Centric Radial | Asterolampra insignis (I) | oamar3a800 | Internal view of valve. Open chambers of the raised rays appear as black bars. Species distinguished by trapezoidal blocks of areolae at the margin between the rays. |
Centric Radial | Asterolampra insignis (I) | oamar3a2000 | Internal view of central area. Detail of image oamar3a800. |
Centric Radial | Asterolampra insignis (I) | oamar3a4500 | Internal view of valve edge showing internal opening of a rimoportula at end of open chamber. Detail of image oamar3a800. |
Centric Radial | Asterolampra vulgaris (I) | oamar3b1100 | Internal view of eroded valve. Species distinguished by the pair of rows of closely packed pores on each side of the ray chamber. |
Centric Polar | Kittonia elaborata | oamar3c800 | Internal valve view. |
Centric Polar | Kittonia elaborata | oamar3c2500 | Internal view of rimoportulae in central area. Detail of image oamar3c800. |
Centric Polar | Kittonia elaborata | oamar3c3000 | Internal view of opening to one of the tubular processes. Detail of image oamar3c800. |
Centric Radial | Brightwellia coronata | oamar3d900 | External valve view. Diameter 89 µm. |
Centric Radial | Brightwellia coronata | oamar3d4000 | Detail of image oamar3d900. External view of ring of ovals and areolae. |
Centric Radial | Asterolampra vulgaris (E) | oamaru_3a1300 | External valve view. Species distinguished by the pair of rows of densely packed pores on each side of the raised ray. |
Centric Radial | Asterolampra vulgaris (E) | oamaru_3a5000 | Detail of external valve view. Pair of densely packed rows of pores on each side of raised ray. Rimportula visible at base of eroded ray hole. |
Centric Radial | Asterolampra vulgaris (E) | oamaru_3atilt1500 | External valve view tilted. |
Centric Radial | Asterolampra vulgaris (E) | oamaru_3atilt3000 | External valve view detail. Two eroded ray holes each with rimoportula at its bottom lip. |
Centric Radial | Stictodiscus californicus var. nitida | oamaru_3btilt1800 | External valve view. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3c450 | External valve view. Distinctive central rosette and two parallel rows of areolae along the furrows leading to the rimoportulae. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3c1500 | Detail of image oamaru_3c450. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3ctilt500 | External valve view. Distinctive central rosette and two parallel rows of areolae along the furrows leading to the rimoportulae. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3ctilt1500 | External view of valve margin. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3ctilt2500 | Detail of external opening of a rimoportula. |
Centric Radial | Aulacodiscus sollittianus var. novaezealandica | oamaru_3d1tilt900 | External valve view tilted. Distinguishing features of this species include (a) angular areolae covering surface of valve (cribra, which usually occlude areolae in this genus, appear to have eroded); (b) distal ends of rimoportulae broadly rounded; (c) collar visible at junction of mantle and valvocopula; (d) valvocopula with vertical rows of small areolae. |
Centric Radial | Aulacodiscus sollittianus var. novaezealandica | oamaru_3d1tilt1800 | Detail of image oamaru_3d1tilt900 showing areolae, rimoportula, mantle collar, and valvocopula. |
Centric Radial | Aulacodiscus sollittianus var. novaezealandica | oamaru_3d800 | External valve view. Distinguishing features of this species include (a) angular areolae covering surface of valve (cribra, which usually occlude areolae in this genus, appear to have eroded); (b) distal ends of rimoportulae broadly rounded; (c) collar visible at junction of mantle and valvocopula; (d) valvocopula with vertical rows of small areolae. |
Centric Radial | Aulacodiscus sollittianus var. novaezealandica | oamaru_3d1800 | Detail of areolae on valve face, distal end of a rimoportula, and valvocopula below the mantle rim. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3e450 | External view of valve with two broken rimoportulae. Distinctive central rosette and two parallel rows of areolae along the furrows leading to the rimoportulae. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3e4000 | Detail of broken rimoportula. |
