Tofino Basin elasmobranch dermal denticles have a lustrous crown that sits on a pedicle or base. The shape (e.g., lanceolate, rhomboid, circular, etc.) of the dermal denticle crown, its ornamentation (e.g., lines, ridges platforms, furrows, etc.), and the type of pedicle (e.g., Johns et al. 1997) are important characteristics to complete identification (Figure 20). Elasmobranch dermal denticles are commonly smaller than elasmobranch teeth and not as robust. Dermal denticles are commonly inclined anterior to posterior with the attachment of the pedicle positioned near the anterior margin leaving a significant region of the posterior subcrown that is unoccupied by the pedicle. Some dermal denticles have the pedicle positioned directly under the crown but the pedicle is distinctly smaller than the crown and the crown is usually horizontal (flat-topped), dome-shaped, or lobed. Elasmobranch teeth have a tooth base that is almost always directly below the crown base and occupies most of the subcrown surface.

Remarks: Tofino Basin specimens have a crown outline that is lanceolate-shaped, symmetric, approximately flat, and length greater than width but less than two times width. The posterior margin has three peaks with the median peak not greater than three times height of lateral peaks and depressions between peaks are U-shaped. The anterior margin is undulating with a short V-shaped mesial protrusion and a thin longitudinal line may be at the margin edge. The upper crown surface has three to five similarly raised ridges that extend from the anterior margin to posterior margin. The single mesial ridge is longer than lateral ridges. The subcrown may have faint vertical lines and the pedicle is missing.

The Tofino Basin specimens differ from short side peaks differentiated margin by not having a mesial ridge that is significantly more raised and differentiated from the lateral ridges and by having a median peak that is less than three times the height of the lateral peaks. Short side peaks differentiated margin ranges from upper Eocene to upper Oligocene (Doyle et al. 1974, p. 836). Questionable specimens of short side peaks differentiated margin have a damaged or not well-developed posterior dentate margin.

Occurrence: 3 specimens, 5 questionable specimens; Hesquiat Peninsula, Flores Island, and offshore well Shell-Anglo Pluto I-87; Short Side Peaks Differentiated Margin ichthyolith Zone; upper Eocene to middle Miocene.

a2/b2+6±12/c3/d1/e1/f1,2/g1/h1,2,3/i2+11+14/j3-5/k0,5,10/l3/m1/n11+15/p3/q0,1/r0,1/s1

Characters: Crown outline lanceolate to polygonal-shaped; longer than wide; with three peaks on dentate margin and U-shaped depressions between peaks; median peak 2-3 times as long as lateral peaks; anterior longitudinal ridge runs approximately parallel to undulating anterior margin (opposite dentate margin); ridges approximately parallel, long (extend from anterior longitudinal ridge to dentate margin), and commonly three (occasionally 4 or 5); median ridge forks near anterior margin with two ridges departing near same spot on median ridge, each extending to anterior longitudinal ridge at a position between median and lateral ridge, and each (plus anterior longitudinal ridge) form a small mesial anterior protrusion; addition short forking may occur near anterior longitudinal line; not curved from side-to-side but equally undulating; anterior margin prominently overhangs crown/pedicle junction. Subcrown unornamented. Pedicle tetrahedroid; smaller than crown; commonly not well preserved; positioned near anterior margin; base surface flat with tetrapetaloid to rounded-rhombic margins; vascularisation hemiaulacorhize.

Remarks: Three peaks forked median ridge is distinct and mainly differs from short side peaks differentiated margin and three similar peaks Doyle et al. 1974 by having an anterior-forked median ridge and its associated anterior mesial protrusion.

Occurrence: 4 specimens, 6 probable fragments, 1 slightly modified specimen similar to this subtype; near Matlahaw Point on Hesquiat Peninsula, and Rafael Point on Flores Island; offshore well Shell-Anglo Pluto I-87; Three Peaks Forked Median Ridge ichthyolith interval; common in Oligocene, ?reworked from Cretaceous to Eocene strata.

