Sicyonia parajaponica Crosnier, 2003

Yang, Chien-Hui, Kumar, Appukuttannair Biju & Chan, Tin-Yam, 2024, On the differences between the two widely distributed and closely related rock shrimps Sicyonia japonica Balss, 1914 and S. parajaponica Crosnier, 2003 (Dendrobranchiata, Penaeoidea, Sicyoniidae), with a new record of S. japonica from Taiwan, Zootaxa 5476 (1), pp. 505-513 : 508-510

Sicyonia parajaponica Crosnier, 2003

( Figs. 2E–F , 3C–D , 4C–D )

? Sicyonia cristata (?).— Pearson 1905: 75 [not Olivier, 1811]. Sicyonia japonica .— Yu & Chan 1986: 56, 3 unnumbered figs.— Liu & Zhong 1988: 249, fig. 150 [not Balss, 1914]. Sicyonia parajaponica Crosnier, 2003: 226 , figs 10– 12, 106E, F [type locality: the Philippines].— De Grave & Fransen 2011:

231.— Thirumilu 2011: 13, fig. 2.— Rajool Shanis et al. 2013: 131, figs 1–3.— Vaitheeswaran 2017: 84, fig. 1.— Chakraborty et al. 2021: 126, fig 1.

Material examined. Taiwan: Northern Three Islets , Keelung, commercial trawlers, Nov 2021, 12 males (cl 16.1–20.5 mm), 5 females (cl 22.4–26.2 mm), NTOU M02592 . Dasi fishing port, Yilan County, 9 Sep 1984, 1 female (cl 14.8 mm), NTOU M02584 ; 29 Sep 1984, 3 males (cl 15.7–20.3 mm), 1 female (cl 18.1 mm), NTOU M02585 ; 7 Jul 1988, 1 male (cl 19.3 mm), NTOU M02586 ; 17 Aug 2011, 2 males (cl 15.8–17.8 mm), 3 females (cl 23.1–25.4 mm), NTOU M02587 . Nanfang-ao fishing port, Yilan County, 1 Sep 1995, 1 male (cl 11.6 mm), NTOU M02588 ; 14 May 1998, 3 males (cl 15.1–16.8 mm), 4 females (cl 8.8–21.1 mm), NTOU M02589 . Pingtung County, Donggang fishing port, 5 Aug 1996, 1 male (cl 14.5 mm), NTOU M02590 ; 7 Nov 1998, 1 female (cl 22.4 mm), NTOU M02591 . Philippines: PANGLAO 2004, stn T2 , 9°32.4’N 123°47.8’E, 152 m, 31 May 2004, 1 male (cl 5.6 mm), NTOU M02593 ; stn T25 , 9°41.1’N 123°49.3’E, 160–210 m, 24 Jun 2004, 1 female (cl 6.5 mm), NTOU M02594 . PANGLAO 2005, stn CP2408, 9°43.5’N 123°47.1’E, 137–153 m, 1 Jun 2005, 1 male (cl 10.3 mm), NTOU M02595 AURORA 2007, stn CP2653, 16°06.5’N 121°59.7’E, 83 m, 20 May 2007, 1 female (cl 7.8 mm), NTOU M02596 ; stn CP2654, 16°04.7’N 121°57.5’E, 98–107 m, 20 May 2007, 1 male (cl 18.5 mm), 2 females (cl 20.9–21.1 mm), NTOU M02597 ; stn CP2747, 15°55’N 121°42’E, 120–124 m, 2 Jun 2007, 2 males (cl 11.0– 13.1 mm), NTOU M02598 . India: Nagapaltinum, Pazhayer fishing harbor, commercial trawlers, Tamil Nadu, 17 Sep 2011, 1 male (cl 14.80 mm), NTOU M02547 ; Jeppiaar fishing harbor, Muttom , 18 Mar 2017, 1 male (cl 21.55 mm), 1 female (cl 22.0 mm), NTOU M02548 ; 28 Feb 2019, 3 males (cl 16.6–19.8 mm), 5 females (cl 15.4–23.8 mm), NTOU M02549 ; 4 Mar 2019, 1 male (cl 18.2 mm), NTOU M02550 .