Centric Polar | Kittonia elaborata | oamaru_3f1300 | View of external process (a type of ocellus). |
Centric Polar | Kittonia elaborata | oamaru_3f2000 | View of external openings of central rimoportulae. |
Centric Polar | Kittonia elaborata | oamaru_3f3000 | View of external process (a type of ocellus). |
Centric Polar | Kittonia elaborata | oamaru_3ff1300 | View of external process (a type of ocellus). |
Centric Polar | Kittonia elaborata | oamaru_3fffftilt500 | Whole valve. |
Centric Polar | Kittonia elaborata | oamaru_3ffftilt500 | Whole valve. |
Centric Polar | Kittonia elaborata | oamaru_3fftilt900 | Magnification of whole valve. |
Centric Polar | Kittonia elaborata | oamaru_3ftilt500 | Whole valve. |
Centric Polar | Kittonia elaborata | oamaru_3ftilt900 | Magnification of whole valve. |
Centric Polar | Kittonia elaborata | oamaru_3ftilt2500 | View of external openings of central rimoportulae. |
Centric Radial | Asterolampra insignis (E) | oamaru_3g1000 | External view of valve. Diameter 93 µm. Raised rays lie between blocks of areoale. Species distinguished by trapezoidal blocks of areolae at the margin between the rays. |
Centric Radial | Asterolampra insignis (E) | oamaru_3g2000 | External view of central area. |
Centric Radial | Asterolampra insignis (E) | oamaru_3g3500 | External view of valve margin. |
Centric Radial | Asterolampra insignis (E) | oamaru_3gtilt1100 | External valve view tilted. Illustrates ray holes with tiny rimoportula at the base of each ray hole. |
Centric Radial | Asterolampra insignis (E) | oamaru_3gtilt3500 | Detail of external view of valve margin. Illustrates eroded ray holes with tiny rimoportula at the base of each ray hole. |
Centric Polar | Triceratium secedens | oamaru_3htilt350 | External view. Convex sides separate this from T. pantocsekii. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3i500 | Internal view of valve. Distinctive ring around central area and pair of parallel rows of areolae along the rays leading to the rimoportulae. Internal openings of rimoportulae visible. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3i4000 | Internal view of valve edge showing opening of a marginal rimoportula. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3itilt4000 | Internal view of valve edge tilted showing opening of a marginal rimoportula. |
Centric Radial | Aulacodiscus cellulosus | oamaru_3itilt4500 | Internal view of valve edge tilted showing opening of a marginal rimoportula. Also visible in some of the areolae are cribra covering the exterior side. |
Centric Radial | Aulacodiscus janischii | oamaru_3j200 | External view of valve. Diameter 354 µm.Distinguished by (a) tangentially undulating valve surface, (b) small hyaline area in the center, (c) small areolae of nearly uniform size covering the valve, (d) lack of ribs showing in SEM, (e) uniform spacing of the striae (slightly wider on the crests), (f) rimoportulae near the margin protruding from the crests. |
Centric Radial | Aulacodiscus janischii | oamaru_3j700 | External view of valve edge showing opening of two marginal rimoportulae. |
Centric Radial | Aulacodiscus janischii | oamaru_3j1800 | External view of valve edge showing opening of a marginal rimoportulae. |
Centric Radial | Aulacodiscus janischii | oamaru_3jjtilt300 | External view of valve tilted. Distinguished by (a) tangentially undulating valve surface, (b) small hyaline area in the center, (c) small areolae of nearly uniform size covering the valve, (d) lack of ribs showing in SEM, (e) uniform spacing of the striae (slightly wider on the crests), (f) rimoportulae near the margin protruding from the crests. |
Centric Radial | Aulacodiscus janischii | oamaru_3jtilt1500 | External view of valve edge showing opening of a marginal rimoportulae. |
Centric Radial | Aulacodiscus janischii | oamaru_3jtilt1800 | External view of valve edge showing opening of a marginal rimoportulae. |
Centric Polar | Sheshukovia castellifera | oamaru_3k1500 | Single valve. Girdle view. |
Centric Polar | Sheshukovia castellifera | oamaru_3ktilt1800 | Single valve. Girdle view. |
