Acryptolaria minuta Watson, 2003

Cantero, Álvaro Luis Peña, 2024, Fig. 4 in Positive association between PTN polymorphisms and schizophrenia in Northeast Chinese Han population., Zoological Studies 63 (17), pp. 141-149 : 4

Acryptolaria minuta Watson, 2003 ( Fig. 3A )

Acryptolaria minuta Watson, 2003: 163−164 , fig. 13A–C; Peña Cantero and Vervoort, 2010: 302–304, figs. 18, 30; Peña Cantero, 2020: 288, figs. 1D, 3E−F, 5G.

Material examined: Stn 98, one stem fragment 9 mm long with several hydrothecae, without coppinia ( NIWA 114754).

Description: Stem fragment 9 mm long, with hydrothecae arranged alternately in two planes forming a very open angle. Hydrotheca markedly curved outwards, tubular, free part cylindrical, diameter barely dwindling basally at adnate part. Hydrotheca adnate to internode for about two-thirds of its length. Free adcauline wall strongly convex; adnate part much less so. Abcauline wall concave, but nearly straight at basal part. Hydrothecal aperture circular, directed outwards, often parallel to longitudinal axis of branch; rim even, with up to four renovations.

Measurements (in µm): Hydrothecae: abcauline wall 680−700, free part of adcauline wall 230−350, adnate part of adcauline wall 550−570, adcauline wall 850−860, diameter at aperture 110−130, diameter at base 80. Cnidome (taken with × 40): putative macrobasic mastigophores, range 17.5–20 × 7.5.

Remarks: The material consists of a single stem fragment, 9 mm long; however, the specimen corresponds well to recent descriptions of the species by Peña Cantero and Vervoort (2010) and Peña Cantero (2020). The species is well characterised by the shape and size of the hydrotheca and the size of the larger nematocysts (e.g., 17–19 × 7–8 µm in Peña Cantero and Vervoort 2010).

Ecology and distribution: Acryptolaria minuta has been collected from depths of 300 ( Peña Cantero and Vervoort 2010) to 1422 m ( Watson 2003); present material from 676 to 750 m.

This species has been previously recorded north of Macquarie Island ( Watson 2003), from the Loyalty Islands and Norfolk Ridge areas ( Peña Cantero and Vervoort 2010) and off Antipodes Island, southeast of New Zealand ( Peña Cantero 2020). The material studied here was collected from Seamount 9 Hjort, south of Macquarie Island.

Figures

Fig. 3. Acryptolaria minuta Watson, 2003: A, hydrothecae. Acryptolaria operculata Stepanjants, 1979; B, distal part of hydrotheca. Acryptolaria seamountensis sp. nov.: C−F, hydrothecae and hydrothecal disposition; G, putative macrobasic mastigophore (arrow). Acryptolaria sp.: H, hydrothecae and hydrothecal disposition. Scale bars: A−F, H = 200 μm; G = 10 μm.