36.4–36.6% LS (vs. longer, 38.6–41.1% LS) and a short post‐pelvic distance of 40.0–40.6% LS (vs. longer, 41.4–44.1% LS). Mitochondrial DNA‐haplotypes of P. alytogrammus sp. nov. form a clade, which is sister to the P. thysi clade, and from which it diverges by a genetic (Kimura 2‐parameter and uncorrected p) distance of 0.7% in the COI‐barcoding locus. The Upper Lufira, one of the sub‐basins of the Upper Congo Basin, remains poorly explored relative to its fish fauna. In contrast, the region is well explored with regard to its mineral wealth. Unfortunately, mining exploitation is carried out in the region without proper concern for the environment. Thus, the discovery of this new species for science calls for increased protection and aquatic biodiversity explo

2013 Davis

The first fossil shellear and its implications for the evolution and divergence of the Kneriidae

Matthew P. DAVIS, Gloria ARRATIA and Thomas M. KAISER

Abstract
A new genus and species of shellear (Gonorynchiformes: Kneriidae), †Mahengichthys singidaensis, is described from the Eocene Mahenge deposits in Tanzania, Africa. This work represents the first record of a fossil kneriid gonorynchiform fish. Previously, all gonorynchiform fossils have been attributed to either the families Chanidae or Gonorynchidae, with some taxa incertae sedis. We explore the phylogenetic position of †Mahengichthys singidaensis within the gonorynchiforms, utilizing parsimony and maximum likelihood methodologies that incorporate both morphological and molecular data. Our results indicate that †Mahengichthys singidaensis is a kneriid gonorynchiform within the tribe Kneriini, which includes the extant genera Kneria and Parakneria. This phylogenetic work provides a framework for estimating the divergence times of the Kneriidae for the first time using Bayesian methodology with calibrations that include information regarding extinct kneriids. We infer that the exclusively freshwater family Kneriidae most likely diverged and diversified during the Cretaceous to Paleogene in Sub-Saharan Africa, following the continent’s separation from South America.

2010 Grande

Gonorynchiformes and Ostariophysan Relationships

Chapter 01

Reassessment and Comparative Morphology of the Gonorynchiform Head Skeleton

Chapter 02

Morphological Analysis of the Gonorynchiform Postcranial Skeleton

Chapter 03

Early Ossification and Development of the Cranium and Paired Girdles of Chanos chanos (Teleostei, Gonorynchiformes)

Chapter 04

A Review of the Cranial and Pectoral Musculature of Gonorynchiform Fishes, with Comments on Their Functional Morphology and a Comparison with Other Otocephalans

Chapter 05

The Epibranchial Organ and Its Anatomical Environment in the Gonorynchiformes, with Functional Discussions