Centric Radial | Aulacodiscus amoenus | oamaru_3l450 | External view. Valve convex in center, rising suddenly to a marginal ridge with rimoportulae protruding away from center on marginal side of the ridge. |
Centric Radial | Aulacodiscus amoenus | oamaru_3l1800 | Detail of external margin with rimoportula. |
Centric Radial | Aulacodiscus amoenus | oamaru_3ltilt500 | External view tilted. Valve convex in center, rising suddenly to a marginal ridge with rimoportulae protruding away from center on marginal side of the ridge. |
Centric Radial | Aulacodiscus amoenus | oamaru_3ltilt1800 | Detail of external margin with rimoportula. |
Centric Radial | Aulacodiscus amoenus | oamaru_3ltilt2000 | Detail of external margin with rimoportula. |
Centric Polar | Kittonia elaborata | oamaru_3mtilt1300 | Internal view of rimoportulae in central area. |
Centric Radial | Aulacodiscus janischii | oamaru_3n2500 | Detail of internal view of margin and inner opening of a rimoportula. |
Centric Radial | Aulacodiscus janischii | oamaru_3ntilt2500 | Detail of internal view tilted of margin and outer opening of a rimoportula in image oamaru_3n2500. |
Centric Radial | Aulacodiscus sollittianus var. novaezealandica | oamaru_3ootilt1500 | Detail of rimoportula in image oamaru_3otilt500. Faint lines at edge of some areolae may be remainder of cribra. |
Centric Radial | Aulacodiscus sollittianus var. novaezealandica | oamaru_3otilt500 | External valve view tilted. Distinguishing features of this species include (a) angular areolae covering surface of valve (cribra, which usually occlude areolae in this genus, appear to have eroded); (b) distal ends of rimoportulae broadly rounded; (c) collar visible at junction of mantle and valvocopula; (d) valvocopula with vertical rows of small areolae. |
Centric Radial | Aulacodiscus sollittianus var. novaezealandica | oamaru_3otilt1500 | Detail of external view clearly showing the base of the rimoportula. The concoidal fractures on flange at the mantle edge suggest broken glass. |
Centric Polar | Sheshukovia castellifera | oamaru_3ptilt1100 | Single valve. Tilted view. |
Centric Radial | Ellerbeckia clavigera | oamaru_3qtilt1800 | Internal view of two sibling linking valves. Diameter 44 µm. See image oamaru_3qtilt5000 for detail view. For an external view, see Ellerbeckia clavigera image oamaru3qtilt1300. |
Centric Radial | Ellerbeckia clavigera | oamaru_3qtilt5000 | Magnified image of oamaru_3qtilt1800. Exterior of mantles of two sibling linking valves. Top valve is the intaglio valve. Bottom valve is the cameo valve with the step appearing as the light line two or three pores below the links. The black marks are spaces in the interlocking ridges and grooves. Image width 23 µm. |
Centric Radial | Endictya oceanica | oamaru_3rtilt500 | External view. Valve center has a few projections intact but many appear to be crushed; valve rim has narrow flange and line of pores. See also internal view of an Endictya in this collection. Witkowski et al. (2017) figs 145-146 does not appear to have enough detail to distinguish Pyxilla from Endictya. |
Centric Polar | Triceratium castellatum var. fractum | oamaru_3s700 | External view of valve with raised porefields on the poles. |
Centric Polar | Triceratium castellatum var. fractum | oamaru_3s1500 | Detail of a raised porefield at a pole. |
Centric Polar | Triceratium castellatum var. fractum | oamaru_3stilt700 | External view of valve with raised porefields on the poles. |
Centric Polar | Kittonia elaborata | oamaru_3ttilt2500 | External openings of central rimoportulae in magnified view of image oamaru_3tttilt600. |
Centric Polar | Kittonia elaborata | oamaru_3tttilt600 | Whole valve with fractured processes. |
Centric Polar | Kittonia elaborata | oamaru_3tttilt2500 | Fractured ocellus in magnified view of image oamaru_3tttilt600. |
Centric Polar | Kittonia elaborata | oamaru_3tttilt4000 | External opening of fractured stem of process in magnified view of image oamaru_3tttilt600. |
Centric Polar | Rutilaria radiata | oamaru2a1000 | External view of valve of a long form. Length 123 µm. Ocellus at one end is eroded. The opposite ocellus is missing. The twisted periplekton (a specialized rimoportula) arises from the center. |
