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Measures
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Description of measurements and references
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| Standard length |
From the tip of the snout to the posterior margin of the last plate located on the caudal peduncle (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Head length |
From the tip of the snout to the distal margin of the parieto- supraoccipital process (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Body depth at dorsal-fin origin |
From the point immediately anterior to the dorsal-fin spine to the ventral midline of the body, along a vertical line (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Body width at dorsal-fin origin |
Width of the body immediately anterior to the dorsal fin (Isbrücker, Nijssen, 1978) |
| Body width at anal-fin origin |
Width of the body immediately anterior to the anal fin (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Predorsal length |
From the tip of the snout to the posterior margin of the nuchal plate (Boeseman, 1971; “predorsal shield” in Isbrücker, Nijssen, 1978) |
| Post-dorsal length |
From the base of the last dorsal-fin ray to the posterior margin of the last plate located on the caudal peduncle (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Postanal length |
From the base of the last anal-fin ray to the posterior margin of the last plate located on the caudal peduncle (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Prepelvic length |
From the tip of the snout to the base of the pelvic-fin spine (Vera-Alcaraz et al., 2012) |
| Distance from parieto-supraoccipital to dorsal fin |
Between the distal margin of the parieto-supraoccipital process and the base of the dorsal-fin spine (Boeseman, 1971) |
| Caudal peduncle depth |
Minimum depth of the caudal peduncle (Boeseman, 1971) |
| Dorsal-fin length |
Total length of the first dorsal-fin ray, measured from the base to its tip (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Pectoral-fin length |
Total length of the first pectoral-fin ray, measured from the base to its tip (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Pelvic-fin length |
Total length of the first pelvic-fin ray, measured from the base to its tip (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Anal-fin length |
Total length of the first anal-fin ray, measured from the base to its tip (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Pectoral-fin origin to pelvic-fin origin |
From the anterior face of the pectoral-fin spine base to the pelvic-fin spine base “thoracic length” in Isbrücker, Nijssen, 1978 |
| Pelvic-fin origin to anal-fin origin |
From the anterior face of the pelvic-fin spine base to the anal-fin spine base abdominal length in Isbrücker, Nijssen, 1978 |
| Distance between cleithral processes |
Distance between tips of contralateral cleithral processes approximately equivalent to cleithral width of Isbrücker, Nijssen, 1978 |
| Head width |
Maximum width of head, from opercle to contralateral opercle (Boeseman, 1971) |
| Head depth |
From the posterior margin of the parieto-supraoccipital process to the ventral midline of the body, along a vertical line (Boeseman, 1971; Isbrücker, Nijssen, 1978) |
| Snout-mouth length |
From the tip of the snout to the anteriormost point in the pre-oral arch (i.e., the arch formed by the posterior margins of the plates that surround the mouth anteriorly; Retzer, Page, 1996; equivalent to “length of lower armored snout” of Boeseman, 1971) |
| Minimum width of snout |
Measured at the point where the snout begins to taper abruptly towards its tip (see Dopazo et al., 2023, fig. 1A) |
| Maximum width of snout |
Measured at the base of the rostrum, where it is crossed by a transversal line through to the anteriormost point in the pre-oral arch (see Dopazo et al., 2023, fig. 1C) |
| Snout length |
From the tip of the snout to the anteriormost point of the orbital margin (Isbrücker, Nijssen, 1978) |
| Eye diameter |
Horizontal length of the orbit (Boeseman, 1971) |
| Interorbital width |
Minimum distance between the orbital margins (Boeseman, 1971) |
| Postorbital head length |
From posterior margin of parieto-supraoccipital process (at midline of body) to closest point on posterior margin of orbit (Boeseman, 1971) |
| Internarial distance |
Minimum bony distance between the left and right nostrils (Vera-Alcaraz et al., 2012) |