Progress in the fish subset of the LRT now recovers the following interrelationships among gobies and their proximal outgroup taxon, Ophiocephalus (Fig 1). These ray-fin, bony fish derived from the catfish-spiny shark-placoderm side prefer shallow bottom environs rather than open water. Figure 1. These are the four gobies tested in the LRT, plus an outgroup taxon, Ophiocephalus. According to Wikipedia, “Goby is a common name for many species of small to medium sized ray-finned fish, normally with large heads and tapered bodies, which are found in marine, brackish and freshwater environments ..read more

Trying to understand the clade Stylinodontidae can be difficult. Basal taxa are incomplete. I made mistakes earlier with less experience. Now that a little time has passed and experience gained, here (Fig 1) is the current lineup of taxa leading to Stylinodon, all to scale. Vulpavus, from the Paleocene, is a proximal outgroup taxon. That taxon sheds light on the phylogenetic minaturization that attended the genesis of this clade, too. It’s really remarkable just how often this generally overllooked hypothesis comes into play at the genesis of clades recovered in the LRT. Figure 1. The clade o ..read more

Near and Thacker 2024 wrote, “Classification of the tremendous diversity of ray-finned fishes (Actinopterygii) began with the designation of taxonomic groups on the basis of morphological similarity. Starting in the late 1960s morphological phylogenetics became the basis for the classification of Actinopterygii but failed to resolve many relationships, particularly among lineages within the hyperdiverse Percomorpha.” The LRT is getting close to resolving all issues involved in fish systematics. “The introduction of molecular phylogenetics led to a dramatic reconfiguration of actinopterygian ph ..read more

As progress on the fish subset of the LRT continues several now obvious – but previously overlooked – connections continue to appear. Here’s the latest one (Fig 1). I did not see this coming, but perhaps should have anticipated it from the start. Here’s the problem: I thought the long spines on Diplacanthus (Fig 1) were derived traits. Turns out they are relatively primitive. Sometimes ‘convergence’ turns out to be homology. Figure 1. The spiny shark with really big spines turns out to be a basal taxon in the Acanthodii, rather than a highly derived one. Here the overlooked Gregorius – Diplac ..read more

Giannini et al 2024 reported, “Here a gliding performance gradient emerged of decreasing sink rate with increasing AR that eventually allowed applying available muscle power to achieve level flight using flapping, which is greatly facilitated in hyperdense air. This gradient strongly supports a gliding (trees-down) transition to powered flight in bats.” The study looked at Onychonycteris bats (Fig 1) from the Green River Formation (Early Eocene), widely considered the – warmest – period in the Cenozoic. Warmer air is always –  less – dense. That’s a pilot’s concern on hot summer days when ..read more

Several specimens of tiny (mouse-sized Sinobaatar created this generic chimaera  (Figs 1 –3) with close affinities to chipmunk-sized Rugosodon. Figure 1. Sinobaatar in situ. DGS colors and reconstuctions added here. The canine might be missing or absent. The premolars and molars are shaped like those in Rugosodon. As in rodents, the jugal is not exposed laterally. Figure 2. Skull of Sinobaatar from two specimens. DGS colors added here. This skull is compressed and torsioned. See Rugosodon for in vivo shapes. This clade of multituberculates nests between extant tree shrews + aye-ayes ..read more

Which came first: singing or talking?Several links on Google indicate: singing. If true, and I think there’s good evidence for this, then take a look at how primate singing began in this YouTube video of gibbons expressing their emotions, individually, much as birds do. Gibbons sing. Humans sing. Gorillas sing to themselves in contentment when eating. That was recently discovered. Chimps sing when they get excited, joining in with a chorus of other chimps. That has been known for a long time. Earlier here, here and here we looked at the overlooked gibbon-human more direct connection. On the o ..read more

Currie and Chen 2001 reported, “The [smaller] specimens of Sinosauropteryx prima [Fig 1] show skull and orbit proportions, and bone texture typical of immature stages.” In the LRT juveniles are phylogenetically recovered when these relatively small taxa nest conspicuously among relatively larger-to-much larger taxa. Since extant archosaurs change proportions during ontogenetic growth, similar changes should also be expected in fossil archosaurs. A changing morphology for a single taxon is a taxonomic nightmare. That is why juveniles are generally avoided. By contrast, pterosaurs and other othe ..read more

Several extinct fishhave a buffalo-like hump in their back (Fig 1). We’ll look at two today and more later. Figure 1. Middle Devonian Cheiracanthus compared to Late Jurassic Thaiichthys. These two humpbacked fish share several other traits despite their chronological separation. Cheiracanthus (Middle Devonian) (Fig 1) is a humpback spiny shark. The mandible is about as long as the skull. Thaiichthys (Late Jurassic) (Fig 1) shortens the jaw line and increases the hump size as the fins turn from spines to rays with a robust leading edge ray. The overall proportions and skull details indicate h ..read more

More revisions. This is how it goes when you try to reconstruct a fish skull, like Ticinolepis crassidens, that has seen a bit of facial bone dislocation and tessalation (Fig 1). DGS (= coloring the bones) is helpful because it avoids freehand, avoids arrows and abbreviations, is replicable by other workers, and brings out errors if elements don’t fit they way do in tentatively related taxa. It’s a learning tool currently enjoying wider use in µCT scans. This is what it means to ‘manipulate in Photoshop’, a practice the Wikipedia author meant to imply something other than an attempt at precisi ..read more