Centric Polar | Rutilaria radiata | oamaru2a4000 | Detail of external view of periplekton of image oamaru2a1000. Erosion in two locations has exposed the hollow interior. |
Centric Polar | Rutilaria radiata | oamaru2aatilt1000 | External view of valve tilted. Ocellus at one end is eroded. The opposite ocellus is missing. The twisted periplekton (a specialized rimoportula) arises from the center. |
Centric Polar | Rutilaria radiata | oamaru2atilt1000 | External view of valve tilted. Ocellus at one end is eroded. The opposite ocellus is missing. The twisted periplekton (a specialized rimoportula) arises from the center. |
Centric Polar | Rutilaria radiata | oamaru2atilt2000 | Detail of periplekton. Erosion has exposed the hollow interior. |
Centric Polar | Rutilaria radiata | oamaru2atilt4000 | Detail of periplekton. Erosion has exposed the hollow interior. |
Centric Polar | Rutilaria radiata | oamaru2atilt5000 | Detail of marginal spines. |
Centric Radial | Endictya sp1 | oamaru2btilt1600 | Internal view. Areolae on mantle variable in size (in contrast to Endictya oceanica). Internal apertures of rimoportulae at angle of mantle and face. Internal pores arranged in rows radiating from valve center (similar to Melosira and Stephanopyxis). |
Centric Polar | Entogoniopsis venosa | oamaru2ctilt1000 | Pseudocelli raised on elevations and have a plain rim. Areolae large near center, smaller beneath elevations. Mantles distinct and vertical. See images oamaru21100 and oamaru22000 for other views of this specimen. |
Centric Polar | Rutilaria radiata | oamaru2d1500 | External valve view of a short form. Length 73 µm. Both ocelli, eroded, are visible at the poles. In the center, a fragment of the sibling valve shows the internal opening of the periplekton. |
Centric Polar | Rutilaria radiata | oamaru2d5000 | Detail of eroded ocellus of image oamaru2d1500. |
Centric Polar | Rutilaria radiata | oamaru2dtilt_1500 | External valve view of a short form, tilted. Length 73 µm. Both ocelli, eroded, are visible at the poles. In the center, a fragment of the sibling valve shows the internal opening of the periplekton. |
Centric Polar | Rutilaria radiata | oamaru2dtilt_1800 | External valve view of a short form, tilted. Length 73 µm. Both ocelli, eroded, are visible at the poles. In the center, a fragment of the sibling valve shows the internal opening of the periplekton. |
Centric Radial | Brightwellia coronata | oamaru2etilt_3500 | External view of areolae and ring of ovals. More eroded than other Brightwellia specimens here. |
Centric Radial | Asterolampra insignis (I) | oamaru2ftilt_1000 | Internal valve view. |
Centric Radial | Stephanopyxis sp1 | oamaru2gtilt_1500 | Two sibling valves joined by the valve faces. Internal openings to rimoportulae visible on the top valve. |
Centric Radial | Arachnoidiscus oamaruensis | oamaru2htilt_1100 | External view of tilted valve. Diameter 95 µm. Species epithet oamaruensis was chosen by (1) key in Brown 1933, lead 17: primary rays slender, penetrating to the fourth, third, or second circle of areolae; and (2) the central area in this SEM which could be intepreted as hyaline, matching image in Charles 2017 and Brown 1933. |
Biraphid Symmetrical | Gyrosigma sp1 | oamaru2i700gyrosigma | Internal view. Length = 184 µm. It might be surprising to see a diatom associated with mud flats in this collection. This specimen might be an indicator of the volcanic shoals that occassionally formed in the basin where the sediments were accumulating. |
Biraphid Symmetrical | Gyrosigma sp1 | oamaru2i4500 | Internal view. Central area with proximal raphe ends. |
Biraphid Symmetrical | Gyrosigma sp1 | oamaru2ii4500 | Internal view. Apex with distal raphe ending in a helictoglossa. |
Centric Radial | Hyalodiscus laevis | oamaru2j600 | External view of valve. Diameter 112 µm. |
Centric Radial | Hyalodiscus laevis | oamaru2jtilt800 | External view of valve tilted. Diameter 112 µm. |
Centric Radial | Hyalodiscus laevis | oamaru2jtilt1800 | Detail of valve margin. |
Centric Polar | Trinacria excavata | oamaru2ktilt1100 | Genus distinguished by valves with 3 or 4 poles elevated at the corners. Elevations have spines which interlock neatly with the corresponding poles on adjacent cells. |
