Siphotrochammina sp.

Camacho, S, Moura, D, Connor, S, Scott, DB & Boski, T, 2015, Taxonomy, ecology and biogeographical trends of dominant benthic foraminifera species from an Atlantic-Mediterranean estuary (the Guadiana, southeast Portugal), Palaeontologia Electronica 52 (4), pp. 1-37 : 21

Siphotrochammina sp.

Figure 3.11-3.13

1995 Trochammnina inflata Montagu 1808 ; ‘Sipho’ type, Scott, Hasegawa, Saito, Ito and Collins, p. 294, figs. 6.11, 6.13-6.17.

Morphological description. Test a low trochospiral, chambers ovate, increasing gradually in size as added, sutures gently curved, periphery rounded; wall light brown in color, finely and sparsely agglutinated on a proteinaceous base, the early whorl darker brown and with very little agglutinated material; aperture interiomarginal, at the end of a siphon-like lobe projecting from the umbilical margin of the chamber and directed forward ( Loeblich and Tappan, 1987). Although not recognizable through binocular microscope observation, the SEM images of the two photographed specimens ( Figure 3.11 -12) exhibit a well defined, dorsal, inter-cameral foramen. As far as we know, this characteristic is not documented elsewhere and more photographs should be taken to confirm this morphological characteristic.

Occurrence. Common species in the modern estuary, with a well-defined position along the north-south gradient, appearing (live and dead) only in the northernmost samples (from Aouro upstream).

Figures

FIGURE 3. Scanning electron and light microscope micrographs of the foraminifera specimens. Scale bar equals 100 µm except where noted otherwhise; 1-2- Jadammina macrescens (Brady, 1870); 1- supplementary apertures view; 2- detail of supplementary apertures (scale bar = 50 µm); 3-4- Lepidodeuterammina plymouthensis Brönnimann and Whittaker, 1990; 3- dorsal view; 4- ventral view; 5-8- Lepidodeuterammina ochracea (Williamson, 1858); 5- dorsal view; 6- ventral view; 7- dorsal view of a smaller specimen; 8- ventral view of a smaller specimen; 9-10- Portatrochammina sp.; 9- dorsal view; 10- ventral view; 11-13- Siphotrochammina sp.; 11- dorsal side with inter-cameral foramen view; 12- dorsal view of a smaller specimen, also with inter-cameral foramen; 13- ventral view of a smaller specimen; 14-16- Tiphotrocha comprimata Saunders, 1957; 14- dorsal view; 15- ventral view; 16- individual strongly attached to a sea-grass leaf; detail of a Pinus pollen grain at the center of the leaf; 17-21- Trochammina inflata (Montagu, 1808); 17- dorsal view; 18- ventral view; 19- ventral view with umbilical tube detail; 20- microspheric form dorsal view; 21- microspheric form ventral view; 22- Eggerelloides scaber (Williamson, 1858); 23-25- Textularia earlandi Parker, 1952; 23- apertural view; 24- lateral view; 25- profile view with aperture in detail; 26-29- Discorinopsis aguayoi (Bermúdez, 1935); 26- scanning electron dorsal view; 27- scanning electron ventral view; 28- light microscope dorsal view; 29- light microscope ventral view.