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opencc-zeroDec 2008View details →

Data from: Data set incongruence and correlated character evolution: an example of functional convergence in the hind-limbs of stifftail diving ducks

The unwitting inclusion of convergent characters in phylogenetic estimates poses a serious problem for efforts to recover phylogeny. Convergence is not inscrutable, however, particularly when one group of characters tracks phylogeny and another set tracks adaptive history. In such cases, convergent characters may be correlated with one or a few functional anatomical units and readily identifiable using comparative methods. Stifftail ducks (Oxyurinae) offer one such opportunity to study correlated character evolution and function in the context of phylogenetic reconstruction. Morphological analyses place stifftail ducks as part of a large clade of diving ducks that includes the sea ducks (Mergini), Hymenolaimus, Merganetta, and Tachyeres, and possibly the pochards (Aythyini). Molecular analyses, on the other hand, place stifftails far from other diving ducks and suggest, moreover, that stifftails are polyphyletic. Mitochondrial cytochrome b gene sequences of eight stifftail species traditionally supposed to form a clade were compared with each other and with sequences from 50 other anseriform and galliform species. Stifftail ducks are not the sister group of sea ducks, but lie outside the typical ducks (Anatinae). Of the four traditional stifftail genera, monophyly of Oxyura and its sister group relationship with Nomonyx are strongly supported. Heteronetta probably is the sister group of that clade, but support is weak. Biziura is not a true stifftail. Within Oxyura, Old World species (O. australis, O. leucocephala, O. maccoa) appear to form a clade, with New World species (O. jamaicensis, O. vittata) branching basally. Incongruence between molecules and morphology is interpreted to be the result of adaptive specialization and functional convergence in the hind limbs of Biziura and true stifftails. When morphological characters are divided into classes, only hind-limb characters are significantly in conflict with the molecular tree. Null models of synonomous and nonsynonomous substitution based on patterns of codon-degeneracy and chemical dissimilarity, likewise, indicate that the nucleotide and amino acid changes postulated by the molecular tree are more plausible than those postulated by the morphological tree. These findings teach general lessons about the utility of highly adaptive characters (in particular those related to foraging ecology) and underscore the problems that convergence can pose for attempts to recover phylogeny. They also demonstrate how the concept of natural data partitions and simple models of evolution (e.g., parsimony, likelihood, neutrality) can be used to test the accuracy of independent phylogenetic estimates and provide arguments in favor of one tree topology over another.

opencc-zeroDec 2015View details →

Data from: Convergent evolution in social swallows (Aves: Hirundinidae)

Behavioral shifts can initiate morphological evolution by pushing lineages into new adaptive zones. This has primarily been examined in ecological behaviors, such as foraging, but social behaviors may also alter morphology. Swallows and martins (Hirundinidae) are aerial insectivores that exhibit a range of social behaviors, from solitary to colonial breeding and foraging. Using a well-resolved phylogenetic tree, a database of social behaviors, and morphological measurements, we ask how shifts from solitary to social breeding and foraging have affected morphological evolution in the Hirundinidae. Using a threshold model of discrete state evolution, we find that shifts in both breeding and foraging social behavior are common across the phylogeny of swallows. Solitary swallows have highly variable morphology, while social swallows show much less absolute variance in all morphological traits. Metrics of convergence based on both the trajectory of social lineages through morphospace and the overall morphological distance between social species scaled by their phylogenetic distance indicate strong convergence in social swallows, especially socially foraging swallows. Smaller physical traits generally observed in social species suggest that social species benefit from a distinctive flight style, likely increasing maneuverability and foraging success and reducing in-flight collisions within large flocks. These results highlight the importance of sociality in species evolution, a link that had previously been examined only in eusocial insects and primates.