Centric Polar | Trinacria excavata | oamaru2ktilt4500 | Detail of image oamaru2ktilt1100. Corner eroded. Linking spines visible. |
Centric Polar | Trinacria excavata | oamaru2ktilt5000 | Detail of image oamaru2ktilt1100. Linking spines clearly visible. |
Centric Radial | Asterolampra vulgaris (E) | oamaru2ltilt1500 | External valve view. |
Centric Polar | Hemiaulus sp1 | oamaru2mtilt1800 | Girdle view of valve tilted. |
Centric Polar | Pyxilla prolungata | oamaru2ntilt1000 | Tilted view of a valve. |
Centric Polar | Williamriedelia tenuicornis | oamaru2otilt1500 | Girdle view of complete valve. May also be placed in Riedelia. |
Centric Radial | Podosira corolla | oamaru2ptilt1800 | External view of valve tilted. These specimens look nothing like the images for Podosira in Round et al. Perhaps it is a different genus. Schmidt calls this P. corolla and D&S and DiatomBase use Schmidt as the source. Charles calls it P. corolla on the index but P. coronata on the image. Charles has an excellent LM image. |
Centric Radial | Brightwellia coronata | oamaru2ptilt3500 | Detail of external view of ring of ovals. Four of the ovals demonstrate the chamber beneath the oval and the corresponding single, round foramen leading to the cell interior. |
Centric Radial | Podosira corolla | oamaru2qtilt1500 | External view of valve tilted. These specimens look nothing like the images for Podosira in Round et al. Perhaps it is a different genus. Schmidt calls this P. corolla and D&S and DiatomBase use Schmidt as the source. Charles calls it P. corolla on the index but P. coronata on the image. Charles has an excellent LM image. |
Centric Radial | Cestodiscus spinifer | oamaru2r700 | Internal view. Diameter = 106 µm. Distinguished from Arachnoidiscus by having no central ring with attached flange. |
Centric Polar | Triceratium pulvinar | oamaru2s800 | Internal view of valve. Rows of pores clustered and radiating from center of valve. Distance between adjacent apices at top of image 100 µm. Compare to T. unguiculatum. |
Centric Polar | Triceratium pulvinar | oamaru2s3000 | Detail of internal view of an apex. Rows of pores clustered and radiating from center of valve. Compare to T. unguiculatum. |
Centric Polar | Hemiaulus sp1 | oamaru2t1500 | Girdle view of valve. |
Centric Radial | Podosira corolla | oamaru2t4500 | Detail of junction between valve face and mantle showing rimoportulae and striated band. |
Centric Polar | Entogoniopsis pseudonervata | oamaru2utilt1000 | Pseudocelli on the poles have no rim. Mantles distinct and vertical. |
Centric Radial | Cestodiscus spinifer | oamaru2v1300 | External view. Diameter = 63 µm. Distinguished from Arachnoidiscus by having no central ring with attached flange. |
Centric Radial | Cestodiscus spinifer | oamaru2wtilt1500 | Internal view. Tilted view of oamaru2ww1300. Diameter = 58 µm. Distinguished from Arachnoidiscus by having no central ring with attached flange. |
Centric Radial | Cestodiscus spinifer | oamaru2ww1300 | Internal view. Diameter = 58 µm. Distinguished from Arachnoidiscus by having no central ring with attached flange. |
Centric Polar | Triceratium favus var. quadrata | oamaru2x900 | Internal view of valve. Clustered pores radiate from the center. |
Centric Polar | Triceratium favus var. quadrata | oamaru2xtilt500 | External view of valve tilted. |
Centric Polar | Triceratium favus var. quadrata | oamaru2xtilt800 | Internal view of valve tilted. |
Centric Polar | Triceratium favus var. quadrata | oamaru2xtilt2500 | Detail of internal view of apex. |
Centric Polar | Triceratium favus var. quadrata | oamaru2xxtilt2500 | Internal view of an ocellus at an apex. |
Centric Radial | Aulacodiscus cellulosus | oamaru3_a350 | Internal view of valve. Distinctive ring around central area and pair of parallel rows of areolae along the rays leading to the rimoportulae. Internal openings of rimoportulae eroded in the same direction. |
Centric Radial | Aulacodiscus cellulosus | oamaru3_a3000 | Detail of internal view of eroded rimoportula. |
Centric Radial | Aulacodiscus cellulosus | oamaru3_atilt450 | Internal view of valve tilted. Distinctive ring around central area and pair of parallel rows of areolae along the rays leading to the rimoportulae. Internal openings of rimoportulae eroded in the same direction. |