Characters: Crown outline rhomboid-shaped; longer than wide (ratio 1.3–1.5:1); with prominent (very raised) median ridge line that bifurcates near the margin opposite the acute prominence; median and two other ridges converge at apex of acute prominence and at other end each contacts one crown basal corner; margin opposite acute prominence rounded, moderately narrow and extended, and with concave sides; acute prominence fairly erect at about 80-85^°, margins slightly sigmoidal, height similar to crown width; basal margins continuous and smooth; subsurface outline approximately rhomboid; pedicle absent.

Remarks: The biggest similarities to rhombus kite are the high mesial ridge and a rhombus outline. The Hesquiat Peninsula specimen differs by having two additional ridges that radiate from the acute prominence – each to an outer margin; a ridge line that bifurcates near the margin opposite the acute prominence, sinuous margins on the acute prominence; and concave margins opposite the acute prominence. Rhombus kite is believed to occur in the Paleogene (Gupta 1991).

Occurrence: 1 specimen; Estevan Point, Hesquiat Peninsula; deposited in Oligocene strata, probably reworked from older strata.

Remarks: Tofino Basin specimens have a crown: outline that is kite-shaped, longer than or about equally as long as wide (ratio 1-2:1), and with one median ridge that is more raised near the margin opposite the acute prominence that may curve downwards (Figure 24.3.2). Crown lateral ridges are absent or short near the margins. The crown margins opposite the acute prominence have concave sides, and a rounded moderately narrow and extended protrusion. Acute prominence margins are concave to slightly sigmoidal with a thin transparent flange-like extension. All margins are continuous and smooth. A thin longitudinal line may be present along the margin opposite the acute prominence. The crown subsurface has a mesial ridge (Figure 24.1.2). The pedicle is commonly missing or broken and when present, is short truncate and wider than crown on margins opposite the acute prominence. The anterior crown/pedicle junction is located at the anterior crown edge and the posterior junction at centre or posterior of centre. The pedicle base is concave, approximately rhomboid-shaped, may have anterior bulge (Figure 24.2.1), and margins may be undulating.

Lanceolate median line Winfrey et al. 1987 has one mesial ridge like these Hesquiat Peninsula specimens but was not chosen because it is lanceolate-shaped and does not have four distinct sides. Kite-shaped longitudinal line ranges from the Maestrichtian through the Oligocene (Doyle and Riedel 1979a, p. 43).

Occurrence: 11 specimens, 2 questionable fragments; near Matlahaw Point, Hesquiat Peninsula; Three Peaks Forked Median Ridge ichthyolith interval; Oligocene; ?reworked from Eocene through Cretaceous strata.

Characters: Crown outline kite-shaped; longer than or about equally as long as wide (ratio 1-1.5:1); with one median ridge that is more raised near margin opposite acute prominence and may curve downwards, and two long additional lateral ridges; margins opposite acute prominence with straight or undulating sides and a short V-shaped protrusion; acute prominence margins straight to slightly convex with thin transparent flange-like extension on both margins that is continuous and smooth; longitudinal line along margin opposite acute prominence; subsurface with mesial ridge. Pedicle short truncate and wider than crown on margins opposite acute prominence; anterior crown/pedicle junction located at anterior crown edge and posterior junction at centre or posterior of centre; base concave, rounded to tetrapetaloid, and margins may be undulating.

Remarks: The specimens differ from plain and lined lanceolate Doyle et al. 1978 by having acute prominence margins that are straight to slightly convex and four margins that are approximately distinct. These specimens differ from kite-shaped longitudinal line by having three long crown ridges, straight to slightly convex acute prominence margins, a less pronounced anterior protrusion, and margins opposite the acute prominence that are straight to undulating.