Data from: Distinguishing between convergent evolution and violation of the molecular clock for three taxa

We give a non-technical introduction to convergence-divergence models, a new modeling approach for phylogenetic data that allows for the usual divergence of lineages after lineage-splitting but also allows for taxa to converge, i.e. become more similar over time. By examining the 3-taxon case in some detail we illustrate that phylogeneticists have been ``spoiled'' in the sense of not having to think about the structural parameters in their models by virtue of the strong assumption that evolution is tree-like. We show that there are not always good statistical reasons to prefer the usual class of tree-like models over more general convergence-divergence models. Specifically we show many 3-taxon data sets can be equally well explained by supposing violation of the molecular clock due to change in the rate of evolution along different edges, or by keeping the assumption of a constant rate of evolution but instead assuming that evolution is not a purely divergent process. Given the abundance of evidence that evolution is not strictly tree-like, our discussion is an illustration that as phylogeneticists we need to think clearly about the structural form of the models we use. For cases with four taxa we show that there will be far greater ability to distinguish models with convergence from non-clock-like tree models.

opencc-zeroJun 2019View details →

Data from: How phenotypic convergence arises in experimental evolution

Evolutionary convergence is a core issue in the study of adaptive evolution, as well as a highly debated topic at present. Few studies have analyzed this issue using a "real-time" or evolutionary trajectory approach. Do populations that are initially differentiated converge to a similar adaptive state when experiencing a common novel environment? Drosophila subobscura populations founded from different locations and years showed initial differences and variation in evolutionary rates in several traits during short-term (~20 generations) laboratory adaptation. Here we extend that analysis to 40 more generations to analyze (1) how differences in evolutionary dynamics between populations change between shorter and longer time spans, and (2) whether evolutionary convergence occurs after sixty generations of evolution in a common environment. We found substantial variation in longer-term evolutionary trajectories and differences between short and longer-term evolutionary dynamics. Though we observed pervasive patterns of convergence towards the character values of long-established populations, populations still remain differentiated for several traits at the final generations analyzed. This pattern might involve transient divergence, as we report in some cases, indicating that more generations should lead to final convergence. These findings highlight the importance of longer-term studies for understanding convergent evolution.

opencc-zeroDec 2008View details →

Data from: Phylogenetic Analyses of DNA and Allozyme Data Suggest that Gonioctena Leaf Beetles (Coleoptera; Chrysomelidae) Experienced Convergent Evolution in their History of Host-Plant Family Shifts

A phylogenetic analysis of the genus Gonioctena (Coleoptera, Chrysomelidae) based on allozyme data (17 loci) and mitochondrial DNA sequence data (three gene fragments, 1,391 sites) was performed to study the evolutionary history of host-plant shifts among these leaf beetles. This chrysomelid genus is characteristically associated with a high number of different plant families. The diverse molecular data gathered in this study are to a large extent congruent, and the analyses provide a well-supported phylogenetic hypothesis to address questions about the evolution of host-plant shifts in the genus Gonioctena. The most-parsimonious reconstruction of the ancestral host-plant associations, based on the estimated phylogeny, suggests that the Fabaceae was the ancestral host-plant family of the genus. Although most of the host-plant shifts (between different host species) in Gonioctena have occurred within the same plant family or within the same plant genus, at least eight shifts have occurred between hosts belonging to distantly related and chemically dissimilar plant families. In these cases, host shifts may have been simply directed toward plant species available in the environment. Yet, given that two Gonioctena lineages have independently colonized the same three new plant families, including four of the same new genera, some constraints are likely to have limited the different possibilities of interfamilial host-plant shifts.

Data from: Phylogenetic relationships and convergent evolution of ocean-shore ground beetles (Coleoptera: Carabidae: Trechinae: Bembidion and relatives)

