01927nas a2200157 4500008004100000022001400041245006100055210006100116260001600177490000600193520147300199100001901672700001601691700002001707856004201727 2023 eng d a2517-484300aHistology of Convergent Probing Appendages in Mormyridae0 aHistology of Convergent Probing Appendages in Mormyridae cJan-01-20230 v53 a

Mormyridae is an early diverging family of Teleostean fishes that produce an electric field for navigation and communication using an electric organ. This clade has a diverse array of soft-tissue rostral appendages, such as the chin-swelling, the Schnauzenorgan, and the tubesnout combined with a Schnauzenorgan, that have evolved multiple times. Here we assess if macroscopically convergent, soft-tissue rostral appendages are also histologically convergent. Further, we investigate how the histology of these appendages can inform their function. We sampled independent gains of the chin-swelling and Schnauzenorgan to understand similarities and differences in their anatomies. We show that macroscopically convergent rostral appendages are also convergent at a histological level, and different types of rostral appendages share a similar anatomy; that said, minor differences likely relate to their specific functions. Based on a comparison of the skeletal muscle distribution and the differing attachment shapes of each appendage to the dentary, we conclude that the Schnauzenorgan is capable of a wider range of movements than the chin swelling. Furthermore, the anatomy suggests that these soft-tissue rostral appendages likely function as electrosensory foveas (i.e., an appendage that focuses a sensory system). Lastly, these histological data support the hypothesis that the chin swelling may be a precursor to the Schnauzenorgan.

1 aPeterson, Rose1 aEvans, A, J1 aHernandez, L, P uhttp://dx.doi.org/10.1093/iob/obad00100858nas a2200145 4500008004100000022001400041245009800055210006900153260001600222520037400238100001900612700002200631700001700653856004200670 2022 eng d a2687-794500aThe Complete Genome Sequences of 38 Species of Elephantfishes (Mormyridae, Osteoglossiformes)0 aComplete Genome Sequences of 38 Species of Elephantfishes Mormyr cNov-21-20223 a

We present the complete genome sequences of 38 species of elephantfishes from 20 genera. Illumina sequencing was performed on genetic material from single wild-caught individuals. The reads were assembled using a de novo method followed by a finishing step. The raw and assembled data is publicly available via Genbank.

1 aPeterson, Rose1 aSullivan, John, P1 aPirro, Stacy uhttp://dx.doi.org/10.56179/001c.5607703382nas a2200349 4500008004100000022001400041245018800055210006900243260002300312300001200335490000900347520225000356653003002606653001902636653001902655653001902674653001702693653001302710653001402723653002402737100002202761700002102783700001702804700001902821700002002840700002402860700003202884700002502916700002102941700002302962856004702985 2022 eng d a1313-298900aMitogenome recovered from a 19th Century holotype by shotgun sequencing supplies a generic name for an orphaned clade of African weakly electric fishes (Osteoglossomorpha, Mormyridae)0 aMitogenome recovered from a 19th Century holotype by shotgun seq bPensoft Publishers a163-1960 v11293 a

Heteromormyrus Steindachner, 1866, a genus of Mormyridae (Teleostei: Osteoglossomorpha), has been monotypic since the description of Heteromormyrus pauciradiatus (Steindacher, 1866) from a single specimen. No type locality other than “Angola” was given and almost no specimens have been subsequently identified to this species. In order to investigate the relationship of this taxon to fresh specimens collected in Angola and elsewhere, whole genome paired-end sequencing of DNA extracted from the holotype specimen of Heteromormyrus pauciradiatus was performed and a nearly complete mitogenome assembled from the sequences obtained. Comparison of cytochrome oxidase I and cytochrome b sequences from this mitogenome to sequences from recently collected material reveal that Heteromormyrus pauciradiatus is closely related to specimens identified as Hippopotamyrus ansorgii (Boulenger, 1905), Hippopotamyrus szaboi Kramer, van der Bank & Wink, 2004, Hippopotamyrus longilateralis Kramer & Swartz, 2010, as well as to several undescribed forms from subequatorial Africa collectively referred to in the literature as the “Hippopotamyrus ansorgii species complex” and colloquially known as “slender stonebashers.” Previous molecular phylogenetic work has shown that these species are not close relatives of Hippopotamyrus castor Pappenheim, 1906, the type species of genus Hippopotamyrus Pappenheim, 1906 from Cameroon, and are thus misclassified. Hippopotamyrus ansorgii species complex taxa and another species shown to have been misclassified, Paramormyrops tavernei (Poll, 1972), are placed in genus Heteromormyrus and one genetic lineage from the Kwanza and Lucala rivers of Angola are identified as conspecific Heteromormyrus pauciradiatus. Three additional new combinations and a synonymy in Mormyridae are introduced. The morphological characteristics and geographical distribution of the genus Heteromormyrus are reviewed. The electric organ discharges (EODs) of Heteromormyrus species are to be treated in a separate study.

