Perinereis mictodonta ( Marenzeller, 1879 )

Hsueh, Pan-Wen, 2024, Positive association between PTN polymorphisms and schizophrenia in Northeast Chinese Han population., Zoological Studies 63 (39), pp. 141-149 : 30-32

Perinereis mictodonta ( Marenzeller, 1879) ( Fig. 15 , Table 3)

Nereis mictodonta Marenzeller 1879: 118–119 , pl. 2, fig. 2; Izuka, 1912: 148–151, pl. 16, figs. 1–6.

Perinereis mictodonta Wilson and Glasby 1993: 264 ; Glasby and Hsieh 2006: 558–561, fig. 5 (for complete synonym).

Material examined: 2 specimens, NMNS 1955- 22, Kaomei (24°18.50'N, 120°32.42'E), habitat type: ISSB, 10 November 1992; 3 specimens, NMNS 8748- 67, Da’an (24°22.29'N, 120°34.70'E), habitat type: ISSB, 30 January, 1999; 1 specimen, NMNS 8748- 68, Kaomei (24°18.50'N, 120°32.42'E), habitat type: ISSB, 24 August, 1999; 2 specimens, NMNS 3328- 112, Hanbao (24°00.75'N, 120°21.11'E), habitat type: ISSB, 1 February 2000; 1 specimen, NMNS 8748- 69, Wushibi (23°13.70'N, 121°25.08'E), habitat type: IRHB, 16 October 2004; 1 specimen, NMNS 8748- 70, Bazang (23°19.51'N, 120°07.78'E), habitat type: ISSB, 7 January, 2007; 7 specimens, NMNS 8748- 71–78, Fubao (24°02.83'N, 120°22.75'E), habitat type: ISSB, 29 January, 2007; 1 specimen, NMNS 8748-79, Wanggong (23°58.36'N, 120°19.43'E), habitat type: ISSB, 29 January, 2007; 13 specimens, NMNS 8748- 80–83, Fubao, 2 March 2007; 4 specimens, NMNS 8748-84–87, Fuxin (24°03.40'N, 120°24.50'E), habitat type: ISSB, 18 March, 2007; 4 specimens, NMNS 8748- 88–91, Dadu (24°12.77'N, 120°28.06'E), habitat type: ISSB, 20 March 2015; 4 specimens, NMNS 8748-92, Hemei (25°04.91'N, 121°54.93'E), habitat type: ISSB, 17 October 2016.

Description: Based on eight complete specimens ( NMNS 8748-69, NMNS 8748-71–73, NMNS 8748- 79, NMNS 8748-83(1), NMNS 8748-90–91; all atoke) and 14 incomplete specimens ( NMNS 1559-22, NMNS 8748-67(1) –68, NMNS 3328-112, NMNS 8748-70, NMNS 8748-75–78, NMNS 8748-81–82, NMNS 8748- 84–85; all atoke): Body length 41.0–103.0 (n = 8) mm with 82–151 (n = 8) chaetigers, chaetiger 10 width 1.1– 4.0 (n = 22) mm, excluding parapodia; beige in alcohol ( Fig. 15A, B ). Prostomium wider than long, lateral antennae antero-lateral, shorter than palps, palpophores globose, palpostyles spheroid. Four pairs of tentacular cirri, longest one reaching chaetiger 3–13 (n = 20). Two pairs of eyes, in trapezoidal arrangement. Tentacular belt about 1.1–1.4x (n = 21) longer than chaetiger 1. Pharynx with dark brown jaws, each with 3–6 (n = 22) teeth; paragnath pattern: I = 1–6 (mostly 2–5, in cluster or longitudinal line, one case of 1 and two cases of 6, n = 22, same sample size on following areas); II = 14–26 (left), 12–25 (right), in 2–4 oblique rows; III = 15–32 (center region with 11–24 cones, in 3–4 transverse rows; mostly 2 lateral regions, each with 1–6 cones, three case of 3 lateral regions, outer region with 1–2 cones); IV = 23–42 (left), 23–42 (right), in 3–7 oblique rows, without bars; V = 1–4 (mostly 3, in triangle or transverse row, one case of 1 cone, two cases of 2 cones, four cases of 4 cones); VI = 3–9 uneven-length bars, innermost and outermost longest (left), 3–8 uneven-length bars, innermost and outermost longest (right); VII –VIII = 20– 39, in 2 rows, posterior row zigzagged. Ridge pattern of areas VI – V – VI, χ-shaped ( Fig. 15A, B , Table 3).

