Triphyllozoon indivisum Harmer, 1934

Asagabaldan, M. A., Bourgougnon, N., Bedoux, G., Kristiana, R., Ayuningrum, D., Widyananto, P. A., Muchlissin, S. I., Magueresse, A., Sabdono, A., Trianto, A. & Sa, O. K. Radja-, 2019, Some Cheilostomata (Bryozoa) from the Java Sea, central Indonesian Archipelago with a description of Pleurocodonellina jeparaensis n. sp. (Smittinidae), Zootaxa 4668 (3), pp. 329-342 : 338-339

Triphyllozoon indivisum Harmer, 1934

( Figs 2F , 7 A–C; Table 6)

Triphyllozoon indivisum Harmer, 1934: p. 614 , text-figs 25F, 40, pl. 35, figs 33, 34, pl. 40, figs 10–12. Hayward, 2000: p. 112, fig. 2d–e.

Material examined. KJBR 46, Stn KJ01-1; KJBR 47, KJBR 48, Stn KJ01-2; KJBR 49, Stn KJ01-3.

Description. Fragments flat, fan-shaped. Fenestrulae broadly oval ( Fig. 7A ), trabeculae mostly narrower, consisting of 3–4 longitudinal autozooidal series. Autozooids convex, oval to hexagonal at growing edge, separated by raised sutures. Frontal shield slightly nodular, with 4–6 marginal pores, these sometimes very large. Lateral condyles obscured by secondary calcification; rounded pseudospiramen (labial pore) medially placed below the orifice. Secondary calcification largely concealing the primary orifice. Avicularia of two types: the most characteristic is large, asymmetrical, proximal within fenestrula margins, the rostrum narrowed medially, larger distally and ending in two upcurved asymmetrical tips ( Fig. 7B , arrow); the other avicularium is smaller, placed on the frontal shield and near zooid margins, varying from oval to subcircular in shape. Each autozooid bearing one or more frontal avicularia. Ovicell longer than wide, with a single median longitudinal suture that is unbranched ( Fig. 7C ), with no lateral sutures, apertural rim straight-edged.

Remarks. This species has two kinds of avicularia, distinguished by size—large asymmetrical avicularia flanking the fenestrulae, and small elongate-oval avicularia on the frontal surface. The ovicell of this species is also distinguished from other species of Triphyllozoon in having an unbranched median longitudinal suture ( Hayward 2000; Tilbrook 2006).

Distribution. Triphyllozoon indivisum was originally described from Sulawesi, Indonesia, and the Solomon Island where it is common at Anuha Reefs, Florida Islands, Mbanika Island and Russell Islands ( Tilbrook 2006).

Figures

FIGURE 2. Preserved samples of Recent bryozoans from the Java Sea, Indonesia. A. Licornia ferox (Busk, 1852). B. Poricel- laria ratoniensis Waters, 1887. C. Smittipora cordiformis Harmer, 1926. D. Celleporaria inaudita Tilbrook, Hayward & Gor- don, 1991. E. Pleurocodonellina jeparaensis n. sp. F. Triphyllozoon indivisum Harmer, 1934. Scale bars: A = 3 mm; B = 6 mm; C = 4 mm; D = 3 mm; E =1 mm; F = 4 mm.

FIGURE 7. Triphyllozoon indivisum Harmer, 1934. A. General view of the colony showing oval fenestrulae and trabeculae. B. Enlargement of large avicularium (arrow), ovicelled zooid, peristomial pore, and frontal avicularia. C. Close-up of small frontal avicularium and ovicell with single longitudinal suture. Scale bars: A = 500 µm; B = 150 µm; C = 100 µm.

Tables

TABLE 6. Measurements (µm) of Triphyllozoon indivisum (KJBR 47). Min. Minimum; Max. Maximum; SE. Standard error; N. Sample size.

	Min	Max	Mean	SE	N
Zooid length	346	403	370	17	15
Zooid width	178	248	219	20	15
Small avicularium length	41	71	57	9	15
Small avicularium width	30	50	41	5	15
Large avicularium length	131	232	198	28	15
Large avicularium width	68	112	93	14	15
Ovicell length	149	238	191	32	15
Ovicell width	30	47	41	5	15