Centric Radial | Asterolampra insignis (I) | oamaru3_b1800 | Detail of internal view of central area. |
Centric Radial | Asterolampra insignis (I) | oamaru3_btilt1100 | Internal valve view. |
Centric Radial | Asterolampra vulgaris (I) | oamaru3_c1300 | Internal view of valve. Visible are long ray chambers and short chambers on either side. |
Centric Radial | Asterolampra vulgaris (I) | oamaru3_c2000 | Detail of internal view of valve. The short parallel chambers show pores in the external side. At end of each ray chamber is the internal opening of a rimoportula. |
Centric Radial | Asterolampra vulgaris (I) | oamaru3_c3500 | Detail of internal view of central area. |
Centric Radial | Asterolampra vulgaris (I) | oamaru3_ctilt1300 | Internal view of valve tilted. Visible are ray chambers with ray holes at the distal ends and a cross section of the valve edge. |
Centric Radial | Asterolampra vulgaris (I) | oamaru3_d800 | Internal view of the valve. |
Centric Radial | Asterolampra vulgaris (E) | oamaru3_d24500 | Detail of valve edge. Visible are rows of dense pores, ray holes, and rimoportulae at base of ray holes. |
Centric Radial | Aulacodiscus aemulans | oamaru3_de3000 | Detail of external valve edge. Cribra with a daisy shape cover the areolae. One rimoportula stem visible. |
Centric Radial | Aulacodiscus aemulans | oamaru3_e7000 | Cribra with a daisy shape cover the areolae. |
Centric Radial | Aulacodiscus aemulans | oamaru3_etilt600 | External view of valve. Cribra with a daisy shape cover the areolae. |
Centric Radial | Aulacodiscus aemulans | oamaru3_etilt2000 | Cribra with a daisy shape cover the areolae. |
Centric Radial | Stictodiscus novaezealandiae | oamaru3_ftilt600 | Internal view of valve. Distance between apices across center 163 µm. |
Centric Radial | Stictodiscus novaezealandiae | oamaru3_ftilt3000 | Internal view of an apex. |
Centric Radial | Stictodiscus novaezealandiae | oamaru3_ftilt4000 | Internal view of rimoportulae in central area. |
Centric Radial | Aulacodiscus janischii | oamaru3_g200 | Internal view of valve. |
Centric Radial | Aulacodiscus janischii | oamaru3_gtilt250 | Internal view of valve tilted. |
Centric Radial | Aulacodiscus janischii | oamaru3_gtilt1500 | Internal view of opening of rimoportula. |
Centric Radial | Aulacodiscus janischii | oamaru3_gtilt1800 | External view of rimoportula. |
Centric Polar | Triceratium castellatum var. fractum | oamaru3_h800 | Internal view of valve. |
Centric Polar | Goniothecium decoratum | oamaru3_i1500 | Girdle view of two cells linked by teeth. |
Centric Polar | Trinacria ventricosa | oamaru3_j900 | Internal valve view. |
Centric Polar | Trinacria ventricosa | oamaru3_j3500 | Internal view of a pole. |
Centric Polar | Trigonium glandiferum | oamaru3_k700 | Internal view. Heavy internal costae, a septum in each corner, and internal openings of the scattered rimoportulae on the central area of the valve face. |
Centric Polar | Trigonium glandiferum | oamaru3_k1300 | Internal view. Detail of image oamaru3_k700. Heavy internal costae and internal openings of the scattered rimoportulae on the central area of the valve face. |
Centric Polar | Hemiaulus sp1 | oamaru3_l1300 | Girdle view of valve. |
Centric Polar | Triceratium favus var. quadrata | oamaru3a600 | External view of valve. |
Centric Polar | Triceratium favus var. quadrata | oamaru3atilt600 | External view of valve. |
Centric Polar | Triceratium favus var. quadrata | oamaru3atilt2500 | Detail of external view of ocellus. |
Centric Radial | Asterolampra insignis (I) | oamaru3b1100 | Internal view of eroded valve. |
Centric Radial | Asterolampra insignis (I) | oamaru3btilt1100 | Internal view of eroded valve tilted. Shows thickness of valve wall. |
Centric Radial | Asterolampra vulgaris (E) | oamaru3c1100 | External valve view. Species distinguished by the pair of rows of densely packed pores on each side of the raised ray. |
Centric Radial | Asterolampra vulgaris (E) | oamaru3c3500 | Detail of external view of central area. |
Centric Radial | Asterolampra vulgaris (E) | oamaru3c4500 | Detail of external margin. |