Through phylogenetic analysis of seven genes, we show that there have been at least six independent entries into intertidal habitats in the history of bembidiine carabids, in the ancestors of: (i) Orzolina Machado, (ii) Bembidion (Desarmatocillenus Netolitzky), (iii) Bembidion laticeps (LeConte) + palosverdes Kavanaugh & Erwin, (iv) Bembidion laterale (Samouelle), (v) Bembidion umi Sasakawa and Bembidion quadriimpressum (Motschulsky) (which may represent two separate entries), and (vi) B. nigropiceum (Marsham). The following lineages are widely separated within the subtribe Bembidiina: Orzolina is sister to the genus Ocys Stephens; subgenus Desarmatocillenus appears to be sister to all Bembidion Latreille excluding subgenus Phyla Motschulsky; B. laticeps + B. palosverdes is a clade in the Bembidion series; B. laterale is a member of the Princidium Motschulsky complex; B. umi and B. quadriimpressum are related to the Nearctic Clade of the Ocydromus Clairville complex; B. nigropiceum is sister to B. praeustum Dejean among sampled species. There are three separate lineages of ocean‐shore bembidiines that are known to prey on amphipods, and adults of these lineages [Bembidion (Desarmatocillenus), B. laterale, and B. mandibulare Solier] have unusually wide heads with long mandibles. Also common among independent lineages restricted to ocean shores are prominent front angles of the prothorax, larger numbers of setae on the elytral disc, a notable sinuation in the margin of each elytron near its apex, and short, wide mesotarsi. The reasons for the repeated evolution of these features are not evident. Our results also suggest that inland species of the Nearctic Clade may have arisen from an ocean‐shore ancestor. The close genetic similarities between the gravel river shore dwelling B. praeustum and the intertidal specialist B. nigropiceum suggest that the striking morphological adaptations of B. nigropiceum to the intertidal zone arose rapidly. We make one nomenclatural change: we resurrect the subgenus Lymneops Casey to accommodate B. palosverdes and B. laticeps.

Data from: Agouti-related peptide 2 facilitates convergent evolution of stripe patterns across cichlid fish radiations

The color patterns of African cichlid fishes provide notable examples of phenotypic convergence. Across the more than 1200 East African rift lake species, melanic horizontal stripes have evolved numerous times. We discovered that regulatory changes of the gene agouti-related peptide 2 (agrp2) act as molecular switches controlling this evolutionarily labile phenotype. Reduced agrp2 expression is convergently associated with the presence of stripe patterns across species flocks. However, cis-regulatory mutations are not predictive of stripes across radiations, suggesting independent regulatory mechanisms. Genetic mapping confirms the link between the agrp2 locus and stripe patterns. The crucial role of agrp2 is further supported by a CRISPR-Cas9 knockout that reconstitutes stripes in a nonstriped cichlid. Thus, we unveil how a single gene affects the convergent evolution of a complex color pattern.

opennotspecifiedDec 2007View details →

FIGURE 1. NHM 2007.4 in A new species of Lissocidaris (Echinodermata: Echinoidea: Cidaridae) from the Philippines: convergent evolution among smooth-spined cidaroids

FIGURE 1. NHM 2007.4, holotype: A, aboral view; B, oral view; C, lateral view.

opencc-by-4.0Jun 2018View details →

FIGURE 2 in Convergent Evolution of a Eusuchian-Type Secondary Palate within Shartegosuchidae

FIGURE 2. Digital reconstructions and line drawings of Shartegosuchus asperapalatum (IGM 200/50) in A, dorsal view, B, ventral view of Shartegosuchus asperapalatum (IGM 200/50). Abbreviations: ang, angular; ant fos, antorbital fossa; ch, choana; d, dentary; ect, ectopterygoid; j, jugal; lac, lacrimal; m, maxilla; n, nasal; pal, palatine; pal fen, palatal fenestra; pf, prefrontal; pm, premaxilla; pty, pterygoid; sub fen, suborbital fenestra; sp, splenial; v, vomer.

FIGURE 13 in Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

FIGURE 13. Specimen of the crab Laeviprosopon punctatum (von Meyer, 1857) (NHMW 2017/0089/0033) from the Late Jurassic (Tithonian) of Ernstbrunn, eastern Austria. A, dorsal view of carapace. B, right-lateral view. C, frontal view. Scale bar width equals 2.0 mm.

FIGURE 12 in Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

FIGURE 12. Comparison of length-width ratios relative to specimen size for carapaces of three previously recognized brachyuran species that are synonymized herein: Europrosopon aculeatum (=E. verrucosum and E. barbulescuae). Specimens grew proportionally wider (allometric growth). Data: Appendix 4.