Dorsal cirri digitiform, medially attached dorsal ligule throughout, about 0.8x as long as dorsal ligule on anterior to mid-body chaetigers, about 0.5x as long as dorsal ligule on posterior chaetigers ( Fig. 15C–E , Table 3).

Dorsal ligule subconical throughout, about 2.0x longer than median ligule on anterior to mid-body chaetigers, about 1.3x longer than median ligule on posterior chaetigers; center lobe of dorsal ligule with one irregular-shaped glandular mass on posterior chaetigers ( Fig. 15C–E ). Notopodial prechaetal lobe absent ( Table 3).

Median ligule subconical throughout, greatly longer than neuroacicular ligule throughout ( Fig. 15C– E ).

Neuroacicular ligule with prominent inferior lobe on anterior to mid-body chaetigers, about as long as ventral ligule, inferior and superior lobes subequal in length on posterior chaetigers, about as long as ventral ligule. Neuropodial postchaetal lobe absent. Ventral cirri digitiform, mid-ventrally attached to ventral edge of parapodia on anterior to mid-body chaetigers, about 0.9x as long as ventral ligule, distally attached to ventral ligule on posterior chaetigers, about 0.6x as long as ventral ligule ( Fig. 15C–E ).

Notochaetae present from chaetiger 3 to posterior chaetigers, homogomph spinigers present throughout. Supra-acicular fascicle of neuropodia: homogomph spinigers and medium-sized blade heterogomph falcigers with serrations present throughout. Subacicular fascicle of neuropodia: medium-sized blade heterogomph falcigers with serrations and heterogomph spinigers present throughout ( Fig. 15F , Table 3).

Pygidium with anus crenulated; anal cirri cirriform, as long as last 4–8 (n = 5) chaetigers.

Remarks: The morphology of examined specimens in the present study agrees with description of P. mictodonta ( Marenzeller, 1879) in Glasby and Hsieh (2006: 599–561, fig. 5A–F) ( Fig. 15A–F , Table 3). All examined specimens of P. mictodonta in the present study were mostly collected from soft bottom on river mouths and coastal flats of central-west Taiwan, which largely agree with distribution of this species in Taiwan reported by Glasby and Hsieh (2006: 555, fig. 1). Glasby and Hsieh (2006: 555, fig. 1) commented that no polychaete in the Perinereis nuntia group were found from river mouths on east coasts of Taiwan. However, the present distribution record of P. mictodonta in Taiwan showed one exception. One specimen of P. mictodonta was collected from rocky tide pool in coasts of Wushibi, eastern Taiwan. Presumably, windy seasons on east coasts of Taiwan provide suitable temporal living environment in rocky tide pool (i.e., sediment and algae brought in by strong wave actions) for larvae of P. mictodonta to settle and grow in that environment. This favorable living environment of biota vanished during summer with weak wave actions and high evaporation.

Figures

Fig. 15. Perinereis mictodonta (Marenzeller, 1879); A, B (NMNS 8748-79); C–F (NMNS 8748-76): A, anterior body region, dorsal view; B, closeup of areas V and VI of the pharynx; C, right parapodium, anterior view, chaetiger 10; D, right parapodium, anterior view, chaetiger 30; E, right parapodium, anterior view, chaetiger 55; F, neuropodial subacicular fascicle chaetae, chaetiger 10. Abbreviations: HeF = heterogomph falciger; HeS = heterogomph spiniger. Scale bars:A, B = 0.5 mm; C–E = 0.2 mm; F = 0.02 mm.