Occurrence: 4 specimens; near Matlahaw Point, Hesquiat Peninsula; Three Peaks Forked Median Ridge ichthyolith interval; Oligocene, ?reworked from Cretaceous to Eocene strata.

a4/b2±6±12/c2,4/d4±(7,8)+10±13/e3/f3,4/g1/h1,2/i1,2/j(4,5,6)+11+13/k0,1,2,4±8/l1,2/m0,9/n0,3,4

Remarks: Tofino Basin specimens are about equally long as wide or slightly longer and have a crown outline that is rhomboid to lanceolate-shaped, a posterior margin with one short acute or obtuse apex, and an irregular to undulating anterior margin without a mesial protrusion that may slightly overhang the pedicle or slope directly down to the pedicle. The crown has 3-6 long and prominent ridges and furrows which converge at the posterior margin near the acute prominence and may bifurcate near anterior margins especially when the crown has a steeper or more erect inclination (Form C, Form D, and Form E). The crown mesial platform is lanceolate-shaped, extends anterior to posterior, commonly broad, centrally highest, and not well developed (ridge height and furrow depth similar). Two crown wings are lower in height than, on each side of, and positioned mainly at anterior end of the mesial platform. Most of the subcrown surface is occupied by the pedicle with only a small amount of subapical region exposed. The pedicle is anterior, wider than the crown and short truncate. The crown looks skirted or fringed. Vascularisation is anaulacorhize or indeterminate with the subsurface convex or convex with an anterior bulge. The anterior crown/pedicle junction is located at the anterior crown edge and posterior junction at centre or posterior of centre.

Pointed and skirted is distinctive by having a short and broad pedicle (especially at anterior) making it look skirted. It occurs in the Campanian through lower Eocene and rarely in the later Cenozoic (Doyle and Riedel 1979a, p. 38).

Pointed and skirted dermal denticles show many similarities (shape, ridges, and pedicle) to Centrophorus granulosus (Bloch and Schneider 1801), an extant gulper shark of the Family Squalidae that is common to deep waters (100-1200 m) in the Mediterranean (Reif 1985, plate 5). These dermal denticles occur in many but not all of the same samples as the Superorder Squalimorphii teeth. A number of other variable characteristics (Table 5) are observed in the Tofino Basin specimens. In the future, these may be useful for subdivision of the subtype.

Occurrence: 42 specimens; Nootka Island, several locations on the Hesquiat Peninsula, and offshore well Shell-Anglo Pluto I-87; Pointed and Skirted ichthyolith interval; Upper Cretaceous to lower Eocene, reworked and deposited into upper Eocene and Oligocene strata.

Characters: Crown outline lanceolate to rectangular or pentagonal; longer than wide; with low inclination to almost horizontal; posterior margin with one short acute or obtuse apex; anterior margin rounded to truncated, overhangs pedicle, and without mesial protrusion. Mesial platform broad (occupies most of crown) and long (extends anterior to posterior), approximately lanceolate to pentagonal shaped, height not well developed (ridge height and furrow depth similar), may have short or long approximately parallel lines and ridges. Two narrow crown wings lower in height than and on each side of mesial platform, terminate before posterior apex. Most of subcrown surface occupied by pedicle with only a small amount of subapical region exposed. Pedicle similar to pointed and skirted; at anterior is wider than crown and short truncate, crown looks skirted or fringed; vascularisation anaulacorhize or indeterminate; subsurface convex; anterior crown/pedicle junction located at anterior crown edge and posterior junction at posterior of centre.

Remarks: These specimens differ from pointed and skirted Doyle et al. 1978 by having a low inclined to almost horizontal crown that has a lanceolate to rectangular/pentagonal shape, the ridges/lines are less developed and commonly shorter, and the mesial platform is broader.

Occurrence: 2 specimens Hesquiat Peninsula, and offshore well Shell-Anglo Prometheus H-68; Pointed and Skirted ichthyolith interval, Upper Cretaceous to lower Eocene, reworked and deposited into Oligocene and lower Miocene strata.

Characters: Crown outline lanceolate-shaped; longer than wide (height/width >1 and <3); with no surface ornament (smooth); upper surface flat; all margins rounded, convex, and continuous; subcrown unornamented. Within crown branching dendritic lines radiate from crown/pedicle junction. Pedicle short and significantly smaller than crown; positioned under crown anteriorly but not at anterior margin; possibly tetrahedroid; outline circular to rhombic; subsurface flat.