FIGURE 14 in Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

FIGURE 14. Specimen of the crab Prosopon josephcollinsi sp. nov. (NHMW 1990/0041/0738) from the Late Jurassic (Tithonian) of Ernstbrunn, eastern Austria. A, dorsal view of carapace. B, left-lateral view. C, frontal view. D, right-lateral view, angled. Scale bar width equals 5.0 mm.

FIGURE 10 in Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

FIGURE 10. Comparisons between specimens of the mid-Cretaceous crab Rathbunopon obesum (Van Straelen, 1944) from Koskobilo, Spain, and the crab Europrosopon aculeatum (von Meyer, 1857) from Ernstbrunn, eastern Austria (Tithonian, NHMW numbers), and the Kotouc quarry (locality 3 of level 6), Czech Republic (Tithonian, MAB and UF numbers). A, F, H, J, dorsal, frontal, upper orbital, and orbital views of R. obesum (MAB k3600). B, G, dorsal and frontal views of E. aculeatum (NHMW/1990 0041/4059). C, K, dorsal and orbital view of E. aculeatum (NHMW 2007z0149/0005). D, right-lateral view of R. obesum (MAB k3141). E, right-lateral view of E. aculeatum (MAB k3605). I, upper orbital view of E. aculeatum (UF 288756). For approximate size of H and J, see A and F. Scale bar width equals 2.0 mm.

FIGURE 16 in Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

FIGURE 16. Specimens of the crab Tanidromites scheffnerae Schweigert and Koppka, 2011, from the Late Jurassic (Tithonian) of Ernstbrunn, eastern Austria. A-C, G, dorsal views (NHMW 2014/0194/0988, 2014/0194/0314, 2014/ 0194/0312, and 1990/0041/1318, resp.). D-F, two left and one right views of augenrest (NHMW 1990/0041/1318, 2014/0194/0312, and 2014/0194/0314, resp.). H, I, L, two left- and one right-lateral views (NHMW 2014/0194/0314, 2014/0194/0312, and 2014/0194/0988, resp.). J, K, frontal views (NHMW 2014/0194/0312 and 2014/0194/0988, resp.). Scale bar width is 5.0 mm, except for D-F (1.0 mm).

FIGURE 4 in Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

FIGURE 4. Specimens of the crab Eodromites cristinarobinsae sp. nov. from the mid-Cretaceous (lower upper Albian) reef limestones of Koskobilo, northern Spain. A-C, dorsal views (holotype MGSB78750, paratype UF 271883, and paratype MAB k3592, resp.). D-F, frontal views (MGSB78750, UF 271883, and MAB k2638, resp.). G, H, right- and left-lateral views (MAB k2950 and MAB k2953, resp.). I, oblique view of lateral part of orbital structure with fissure (MAB k2626); upper orbital margin incomplete; height figure ~1.0 mm. A, D, G, and H colored dark and subsequently coated with ammonium chloride prior to photography; from Klompmaker et al. (2012, figure 5B, H, J, and K, reproduced with permission). Those images are not published under the terms of the CC-BY license of this article. For permission to reuse, please see Klompmaker et al. (2012). Scale bar width equals 1.0 mm.

FIGURE 11 in Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

FIGURE 11. Specimens of the crab Europrosopon aculeatum (von Meyer, 1857) comb. nov. from the Late Jurassic (Tithonian) of Central Europe, all dorsal views. A, C, F, Specimens from Ernstbrunn, Austria (NHMW 1990/0041/3756, 2007z0149/0005, and 1990/0041/2520, resp., previously identified as Prosopon verrucosum by Schweitzer and Feldmann (2009d). B, Specimen (UF 288714) from the Kotouc quarry (locality 3 of level 6), Czech Republic. D, E, Specimens (LPBIII art 279 and LPBIII art 278, resp.) from Waypoint 162, Romania, previously identified as Prosopon barbulescuae (modified from Schweitzer et al., 2018, figure 13, reproduced with permission). Those images are not published under the terms of the CC-BY license of this article. For permission to reuse, please see Schweitzer et al. (2018). Note that the specimen in D is oriented toward the anterior portion of the carapace. Scale bar width equals 2.0 mm.