Centric Radial | Asterolampra vulgaris (E) | oamaru3ctilt1500 | External valve view. Species distinguished by the pair of rows of densely packed pores on each side of the raised ray. |
Centric Radial | Asterolampra vulgaris (E) | oamaru3ctilt6000 | Detail of external margin. |
Centric Radial | Asterolampra vulgaris (E) | oamaru3dtilt4000 | External valve view tilted. |
Centric Radial | Asterolampra vulgaris (I) | oamaru3e1100 | Internal view of valve. |
Centric Radial | Asterolampra vulgaris (I) | oamaru3e3000 | Detail of internal view of ray chambers and parallel side chambers with external pores visible. |
Centric Radial | Asterolampra vulgaris (I) | oamaru3e6000 | Detail of internal view of ray chambers and parallel side chambers with external pores visible. |
Centric Radial | Asterolampra vulgaris (I) | oamaru3ee3000 | Detail of internal view of central area. |
Centric Radial | Asterolampra vulgaris (I) | oamaru3etilt1500 | Internal view of valve tilted. Cross section of valve wall visible. |
Centric Radial | Stictodiscus splendidus | oamaru3f400 | External view. Distance between apices 208 µm! Pore fields at apices. Very clear example of the raised thickenings surrounding the areolae that define the genus. This specimen defies the category of a Centric Radial diatom. |
Centric Radial | Stictodiscus splendidus | oamaru3ftilt2000 | External view of apical pore field. Width of image 58 µm. Very clear example of raised thickenings surrounding the areolae that define the genus. |
Centric Radial | Stephanopyxis sp2 | oamaru3g900 | External view of valve of a domed form. |
Centric Radial | Stephanopyxis sp3 | oamaru3g1500 | External view of form with nearly flat valve. |
Centric Radial | Coscinodiscus subdivicus | oamaru3h1500 | External view of valve. Radial lines of large areolae lead to the rimoportulae near margin. The marginal rimoportulae suggest an Aulacodiscus. |
Centric Radial | Aulacodiscus aemulans | oamaru3i1000 | External view of valve. Cribra with a daisy shape cover the areolae. Some cribra have eroded showing the areolae. |
Centric Radial | Aulacodiscus aemulans | oamaru3i4500 | Detail of image oamaru3i1000. |
Centric Radial | Aulacodiscus aemulans | oamaru3itilt1100 | External view of valve tilted. Cribra with a daisy shape cover the areolae. Tubes of rimoportulae form a ring near the margin. |
Centric Radial | Aulacodiscus aemulans | oamaru3itilt3000 | Detail of image oamaru3itilt1100. Areola diameter ~ 2.5 µm. Diameter of pore in cribra ~ 0.4 µm. Rimoportula external opening ~ 1.9 µm. |
Centric Radial | Ellerbeckia clavigera | oamaru3itilt3500 | External view of both mantles of image oamaru3vtilt1000. |
Centric Radial | Ellerbeckia clavigera | oamaru3itilt6000 | Internal view of mantle of intaglio valve of image oamaru3vtilt1000. |
Centric Radial | Stephanopyxis sp2 | oamaru3jtilt1000 | External view of valve tilted of a domed form. |
Centric Radial | Podosira corolla | oamaru3ktilt2000 | External view of valve tilted. These specimens look nothing like the images for Podosira in Round et al. Perhaps it is a different genus. Schmidt calls this P. corolla and D&S and DiatomBase use Schmidt as the source. Charles calls it P. corolla on the index but P. coronata on the image. Charles has an excellent LM image. |
Centric Radial | Podosira corolla | oamaru3ktilt5000 | Detail of external view of valve edge. Rimoportulae protrude through the striated band. The mantle is below the flange at the junction of face and mantle. |
Centric Radial | Stephanopyxis sp3 | oamaru3ltilt1800 | External view of form tilted with nearly flat valve. |
Centric Radial | Ellerbeckia sp1 | oamaru3mtilt1000 | Two linking valve faces, the only preserved parts of these valves. Diameter 106 µm. External view of the bottom valve and internal view of the upper valve. The fine rays around the upper valve are cross-sections of mantle areolae. The hollowed rim of the upper valve was caused by erosion of the valve. The ring of narrow uprights on the lower valve are costae on the valve face visible from the side. They are interlocking with the corresponding costae on the upper valve face. |
