DICTYOPSELLIDAE Brönnimann, Zaninetti & Whittaker 1983

Simmons, Michael, Bidgood, Michael, Consorti, Lorenzo & Schlagintweit, Felix, 2025, A Review Of The Identity And Biostratigraphy Of Cenomanian “ Larger ” Benthic Foraminifera: Part 2 - The Order Loftusiida (Excluding The Suborder Orbitolinina), Acta Palaeontologica Romaniae 21 (1), pp. 103-192 : 164-165

Family DICTYOPSELLIDAE Brönnimann, Zaninetti & Whittaker 1983 (diagnosis sensu Loeblich & Tappan, 1987)

Genera Dictyopsella Munier-Chalmas 1900 and

Conorbinella Poroshina 1976 (see Table 1 for diagnosis)

Unlike other genera discussed above, these two genera are discussed together in this section because of a rather convoluted suprageneric taxonomic history. The genus Dictyopsella ( type species Dictyopsella kiliani Munier-Chalmas in Schlumberger, 1900), with or without its subfamily the Dictyopsellinae which would include Conorbinella ( type species Conorbinella azerbaidjanica Poroshina, 1976 ), has had a varied history with regard to its higher classification, being placed at different times by different authors in the Trochamminidae , the Barkerinidae , the Ataxophragmiidae , the Remaneicidae and the Dictyopsellidae , and to the superfamilies Orbitolinacea and Loftusiacea (see Loeblich & Tappan, 1985b, for a discussion on this topic). This was due primarily to its internal complexity not being well understood.

Loeblich & Tappan (1985b) transferred the Dictyopsellidae Brönnimann et al. (1983) to the superfamily Loftusiacea and included in it the genera Dictyopsella , Conorbinella and Dictyopselloides n. gen. However, they reverted the Dictyopsellidae family back to within the Ataxaophragmiacea (=Ataxophragmoidea) superfamily in their extensive 1987 treatment – though without an explicit explanation – and included a fourth genus in the family, Andamookia Ludbrook, 1966 . This position (within the order Loftusiida ) was maintained by Kaminski (2014) and the WoRMS foraminiferal database ( Hayward et al., 2025).

Dictyopsella is a low conical trochospiral genus which because of its complex internal structure was compared to the externally similar Coxites . However, the latter genus has an internal median plate which may bifurcate or digitate, whereas the former genus has many radiating radial partitions (beams) ( Loeblich & Tappan, 1985b, 1987).

It is the nature of subepidermal “network” or “mesh” (comprised of radial beams and cross-cutting rafters) that seems, morphologically, to distinguish Dictyopsella from the three other genera in the family (note age-ranges taken from Loeblich & Tappan, 1987):

Conorbinella : radial partitions (beams) only [Barremian-Aptian (but possibly as young as Cenomanian – see below)]

Dictyopselloides : radial partitions (beams) with a few incipient rafters in later chambers [Santonian-?Campanian]

Andamookia : radial partitions (beams) with a few transverse rafters [Aptian]

Dictyopsella : radial partitions (beams) as well as intercalary beams extending from the outer wall towards the centre, and shallow secondary cross-cutting partitions (rafters) projecting inwards from upper and lower chamber surfaces forming a full sub-epidermal network [Cenomanian-Maastrichtian]

In some examples of Dictyopsella , the “mesh- like” nature of the subepidermal network can obscure the radial nature of the beams near the test surface (see Loeblich & Tappan, 1985b, figs. 1-5 and Figure 27d below).

Figures

Fig. 27. Representative illustrations of Dictyopsella charentensis: a. Dorsal view (camera lucida drawing), Loeblich & Tappan (1985b, fig. 1, France); b. Umbilical view (SEM photograph), Loeblich & Tappan (1985b, pl. 1, fig. 10, France); c. Near equatorial section (deep cut), Loeblich & Tappan (1985b, pl. 2, fig. 8, France); d. Near equatorial section (shallow cut), Loeblich & Tappan (1985b, pl. 2, fig. 4, France).