FIGURE 5 in Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

FIGURE 5. Specimens of the crab Navarradromites pedroartali Klompmaker et al., 2012, from the mid-Cretaceous (early late Albian) of Koskobilo, northern Spain. A-C, dorsal views (holotype MGSB77711, MAB k3593, and MAB k3591, resp.). D, F, frontal views showing somewhat different rostral tips (MAB k3018 and MAB k3591, resp.). E, K, right-lateral views (MAB k3593 and MAB k3591, resp.). G, H, views of orbital structure with fissure laterally (MAB k3591 and paratype MAB k3182, resp.); height G ~1.0 mm. I, frontal view of damaged upper orbital projection that is wider than tall (paratype MAB k3182). J, lower orbital margin (upper orbital margin is not complete), width figure ~0.5 mm (MAB k3593). A and D colored dark and subsequently coated with ammonium chloride prior to photography; from Klompmaker et al. (2012, figure 8D, I, reproduced with permission). Those images are not published under the terms of the CC-BY license of this article. For permission to reuse, please see Klompmaker et al. (2012). Scale bar width equals 1.0 mm.

FIGURE 9 in Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

FIGURE 9. Specimens of the crab Planoprosopon aff. P. hystricosus Schweitzer and Feldmann, 2009a, from the Late Jurassic (Tithonian) of Ernstbrunn, eastern Austria. A, C, dorsal views of carapace (NHMW 2017/0089/0034 and 1990/0041/0805). B, right-lateral view (2017/0089/0034). D, E, frontal views (2017/0089/0034 and 1990/0041/0805). Note the presence of an epicaridean parasite swelling (ichnotaxon Kanthyloma crusta Klompmaker et al., 2014) in the right branchial region in 1990/0041/0805. Scale bar width equals 1.0 mm.

FIGURE 17 in Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

FIGURE 17. Specimens of the crab Tanidromites sculpta (Quenstedt, 1858) from the Late Jurassic (Tithonian) of Ernstbrunn, eastern Austria (all except I, K, L), and the Late Jurassic (middle-late Oxfordian) of Niegowonice, southern Poland (I, K, L) for comparison. A-D, I, dorsal views (NHMW 1990/0041/5065, 1990/0041/0689, 1990/0041/3985, 2014/0194/0313, and I-F/MP/248/1495/08, resp.). E, F, frontal views (NHMW 2014/0194/0313 and 1990/0041/3985, resp.). G, J, K, right- and 2x left-lateral views (NHMW 1990/0041/5065, 1990/0041/3985, and I-F/MP/248/1495/08, resp.). J and K are taken at slightly different angles. H, L, straight on views of left orbital structure. (NHMW 1990/0041/ 3985 and I-F/MP/248/1495/08, resp.). Scale bar width is 2.0 mm, except for H and L (1.0 mm).

Data from: Convergent evolution of the ladder-like ventral nerve cord in Annelida

Background: A median, segmented, annelid nerve cord has repeatedly been compared to the arthropod and vertebrate nerve cords and became the most used textbook representation of the annelid nervous system. Recent phylogenomic analyses, however, challenge the hypothesis that a subepidermal rope-ladder-like ventral nerve cord (VNC) composed of a paired serial chain of ganglia and somata-free connectives represents either a plesiomorphic or a typical condition in annelids. Results: Using a comparative approach by combining phylogenomic analyses with morphological methods (immunohistochemistry and CLSM, histology and TEM), we compiled a comprehensive dataset to reconstruct the evolution of the annelid VNC. Our phylogenomic analyses generally support previous topologies. However, the so far hard-to-place Apistobranchidae and Psammodrilidae are now incorporated among the basally branching annelids with high support. Based on this topology we reconstruct an intraepidermal VNC as the ancestral state in Annelida. Thus, a subepidermal ladder-like nerve cord clearly represents a derived condition. Conclusions: Based on the presented data, a ladder-like appearance of the ventral nerve cord evolved repeatedly, and independently of the transition from an intraepidermal to a subepidermal cord during annelid evolution. Our investigations thereby propose an alternative set of neuroanatomical characteristics for the last common ancestor of Annelida or perhaps even Spiralia.