Jullienula ortmanni ( Silén, 1941 )

Martino, Emanuela Di, 2023, Scanning electron microscopy study of Lars Silén’s cheilostome bryozoan type specimens in the historical collections of natural history museums in Sweden, Zootaxa 5379 (1), pp. 1-106 : 58-59

Jullienula ortmanni ( Silén, 1941)

( Fig. 30 ; Table 28)

Figularia? ortmanni Silén, 1941: 120 , fig. 181.

Jullienula ortmanni : Yang et al., 2018: 225.

Material examined. Holotype by original designation UPSZTY 191144 A and, on the same substrate (i.e. scaphopod shell), paratype UPSZTY 191144 B, Okinose , Sagami, Japan; depth 600 m. Leg. Prof. S. Bock 1914.

Description. Colony encrusting, multiserial, unilaminar ( Fig. 30A ).

Ancestrula tatiform with oval outline (435–440 × 300–330 µm) and at least 17 spines surrounding the pear-shaped opesia (355–395 × 230 µm); spines variably spaced, 20–25 µm in diameter at the base, those preserved 140–145 µm long overarching the frontal membrane, lodged on a smooth, narrow gymnocyst (30–75 µm wide), steeply sloping towards the substrate ( Fig. 30D ); one smaller (360–390 × 270–275 µm) and two larger (430–470 × 295–330 µm) autozooids budded distally and distolaterally from the ancestrula, respectively.

Autozooids rounded-hexagonal to oval, longer than wide (mean L/ W 1.38), distinct, separated by deep grooves ( Fig. 30A ); frontal shield costate, consisting of 14–21 (more commonly 16) costae, 40–80 µm wide proximally, originating at zooidal margin; costae meeting along an undulate median suture line, triangular except for the distalmost pair more parallel-sided and forming the proximal margin of the orifice and its lateral indentations; adjacent costae separated by numerous (up to 10) slit-like lacunae, 10–15 µm long; a single, minute, circular (10–15 µm in diameter), costal pseudopore observed in the majority of costae at the inner tip ( Fig. 30B ).

Orifice dimorphic: bell-shaped with straight or slightly convex proximal margin and blunt condyles in autozooids; slightly shorter and wider, and more trifoliate because of a more convex proximal margin and stouter condyles in ovicellate zooids ( Fig. 30B, C ).

Ovicells cap-like, kenozooidal; ooecium smooth, imperforate ( Fig. 30A, B ).

The single kenozooid observed 210 µm long by 370 µm wide, irregularly polygonal with the frontal entirely occupied by the costate shield formed of eight costae and lacking an opening ( Fig. 30D , see asterisk). Avicularia seemingly absent.

Remarks. Silén (1941) tentatively placed this species in Figularia , aware that the structure of the costal shield and of the ooecium differed from typical Figularia species. As several other doubtful species of Figularia (see López-Gappa et al. 2021; Rosso et al. 2021), F.? ortmanni was first transferred to Cribrilina Gray, 1848 (e.g. Hirose 2010), and subsequently moved to Jullienula ( Yang et al. 2018) , which seems indeed the best fit.

Yang et al. (2018) reported the absence of costal and ooecial pseudopores as the main difference between this species and other species of Jullienula , such as J. hippocrepis and J. erinae . While the absence of ooecial pores is here confirmed, a minute costal pseudopore was observed in most costae (e.g. Fig. 30B , see arrows).

Ancestrulae were observed and measured from the two paratypes, both young colonies consisting of 10 (plus a kenozooid) and 15 autozooids, respectively.

Recent molecular sequences place the type species of Jullienula , J. hippocrepis ( Hincks, 1882) , as sister clade of Valdemunitella and Klugeflustra (Cuevas et al. in preparation), suggesting that despite having true costae Jullienula is not a cribrilinid and should be transferred to the Calloporidae , analogously to Membraniporella nitida ( Johnston, 1838) (see Lidgard et al. 2012), or species of Valdemunitella (i.e. V. huttoni and V. spinea ) formerly included in the cribrilinid genus Figularia ( Brown 1952; Gordon 1984, 1986; López-Gappa et al. 2021).

Figures

FIGURE 30. Jullienula ortmanni (Silén, 1941). A–C. Holotype UPSZTY 191144A, Japan.A. Group of autozooids. B. Close-up of two ovicellate zooids.Arrows indicate costal pseudopores. C. Close-up of the orifice. D. Paratype UPSZTY 191144B, Japan. Portion of a young colony showing the ancestrula with the first budded zooids and a kenozooid (see asterisk). Scale bars: A, D = 200 µm; B = 100 µm; C = 40 µm.