Remarks: The Tofino Basin specimens are similar to ogee lanceolate Tway et al. 1985 by having dendritic lines and differ by not having concave posterior margins and an acute posterior prominence. Ogee lanceolate is known to range in the lower Eocene to the middle Miocene.

Occurrence: 1 specimen, 2 fragments; offshore well Shell-Anglo Pluto I-87; Short Side Peaks Differentiated Margin ichthyolith Zone; Oligocene.

Some elasmobranch dermal denticles were rare but distinctive. Preliminary identifications of 11 elasmobranch dermal denticles (Forms A to K) include the CUIIS code, a brief description in the "remarks" section, and illustration(s). Future studies hopefully will result in the location of additional specimens so that comparative identifications can be made.

Remarks: Form A is lanceolate-shaped and approximately horizontal (low inclined), with a central circular depression, a convex-rounded anterior margin, and a dentate posterior margin with > 2 cusps.

Occurrence: 4 specimens; Hesquiat Peninsula and offshore wells Shell-Anglo Prometheus H-68 and Pluto I-87; Oligocene and lower Miocene.

Remarks: Form B is approximately lanceolate-shaped with a single mesial ridge that is highest at anterior margin and a V-shaped mesial protrusion at anterior margin. One lateral ridge is located on each side of a mesial ridge. Crown with one posterior apex or cusp and poor development of low and abraded lateral cusps. Subcrown with two long ridges/lines on a moderately broadly inflated central region. Base or pedicle is missing.

This specimen differs from kite-shaped longitudinal line Doyle et al. 1974 by having lateral cusps with some development and two ridges/lines on the inflated mesial region of the subcrown surface.

Occurrence: 1 specimen; offshore well Shell-Anglo Cygnet J-100; Bulbous Base ichthyolith Zone, lower Pliocene.

Remarks: Form C is asymmetric lanceolate-shaped with rounded and convex margins, a shallow rounded anterior protrusion, and 1 to 3 very short approximately parallel lines on the anterior margin. Much of the upper crown is unornamented and the subcrown has one mesial ridge. Pedicle damaged.

Occurrence: 1 specimen; offshore well Shell-Anglo Prometheus H-68; Oligocene.

Remarks: Form D is lanceolate-shaped with a single posterior apex and concave sides. Anterior margins are convex and undulating without an anterior longitudinal line/ridge. Crown has one long mesial ridge and one long lateral ridge on each side. Subcrown unornamented. Pedicle damaged.

Form D differs from plain and lined lanceolate Doyle et al. 1978 by having an undulating anterior margin.

Occurrence: 2 specimens; Hesquiat Peninsula; Oligocene, possibly reworked from older strata.

Remarks: Form E is lanceolate-shaped with a single convex-sided posterior apex. The anterior margins are convex and undulating without an anterior longitudinal line/ridge. The crown has four moderately short ridges (about one half length of crown) at anterior margin where the central two ridges form a short and not well-developed mesial platform. The subcrown is unornamented. The pedicle occupies much of the subcrown surface, is tetrahedroid, and the outline is rhomboid or tetrapetaloid.

Form E mainly differs from Form D by having four moderately short ridges (instead of 3 long) and convex posterior margins.

Occurrence: 1 specimen; Hesquiat Peninsula; Oligocene, possibly reworked from Cretaceous to Eocene strata.

Remarks: Form F is lanceolate-shaped with convex posterior margins and one apex. Anterior margins are undulating with short approximately parallel ridges/lines and a prominent anterior longitudinal ridge. The crown is convex both from anterior to posterior and from side-to-side (laterally). The central part of the crown is shiny and unornamented. The pedicle and subcrown are damaged.

Occurrence: 1 specimen; Hesquiat Peninsula; Oligocene, possibly reworked from Cretaceous to Eocene strata.