10aAngolan freshwater fishes10aHeteromormyrus10aHippopotamyrus10ahistorical DNA10amitogenomics10amormyrid10amuseomics10aslender stonebasher1 aSullivan, John, P1 aHopkins, Carl, D1 aPirro, Stacy1 aPeterson, Rose1 aChakona, Albert1 aMutizwa, Tadiwa, I.1 aMukweze Mulelenu, Christian1 aAlqahtani, Fahad, H.1 aVreven, Emmanuel1 aDillman, Casey, B. uhttps://doi.org/10.3897/zookeys.1129.9028702485nas a2200157 4500008004100000022001400041245013800055210006900193260001600262520192500278100002302203700001902226700001902245700002102264856004202285 2022 eng d a2517-484300aConvergence is Only Skin Deep: Craniofacial Evolution in Electric Fishes from South America and Africa (Apteronotidae and Mormyridae)0 aConvergence is Only Skin Deep Craniofacial Evolution in Electric cJun-14-20223 a

Apteronotidae and Mormyridae are species-rich clades of weakly electric fishes from Neotropical and Afrotropical freshwaters, respectively, known for their high morphological disparity and often regarded as a classic example of convergent evolution. Here we use CT-imaging and 3D geometric morphometrics to quantify disparity in craniofacial morphologies, and to test the hypothesis of convergent skull-shape evolution in a phylogenetic context. For this study we examined 391 specimens representing 78 species of Apteronotidae and Mormyridae including 30 of 37 (81%) of all valid genera with the goal to sample most of the craniofacial disparity known in these clades. We found no overlap between Apteronotidae and Mormyridae in the skull-shape morphospace using PCA and a common landmark scheme, and therefore no instances of complete phenotypic convergence. Instead, we found multiple potential instances of incomplete convergence, and at least one parallel shift among electric fish clades. The greatest components of shape variance in both families are the same as observed for most vertebrate clades: heterocephaly (i.e., opposite changes in relative sizes of the snout and braincase regions of the skull), and heterorhynchy (i.e., dorsoventral changes in relative snout flexion and mouth position). Mormyrid species examined here exhibit less craniofacial disparity than do apteronotids, potentially due to constraints associated with a larger brain size, ecological constraints related to food-type availability. Patterns of craniofacial evolution in these two clades depict a complex story of phenotypic divergence and convergence in which certain superficial similarities of external morphology obscure deeper osteological and presumably developmental differences of skull form and function. Among apteronotid and mormyrid electric fishes, craniofacial convergence is only skin deep.

1 aFord, Kassandra, L1 aPeterson, Rose1 aBernt, Maxwell1 aAlbert, James, S uhttp://dx.doi.org/10.1093/iob/obac02203320nas a2200325 4500008004100000022002500041245015700066210006900223260001600292300001600308490000700324520229000331653001102621653003102632653001402663653001702677653002202694653001802716100001902734700002202753700002102775700002802796700002302824700001702847700002402864700002002888700002002908700002102928856004502949 2022 eng d a1063-5157, 1076-836X00aPhylogenomics of bonytongue fishes (Osteoglossomorpha) shed light on the craniofacial evolution and biogeography of the weakly electric clade Mormyridae0 aPhylogenomics of bonytongue fishes Osteoglossomorpha shed light  cJan-18-2022 a1032–10440 v713 a

Abstract Bonytongues (Osteoglossomorpha) constitute an ancient clade of teleost fishes distributed in freshwater habitats throughout the world. The group includes well-known species such as arowanas, featherbacks, pirarucus, and the weakly electric fishes in the family Mormyridae. Their disjunct distribution, extreme morphologies, and electrolocating capabilities (Gymnarchidae and Mormyridae) have attracted much scientific interest, but a comprehensive phylogenetic framework for comparative analysis is missing, especially for the species-rich family Mormyridae. Of particular interest are disparate craniofacial morphologies among mormyrids which might constitute an exceptional model system to study convergent evolution. We present a phylogenomic analysis based on 546 exons of 179 species (out of 260), 28 out of 29 genera, and all six families of extant bonytongues. Based on a recent reassessment of the fossil record of osteoglossomorphs, we inferred dates of divergence among trans-continental clades and the major groups. The estimated ages of divergence among extant taxa (e.g., Osteoglossomorpha, Osteoglossiformes, Mormyroidea) are older than previous reports, but most of the divergence dates obtained for clades on separate continents are too young to be explained by simple vicariance hypotheses. Biogeographic analysis of mormyrids indicates that their high species diversity in the Congo Basin is a consequence of range reductions of previously widespread ancestors and that the highest diversity of craniofacial morphologies among mormyrids originated in this basin. Special emphasis on a taxon-rich representation for mormyrids revealed pervasive misalignment between our phylogenomic results and mormyrid taxonomy due to repeated instances of convergence for extreme craniofacial morphologies. Estimation of ancestral phenotypes revealed contingent evolution of snout elongation and unique projections from the lower jaw to form the distinctive Schnauzenorgan. Synthesis of comparative analyses suggests that the remarkable craniofacial morphologies of mormyrids evolved convergently due to niche partitioning, likely enabled by interactions between their exclusive morphological and electrosensory adaptations.

10aAfrica10aAncestral State Estimation10aDiversity10aExon Capture10aFreshwater fishes10aPhylogenomics1 aPeterson, Rose1 aSullivan, John, P1 aHopkins, Carl, D1 aSantaquiteria, Aintzane1 aDillman, Casey, B.1 aPirro, Stacy1 aBetancur-R, Ricardo1 aArcila, Dahiana1 aHughes, Lily, C1 aOrtí, Guillermo uhttp://dx.doi.org/10.1093/sysbio/syac001