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Promesacanthus eppleri n. gen., n. sp., a mesacanthid (Acanthodii, Acanthodiformes) from the Lower Devonian of northern Canada
No full textHanke, Gavin F. (2008): Promesacanthus eppleri n. gen., n. sp., a mesacanthid (Acanthodii, Acanthodiformes) from the Lower Devonian of northern Canada. Geodiversitas 30 (2): 287-302, DOI: http://doi.org/10.5281/zenodo.537857
FIG. 2. — Promesacanthus eppleri n. gen., n in Promesacanthus eppleri n. gen., n. sp., a mesacanthid (Acanthodii, Acanthodiformes) from the Lower Devonian of northern Canada
No full textFIG. 2. — Promesacanthus eppleri n. gen., n. sp.: A, photograph of the entire body of the holotype (UALVP 41860); B, camera lucida drawing of the same specimen with interpretation of structures. Scale bars: 1 cm.Published as part of Hanke, Gavin F., 2008, Promesacanthus eppleri n. gen., n. sp., a mesacanthid (Acanthodii, Acanthodiformes) from the Lower Devonian of northern Canada, pp. 287-302 in Geodiversitas 30 (2) on page 292, DOI: 10.5281/zenodo.537857
FIG. 6 in Redescription of the acanthodian Gladiobranchus probaton Bernacsek & Dineley, 1977, and comments on diplacanthid relationships
No full textFIG. 6. — Photographs of articulated specimens of Gladiobranchus probaton Bernacsek & Dineley, 1977: A, portions of the head and branchial chamber (UALVP 42095); B, head and pectoral girdle (UALVP 41862). Scale bars: 1 cm.Published as part of Hanke, Gavin F. & Davis, Samuel P., 2008, Redescription of the acanthodian Gladiobranchus probaton Bernacsek & Dineley, 1977, and comments on diplacanthid relationships, pp. 303-330 in Geodiversitas 30 (2) on page 312, DOI: 10.5281/zenodo.537305
FIG. 8 in Redescription of the acanthodian Gladiobranchus probaton Bernacsek & Dineley, 1977, and comments on diplacanthid relationships
No full textFIG. 8. — Camera lucida drawings: A, ornamented surface of the spathiform opercular plates of Uraniacanthus spinosus Miles, 1973 (BNMH P.16612); B, right scapulocoracoid of Gladiobranchus probaton Bernacsek & Dineley, 1977 (UALVP 41862) after Davis (2002: figs 2.3.2b, 5.3a). Scale bars: A, 1 cm; B, 0.25 cm.Published as part of Hanke, Gavin F. & Davis, Samuel P., 2008, Redescription of the acanthodian Gladiobranchus probaton Bernacsek & Dineley, 1977, and comments on diplacanthid relationships, pp. 303-330 in Geodiversitas 30 (2) on page 314, DOI: 10.5281/zenodo.537305
FIG. 6 in A re-examination of Lupopsyrus pygmaeus Bernacsek & Dineley, 1977 (Pisces, Acanthodii)
No full textFIG. 6. — Lupopsyrus pygmaeus Bernacsek & Dineley, 1977: A, patch of typical body scales; B, detail of a scale in basal view; C, detail of body scale with a broken tip showing the pulp cavity; D, single body scale in oblique, crown view; E, detail of a body scute with crown intact; F, detail of a body scute with a broken crown showing the large, central pulp cavity; G, drawing of a body scale in sagittal section. A-C, G, UALVP 43409; D-F, UALVP 42530. Abbreviations: see Material and methods. Scale bars: A, 0.5 mm; B-G, 100 µm.Published as part of Hanke, Gavin F. & Davis, Samuel P., 2012, A re-examination of Lupopsyrus pygmaeus Bernacsek & Dineley, 1977 (Pisces, Acanthodii), pp. 469-487 in Geodiversitas 34 (3) on page 481, DOI: 10.5252/g2012n3a1, http://zenodo.org/record/538152
Karatajūtė-Talimaa, 1968, with an anal fin spine
No full textFIG. 4. — Polymerolepis whitei Karatajūtė-Talimaa, 1968 (all from UALVP 45015): A, scales at the base of the anal fin spine; B, scales mid-way along the leading edge of the anal fin web; C, scales in side view from near the distal tip of the anal fin web; D, scales midway along the leading edge of the hypochordal lobe of the caudal fin; E, scales from the tip of the hypochordal lobe of the caudal fin; F, scales from the base of the hypochordal lobe of the caudal fin. Scale bars: 4 mm.Published as part of Hanke, Gavin F., Wilson, Mark V. H. & Saurette, Fernand J., 2013, Partial articulated specimen of the Early Devonian putative chondrichthyan Polymerolepis whitei Karatajūtė-Talimaa, 1968, with an anal fin spine, pp. 529-543 in Geodiversitas 35 (3) on page 537, DOI: 10.5252/g2013n3a2, http://zenodo.org/record/453812
Gladiobranchus probaton Bernacsek & Dineley 1977
No full text<i>Gladiobranchus probaton</i> Bernacsek & Dineley, 1977 (Figs 1-13) <p>HOLOTYPE. — NMC 22700A.</p> <p>MATERIAL EXAMINED. — UALVP 19259, 32448, 32469, 38679, 41669, 41857, 41858, 41862, 42095, 44046, scales: 45366-45396.</p> <p> HORIZON AND AGE. — All known <i>Gladiobranchus</i> specimens are from the single UALVP locality 129 in Early Devonian (Lochkovian) dark grey argillaceous limestone of the Delorme Group, Delorme Formation, District of Mackenzie.</p> <p> TYPE LOCALITY. — In talus below the UALVP locality 129 (62°32”N, 127°45”W), also known as the MOTH fish layer, MOTH section, section 43 (Gabrielse <i>et al</i>. 1973), Central Mackenzie Mountains, Northwest Territories, Canada. The descriptive geology of the locality was summarized by Hanke <i>et al</i>. (2001), Hanke (2002), Hanke & Wilson (2004), and Zorn <i>et al</i>. (2005).