Remarks: Form G is lanceolate-shaped with a long and prominent mesial ridge with 2-3 anterior ridges that branch to form a prominent anterior platform and mesial protrusion. One deep furrow and two long lateral ridges are present on each side of the mesial ridge/platform. The posterior margin has a single apex with approximately convex sides. The anterior margin is undulating and has a prominent longitudinal ridge. The subcrown has a mesial line/ridge. The pedicle is tetrahedroid with a tetrapetaloid outline.

Occurrence: 2 specimens; offshore well Shell-Anglo Pluto I-87; upper Eocene to Oligocene; possibly reworked from older strata.

Remarks: Form H is elongate-lanceolate shaped and inclined (about 45^°) with an irregularly undulating anterior margin, a single rounded posterior apex with concave to sigmoidal sides, and a single upper crown mesial ridge. The pedicle is short with a concave subsurface.

Occurrence: 1 specimen; offshore well Shell-Anglo Pluto I-87; upper Oligocene and lower Miocene; possibly reworked from older strata.

Undescribed elasmobranch dermal denticle or possible tooth, Form I
Figure 37

a4/b2+10/c2/d4+10+14/e3/f0/g2/h1/i1,4/j4+11+13/k4,5/l1,2/m0,2/n0

Appendix 1.4.1

Remarks: Form I is small (<0.5mm) and distinct elongate-lanceolate shaped with crown ridges, lines, and small rounded nodes. In profile view, the crown is sigmoidal, inclined at about 45^°, and has minor or no overhang of the base at the anterior margin. The base is irregular and occupies much of the subcrown surface.

Occurrence: 3 specimens; offshore well Shell-Anglo Zeus D-14; upper Oligocene or lower Miocene, possibly reworked from older strata.

Undescribed elasmobranch dermal denticle, Form J
Figure 38

a4/b2+13/c2/d4+12/e3,4/f0/g0/h1/i1/j0/k1/l1/m0/n0

Appendix 1.4.1

Remarks: Form J is approximately pentahedral-shaped and moderately erect (inclined at about 50-60^°). The crown posterior apex is rounded and blunt with concave sides, and the apical and posterior surfaces have a scalloped texture. The anterior crown has two parallel ridges that form a moderately broad mesial platform that extends about halfway up the crown. One to two other ridges are short. The anterior margin is truncated. The subcrown is concave and unornamented. The pedicle is missing.

Form J was the only Tofino Basin ichthyolith with a scalloped texture on the crown. This texture is common to Recent shark (elasmobranch) dermal denticles of the Order Carcharhiniformes and some of its families including Scyliorhinidae, Triakidae, Carcharhinidae, and Sphyrnidae. Dermal denticles of some of the species of these sharks are illustrated in Reif (1985) but the scalloped pattern does not match that seen in Form J.

Occurrence: 1 specimen; offshore well Shell-Anglo Zeus D-14; upper Eocene/Oligocene or lower Miocene.

Undescribed elasmobranch dermal denticle, Form K
Figure 39
a4/b6+7/c2/d2+8/e1/f8/g3/h1/i1,2/j2+11/k1,2/l3/m1/n1

Appendix 1.4.1

Remarks: Form K is lanceolate to rhomboid-shaped, with a single mesial ridge that is highest at the anterior margin and a rounded to V-shaped anterior margin with convex sides. The primary posterior apex or cusp is damaged. Subsidiary cusps are possibly present with poor development on a rounded lateral margin. The subcrown is unornamented and concave. The pedicle is small and positioned at the anterior.

Form K differs from kite-shaped longitudinal line Doyle et al. 1974 by having convex instead of concave anterior margins and by not having a subcrown mesial ridge.

Occurrence: 2 specimens; offshore well Shell-Anglo Pluto I-87; upper Oligocene; possibly reworked from older strata.

SYSTEMATIC DESCRIPTIONS
(continued)

Elasmobranch Dermal Denticles

SYSTEMATIC DESCRIPTIONS (continued)

Elasmobranch Dermal Denticles

SYSTEMATIC DESCRIPTIONS
(continued)