DOI: 10.5061/dryad.f4qrfj6ss
title: Data from: Large-bodied sabre-toothed anchovies reveal unanticipated ecological diversity in early Palaeogene teleosts

description: Many modern groups of marine fishes first appear in the fossil record
 during the early Palaeogene (66–40 million years ago), including iconic
 predatory lineages of spiny-rayed fishes that appear to have originated in
 response to ecological roles left empty after the Cretaceous/Palaeogene
 extinction. The hypothesis of extinction-mediated ecological release
 likewise predicts that other fish groups have adopted novel predatory
 ecologies. Here we report remarkable trophic innovation in early
 Palaeogene clupeiforms (herrings and allies), a group whose modern
 representatives are generally small-bodied planktivores. Two forms, the
 early Eocene (Ypresian) †Clupeopsis from Belgium and a new genus from the
 middle Eocene (Lutetian) of Pakistan, bear conspicuous features indicative
 of predatory ecology, including large size, long gapes, and caniniform
 dentition. Most remarkable is the presence of a single, massive vomerine
 fang offset from the midline in both. Numerous features of the
 neurocranium, suspensorium, and branchial skeleton place these taxa on the
 engraulid (anchovy) stem as the earliest known representatives of the
 clade. The identification of large-bodied, piscivorous anchovies
 contributes to an emerging picture of a phylogenetically diverse guild of
 predatory ray-finned fishes in early Palaeogene marine settings, which
 include completely extinct lineages alongside members of modern marine
 groups and taxa that are today restricted to freshwater or deep-sea
 environments.
description: The holotypes of †<i>Clupeopsis straeleni</i> (MRHNB
 IG 8630) and †<em>Monosmilus chureloides </em>(GSP-UM 37), as
 well as representative examples of extant clupeiforms, were imaged using
 Nixon XT H 225ST industrial μCT scanners at the University of Michigan and
 the Natural History Museum, London. Reconstructed datasets were visualized
 and segmented using Mimics v. 19.0 (Materialise, Belgium). Models of
 segmented skeletal elements were exported as surface files (.ply) and
 rendered as high-quality images in Blender v. 2.79 (blender.org).
 Individual scanning parameters of new tomograms generated for this study
 are provided in the usage notes.
description: <strong>3D surface models of †<em>Clupeopsis
 straeleni</em> (MRHNB IG 8630, holotype)</strong>
 .ply files of cranial bony elements preserved in
 †<em>Clupeopsis straeleni </em>(MRHNB IG 8630, holotype) and
 segmented using Mimics v. 19.0.
 Clupeopsis_straeleni_plyFiles.zip 
 <strong>3D surface models of †<em>Monosmilus
 chureloides</em> gen. et sp. nov. (GSP-UM 37,
 holotype)</strong> .ply files of bony
 elements preserved in †​​​​​​​<em>Monosmilus chureloides
 </em>gen. et sp. nov. (GSP-UM 37, holotype) and segmented using
 Mimics v. 19.0.
 Monosmilus_chureloides_plyFiles.zip 
 <strong>3D surface models of <em>Odaxothrissa
 mento</em></strong> .ply files
 of <em>Odaxothrissa mento</em> (UMMZ 195016) cranial bones
 segmented using Mimics v. 19.0.
 Odaxothrissa_mento_plyFiles.zip 
 <strong>3D surface models of <em>Chirocentrus
 dorab</em></strong> .ply files
 of <em>Chirocentrus dorab</em> (UMMZ 238306) cranial bones
 segmented using Mimics v. 19.0.
 Chirocentrus_dorab_plyFiles.zip 
 <strong>3D surface models of
 <em>Setipinna </em>[<em>Lycothrissa</em>] <em>crocodilus</em></strong> .ply files of <em>Setipinna </em>[<em>Lycothrissa</em>] <em>crocodilus</em> (UMMZ 209911) cranial bones segmented using Mimics v. 19.0. Lycothrissa_crocodilus_plyFiles.zip <strong>µCT data as DICOM stack for</strong> <strong>†<em>Clupeopsis straeleni</em> (MRHNB IG 8630, holotype)</strong> .7z file containing micro-computed tomography data for †​​​​​​​​​​​​​​<em>Clupeopsis straeleni </em>(MRHNB IG 8630, holotype) as a DICOM image stack. Voltage: 210 kV; current: 200 μA; exposure: 1000 ms; filter: 1.5 mm tin; reflection target: tungsten; effective pixel size: 65.432 μm; scanning facility: Natural History Museum, London, Imaging and Analysis Centre. Clupeopsis_straeleni_MRHNB_IG_8630_dcm.7z <strong>µCT data as DICOM stack for</strong> <strong>†<em>Monosmilus chureloides</em> gen. et sp. nov. (GSP-UM 37, holotype)</strong> .7z file containing micro-computed tomography data for †​​​​​​​<em>Monosmilus chureloides</em> gen. et sp. nov. (GSP-UM 37, holotype) as a DICOM image stack. Voltage: 190 kV; current: 205 μA; exposure: 1415 ms; filter: 1.5 mm copper; reflection target: tungsten; effective pixel size: 57.94 μm; scanning facility: University of Michigan CTEES. Monosmilus_chureloides_GSP-UM_37_dcm.7z <strong>µCT data as DICOM stack for</strong> <b><i>Odaxothrissa mento</i></b> .7z file containing micro-computed tomography data for the cranial region of <i>Odaxothrissa mento</i> (UMMZ 195016) as a DICOM image stack. Voltage: 95 kV; current: 175 μA; exposure: 1000 ms; filter: none; reflection target: tungsten; effective pixel size: 19.97 μm; scanning facility: University of Michigan CTEES. Odaxothrissa_mento_UMMZ_195016_dcm.7z <strong>µCT data as DICOM stack for</strong> <b><i>Chirocentrus dorab</i></b> .7z file containing micro-computed tomography data for the cranial region of <em>Chirocentrus dorab</em> (UMMZ 238306) as a DICOM image stack. Voltage: 105 kV; current: 160 μA; exposure: 1000 ms; filter: none; reflection target: tungsten; effective pixel size: 36.43 μm; scanning facility: University of Michigan CTEES. Chirocentrus_dorab_UMMZ_238306_dcm.7z <strong>µCT data as DICOM stack for</strong> <b><i>Chirocentrus nudus</i></b> .7z file containing micro-computed tomography data for the cranial region of <em>Chirocentrus nudus</em> (UMMZ 213502) as a DICOM image stack. Voltage: 105 kV; current: 160 μA; exposure: 1000 ms; filter: none; reflection target: tungsten; effective pixel size: 39.00 μm; scanning facility: University of Michigan CTEES. Chirocentrus_nudus_UMMZ_213502_dcm.7z <strong>µCT data as DICOM stack for</strong> <strong><em>Setipinna </em>[<em>Lycothrissa</em>] <em>crocodilus </em>and <em>Lycengraulis grossidens</em></strong> .7z file containing micro-computed tomography data for the cranial regions of <em>Setipinna </em>[<em>Lycothrissa</em>] <em>crocodilus</em> (UMMZ 209911; specimen on the left in the scan) and <em>Lycengraulis grossidens</em> (UMMZ 143053; specimen on the right in the scan) as a DICOM image stack. Voltage: 100 kV; current: 170 μA; exposure: 1000 ms; filter: none; reflection target: tungsten; effective pixel size: 22.55 μm; scanning facility: University of Michigan CTEES. Lycothrissa_crocodilus_UMMZ_209911_Lycengraulis_grossidens_UMMZ_143053_dcm.7z