</p> <p>REVISED DIAGNOSIS. — Diplacanthoid acanthodians with rostral plates having enlarged tubercles along posterolateral edges; an enlarged anterior circumorbital plate with radiating rows of tubercles situated posterolateral to the rostrum; single ovate, enlarged postorbital plate ornamented with spiky tubercles associated with the circumorbital plate series; perichondrally ossified Meckel’s cartilage with strong symphyseal connection; dorsally-directed process positioned mid-way along Meckel’s cartilage; dermal mandibular splint absent; heavily-ornamented, spathiform opercular plates cover the entire gill chamber laterally; pectoral dermal plate armour absent; two pairs of prepectoral spines inserted between scales on the isthmus; axial ridge of scapular blade of scapulocoracoid separating postbranchial and posterior laminae of coracoid region; medial surface of scapulocoracoid flat; paired fin-spines possessing simple reclined nodular ornament on anterior-most ribs; anterior dorsal fin-spine approximately twice the length of posterior dorsal fin-spine; enlarged body scales with fine surface ridges surround base of fin-spines; body scales behind branchial chamber, on fins, and along dorsal and ventral midline posterior as far as caudal peduncle ornamented with fine parallel ridges whereas body scales at mid-flank possess unornamented crowns; body scale histology consisting of few, thick growth zones in crown and flat to slightly tumid mass of basal tissue; body scale neck and basal tissue expanded perpendicular to long-axis of scale crown.</p>Published as part of <i>Hanke, Gavin F. & Davis, Samuel P., 2008, Redescription of the acanthodian Gladiobranchus probaton Bernacsek & Dineley, 1977, and comments on diplacanthid relationships, pp. 303-330 in Geodiversitas 30 (2)</i> on page 306, DOI: <a href="http://zenodo.org/record/5373050">10.5281/zenodo.5373050</a>
Acanthodii Owen 1846
No full textClass ACANTHODII Owen, 1846 REMARKS The order Climatiiformes is thought to contain the most primitive acanthodian species, including Lupopsyrus pygmaeus. The diagnosis of the Climatiiformes provided by Denison (1979) included acanthodians with enlarged cranial tesserae and scales, a dermal shoulder girdle including pinnal and lorical plates, and in some cases, prepectoral spines, plus all climatiiforms possessed two dorsal fins. Not surprisingly, the diagnosis of the order has changed with each new publication as new taxa are shoe-horned into the classification scheme. Gagnier & Wilson (1996a) revised this diagnosis and limited the climatiiform character list to include: scales with, or derived from Nostolepis Pander, 1856, type histological structure, the presence of two dorsal fins, and the presence of fairly large head scales to accommodate Kathemacanthus rosulentus Gagnier & Wilson, 1996a, and Brochoadmones milesi Bernacsek & Dineley, 1977; note that K. rosulentus has been recently reclassified as a putative chondrichthyan based primarily on scale growth (Hanke & Wilson 2010). Gagnier & Wilson (1996a) excluded pinnal and lorical plate armour and prepelvic spine presence from their climatiiform character list, to incorporate their new taxa and because mesacanthids also possess prepelvic spines (see: Egerton 1861; Miles 1966, 1973; Denison 1979; Gagnier 1996; Upenice 1996; Cumbaa & Schultze 2002; Hanke 2008). Some mesacanthids also have fairly large head scales, so we think that this feature too is not unique to climatiiforms. Support for Gagnier & Wilson’s decision to eliminate prepectoral and prepelvic spines as a climatiiform characteristic follows the discovery of several new taxa from MOTH which possess these spines but lack characteristic scales and perichondral bone of acanthodians (Hanke & Wilson 1998, 2004, 2010; Wilson& Hanke 1998). This leaves us with: 1) scales derived from a Nostolepis - type of histology; and 2) two dorsal fins, as potential features defining the order Climatiiformes.Two dorsal fins are present in non climatiid acanthodians such as: diplacanthids, ischnacanthids and also gyracanthids plus early chondrichthyans, osteichthyans and sarcopterygians (Janvier 1996). Furthermore, most “ Nostolepis ” species are known only from isolated microremains, with the exception of a few taxa (Valiukevičius 2003a; Burrow & Turner 2010), and acritolepid ischnacanthiforms have Nostolepis - type scale histology (Valiukevičius & Burrow 2005). As a result we cannot support the definition of climatiiform acanthodians using histological features now known to exist outside the group. This historical perspective shows there are no synapomorphies to unite the climatiiforms as historically defined (Janvier 1996; Hanke 2001; Davis 2002; Hanke & Wilson 2004; Burrow & Turner 2010), and as a result, the higher classification of L. pygmaeus is left open pending detailed reexamination of climatiiform fishes.Published as part of Hanke, Gavin F. & Davis, Samuel P., 2012, A re-examination of Lupopsyrus pygmaeus Bernacsek & Dineley, 1977 (Pisces, Acanthodii), pp. 469-487 in Geodiversitas 34 (3) on page 472, DOI: 10.5252/g2012n3a1, http://zenodo.org/record/538152
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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