Diagnosis. Body robust and shell hard. Rostrum short, not exceeding antennular peduncle, tip bifurcated, dorsal margin with 8–10 teeth including 5or 6 postrostral teeth forming a distinct crest, ventral margin with 1 small subdistal tooth. Hepatic tooth well-developed. Infraorbital lobe rounded. Middorsal carina on first pleomere tergite protruded into a strong tooth and directed upward. Anterior end of middorsal carina on second pleomere tergite spine-like. First to third pleomere pleura only sharply pointed ventrally and without other spine. Fourth and fifth pleomere pleura armed with 2–4 spines on posteroventral margin. Male petasma with distal external process of ventrolateral lobe strongly protruded laterally as a blunt triangle; dorsolateral lobe lacking lateral process, external process horn-like while distal internal process lobular, distal internal and external processes similar long. Female thelycum anteriorly protruded into a slender spine, posterior part sunken and greatly expanded laterally.

Fresh coloration. Body generally light brown, dorsal part scattered with black-brown patches and dots of various sizes, ventral part somewhat pinkish ( Fig. 2E ). Posterodorsal carapace bearing a huge circular reddish brown spot, while anterior articulated surface of first pleomere tergite without distinct marking ( Fig. 2F ). Antennular and antennal flagella alternated with narrow white and reddish brown bands. Tail-fan mostly whitish.

Distribution. Western Pacific to Indian Ocean and known with certainty from Taiwan, southern China, the Philippines, Andaman sea, India, northeastern Australia and Gulf of Aden ( Fig. 1 ), at depths of 10–310 m ( Crosnier 2003; Vaitheeswaran 2017; Chakraborty et al. 2021).

Remarks. The present material from Taiwan, the Philippines and India are nearly identical in morphology and coloration ( Fig. 2E, F ; Yu & Chan 1986: 3 unnumbered figs; Crosnier 2003: 106 E, F; Thirumilu 2011: fig. 2; Vaitheeswaran 2017: fig.1; Chakraborty et al. 2021: fig 1). The genetic divergences amongst the specimens from Taiwan (NTOU M02586 COI: OR116129, 16S: OR116183; NTOU M02592 male 16S: OR116184), southern China (MF379619), the Philippines (NTOU M02595 16S: OR116185; NTOU M02598 COI: OR116130, only 618 bp, 16S: OR116186) and India (NTOU M02548 COI: OR116131, 16S: OR116187; MT227281, MN816389, MN816390) are also very low (0% in COI and 0–0.5% in 16S rRNA). As S. parajaponica is now revealed to be rather common in southern India ( Thirumilu 2011; Radhakrishnan et al. 2012; Rajool Shanis et al. 2013; Vaitheeswaran 2017; Chakraborty 2017; Chakraborty et al. 2021), it is highly likely that the material of “ Sicyonia cristata (?)” reported by Pearson (1905) from Sri Lanka represents S. parajaponica as their pleonal pleura are described as all lacking spine.

Figures

FIGURE 1. Global geographic distributions of Sicyonia japonica Balss, 1914 (★) and S. parajaponica Crosnier, 2003 (☆). Symbols within square are records after the revision of Crosnier (2003).

FIGURE 2. A–B, Sicyonia japonica Balss, 1914, Taiwan, male 19.4 mm cl (NTOU M02546); C–D, S. japonica, Madagacar, male 16.6 mm cl (MNHN-IU-2010-4944); E–F, S. parajaponica Crosnier, 2003, India, male 18.2 mm cl (NTOU M02550). A, C & E, left lateral view; B, D & F, dorsal view.

FIGURE 3. Three-dimensional images by micro-computed tomography. A–B, Sicyonia japonica Balss, 1914, Taiwan, male 19.4 mm cl (NTOU M02546); C–D, S. parajaponica Crosnier, 2003, Taiwan, male 16.8 mm cl (NTOU M02589).A & C, entire body, right lateral view; B & D, middorsal carina of first and second pleomere somites, right lateral view.

FIGURE 4. Petasma. A–B, Sicyonia japonica Balss, 1914, Japan, male 19.2 mm cl (NTOU M02582); C–D, S. parajaponica Crosnier, 2003, Taiwan, male 20.1 mm cl (NTOU M02592). A & C, dorsal view; B & D, ventral view.