Centric Radial | Ellerbeckia sp1 | oamaru3mtilt4000 | Detail of valve mantles. Image width 29 µm. Two linking valve faces. External view of the bottom valve and internal view of the upper valve. The fine rays around the upper valve are cross-sections of mantle areolae. The hollowed rim of the upper valve was caused by erosion of the valve. The ring of narrow uprights on the lower valve are costae on the valve face visible from the side. They are interlocking with the corresponding costae on the upper valve face. |
Centric Radial | Stephanopyxis sp4 | oamaru3ntilt1800 | External view of a form with hemispheric valve. |
Centric Radial | Podosira corolla | oamaru3otilt1800 | Wide striated band below the flange. External view of valve tilted. These specimens look nothing like the images for Podosira in Round et al. Perhaps it is a different genus. Schmidt calls this P. corolla and D&S and DiatomBase use Schmidt as the source. Charles calls it P. corolla on the index but P. coronata on the image. Charles has an excellent LM image. |
Centric Radial | Ellerbeckia clavigera | oamaru3qtilt1300 | External view of linking valve. The wavy rim suggests the linking area of Ellerbeckia clavigera in image oamaru_3qtilt1800 which shows two sibling valves linked. Diameter 71 µm. Round et al. (1990) has an SEM image very similar to this specimen. |
Centric Radial | Coscinodiscus subdivicus | oamaru3rtilt1800 | External view of valve tilted. Radial lines of large areolae lead to the rimoportulae near margin. The marginal rimoportulae suggest an Aulacodiscus. |
Centric Polar | Triceratium pantocsekii | oamaru3stilt700 | External view. Straight sides separate this from T. secedens. |
Centric Radial | Coscinodiscus argus | oamaru3stilt1000 | Valve diameter 97 µm. Areola diameter ~ 2.2 µm. Areolae on a radius 11-12. By comparison, Coscinodiscus asteroides appears to have denser areolae arranged in more distinct rows and has a more definite central area in Charles and in Heck. Edwards shows a distribution of areolae similar to this specimen. |
Centric Radial | Strangulonema barbadense | oamaru3stilt1100 | External view of valve face with collar at edge giving rise to spines. Round et al. (1990) has these spines as flattened and furcate (forked) though they are not here. Only this one species has been described. |
Centric Polar | Rattrayella oamaruensis | oamaru3t1500 | External view. Large openings around the valve margin are ocelli with the coverings of small porelli eroded. Valve diameter = 52 µm. Ocelli diameter = 4 µm. Rimoportulae between the ocelli distinguish this from Glyphodiscus. |
Centric Polar | Rattrayella oamaruensis | oamaru3t7000 | External view of an ocellus with covering of small porelli eroded. Ocellus diameter = 4 µm. |
Centric Polar | Rattrayella oamaruensis | oamaru3ttilt1500 | External view. Large openings around the valve margin are ocelli with the coverings of small porelli eroded. Valve diameter = 52 µm. Ocelli diameter = 4 µm. Rimoportulae between the ocelli distinguish this from Glyphodiscus. |
Centric Polar | Rattrayella oamaruensis | oamaru3ttilt3500 | External view of valve margin with ocelli and rimoportulae. Large openings along the margin are ocelli with the coverings of small porelli eroded. Remnants of the coverings visible around inner edge of an ocellus. Ocellus diameter 4 µm. Rimoportulae between the ocelli distinguish this from Glyphodiscus. |
Centric Radial | Brightwellia coronata | oamaru3u1100 | External view of central area. |
Centric Radial | Ellerbeckia clavigera | oamaru3vtilt1000 | Linking valves of two sibling cells. Intaglio valve (internal view) at the top, cameo valve with the step in the mantle at the bottom. The wavy pattern of the ridges and grooves where the cells join matches the pattern in image oamaru3qtilt1300. |
Centric Polar | Entogoniopsis venosa | oamaru21100 | Tilted view of image oamaru2ctilt1000. Pseudocelli raised on elevations and have a plain rim. Areolae large near center, smaller beneath elevations. Mantles distinct and vertical. |
Centric Polar | Entogoniopsis venosa | oamaru22000 | Magnified view of oamaru21100. Pseudocelli raised on elevations and have a plain rim. Areolae large near center, smaller beneath elevations. Mantles distinct and vertical. |