Parapenaeopsis cornuta ( Kishinouye, 1900 )

Parapenaeopsis cornuta ( Kishinouye, 1900) View in CoL

( Figs. 2 View FIGURE 2 , 6b View FIGURE 6 )

Penaeus cornutus Kishinouye, 1900: 23 View in CoL , unnumbered text fig., p1. 7-figs. 9, 9A (type locality: Japan).

[not] Parapenaeopsis cornutus — Parisi 1919: 64, pl. 5-figs. 1, 12; Chang 1965: 15., 3 unnumbered figs. (= P. amicus V.C. Nguyên, 1971 View in CoL )

? [not] Parapenaeopsis cornutus — Maki & Tsuchiya 1923: 43, pl. 4-1. (= P. amicus V.C. Nguyên, 1971 )

? Parapenaeopsis cornutus — Kubo 1949: 374 (in part—Taiwanese material).

Parapenaeopsis cornuta View in CoL — Lee & Yu 1977: 87 (in part), figs. 59A–C, E; Liu & Wang 1987: 524, fig. 2; Liu & Zhong 1988: 208, fig. 129; Perez Farfante & Kensley 1997:120; Lee et al. 1999: 445.

[not] Parapenaeopsis cornuta View in CoL — Lee & Yu 1977: 87 (in part), figs. 58(?), 59D; Ma et al 2009: table 1. (= P. amicus V.C. Nguyên, 1971 View in CoL )

? Parapenaeopsis cornuta View in CoL — Yu & Chan 1986: 121 (in part), unnumbered photo.

? Parapenaeopsis cornuta View in CoL — Yu & Chan 1986: 121 (in part), fig. 19B. (= P. amicus V.C. Nguyên, 1971 View in CoL )

Kishinouyepenaeopsis cornuta View in CoL — Sakai & Shinomiya 2011: 499, figs. 3A, B, 4F; De Grave & Fransen 2011: 216.

Material examined. Yilan County, Dasi fishing port, 10 Mar 1985, 2 males cl 14.5–18.4 mm ( NTOU M02355 View Materials ) ; 5 Aug 1982, 1 male cl 22.9 mm, 1 female cl 28.9 mm ( NTOU M02356 View Materials ) . Keelung City, 12 Oct 1990, 1 male cl 13.6 mm ( NTOU M02357 View Materials ) . Changhua County, Wenzi fishing port, 5 Aug 2021, 3 males cl 16.6–17.4 mm, 39 females cl 17.2–22.0 mm ( NTOU M02358 View Materials ) . Chiayi County, Budai fishing port, 26 May 1974, 2 females cl 18.0– 18.7 mm ( NTOU M02359 View Materials ) ; 20 Jan 1995, 1 female cl 18.2 mm ( NTOU M02360 View Materials ) ; 2 Jul 2002, 1 female cl 13.6 mm ( NTOU M02485 View Materials ) . Kaohsiung City, Singda fishing port, 24 Jul 1984, 2 females cl 16.1–17.0 mm ( NTOU M02361 View Materials ) .— Kaohsiung port, station 4, 1 Mar 1994, 2 males both cl 18.1 mm ( NTOU M02362 View Materials ) .— Cijin , 25 Mar 1996, 4 males cl 18.6–19.5 mm, 7 females cl 19.1–23.1 mm ( NTOU M02363 View Materials ) . Pingtung County, Donggang fishing port, 28 Jul 1985, 2 males cl 15.1–16.8 mm, 2 females cl 19.2–19.3 mm ( NTOU M02364 View Materials ) . No specific data, 2 females cl 21.1–21.2 mm ( NTOU M02419 View Materials ) ; 2 males cl 19.0– 19.2 mm, 2 females cl 23.1–23.4 mm ( NTOU M02486 View Materials ) ; 1 male cl 18.3 mm, 3 females 16.2–22.8 mm ( NTOU M02487 View Materials ) .

Diagnosis. Rostrum horizontal straight, extending to distal segment of antennular peduncle and often reaching tip of antennular peduncle, armed with 6–8 (excluding epigastric tooth) dorsal teeth but with tip devoid of tooth and slightly curved upwards. Longitudinal suture short and only more or less reaching level of epigastric tooth. Pereiopods I and II with basial spines and epipods. Pereiopod III with basial spine always absent in female but occasionally present in males. Abdominal somites I and II without dorsal carina. Telson without movable lateral spinules. Males with endopod of pleopod II strongly modified into sock-like shape; petasma lacking distomedian projection but with distolateral projections strongly elongated and horn-like, tip of horn distinctly protruded at outer side. Female thelycum with anterior plate semi-circular to semi-quadrate, anterior margin with median part occasionally slightly protruded, surface somewhat sunken and rarely with median longitudinal furrow; posterior plate with a median boss, lateral parts as large semicircular process; tuft of setae behind posterior plate long and thick.

Coloration. Very similar to P. amicus except tuft of long setae behind thelycum bluish.

Distribution. Widely disturbed in the Indo-West Pacific from India to Japan and Australia, intertidal to about 40 m deep ( Chan 1998).

Remarks. Parapenaeopsis cornuta has long been reported from Taiwan more than a century ago ( Parisi 1919). However, this species has a lot of taxonomic confusions in literature. There are three other named species closely related to P. cornuta and Sakai & Shinomiya (2011) erected a separate genus Kishinouyepenaeopsis for these four species (see also De Grave & Fransen 2011). These four “ Kishinouyepenaeopsis ” are P. cornuta , P. maxillipedo , P. amicu s and P. incisa . Both P. cornuta (type locality: Japan) and P. maxillipedo (type locality: India) have wide Indo-West Pacific distribution and with overlaps from India to the Philippines and Australia (see Perez Farfante & Kensley 1997; Chan 1998). These two species appear differ only in females with the basial spine at the pereiopod III present in P. maxillipedo but absent in P. cornuta (see De Man 1911; Kubo 1949; Dall 1957; Hall 1961; Rack & Dall 1965; Racek & Yaldwyn 1971; Motoh & Buri 1984; Liu & Wang 1987; Liu & Zhong 1988; Chan 1998; Chanda 2016b). In the original description, Alcock (1906) already suspected that P. maxillipedo may belong to the same species with P. cornuta and some later workers (e.g., De Man 1911; Rack & Dall 1965; Racek & Yaldwyn 1971, Dall & Rothlisberg 1990) had synonymized them or treated them as subspecies. For P. amicu s and P. incisa , they were recently separated from P. cornuta (see “Remarks” under P. amicus ) but also considered as junior synonyms of the latter by some workers (e.g., Dall & Rothlisberg 1990). Nevertheless, these two species differ from P. cornuta , as well as P. maxillipedo , in the posterior plate of the thelycum lacking a median boss (see Liu & Wang 1987; Liu & Zhong 1988; Hurzaid et al. 2020). Molecular analyses also support that P. amicu s and P. incisa are distinct from P. cornuta ( Li et al. 2014; Hurzaid et al. 2020), even though material currently identified as P. cornuta may composed of as many as five species ( Hurzaid et al. 2020). Even though the exact characteristics of P. maxillipedo are still uncertain, the present Taiwanese material is identified with P. cornuta by the pereiopod III always lacking a basial spine in females. Only in one (NTOU M02356) of the males examined has the pereiopod III bearing a basial spine.

Liu & Wang (1987) and Liu & Zhong (1988) considered that the Taiwanese material of P. cornuta reported by Lee & Yu (1977) was a mixture of P. cornuta ( Lee & Yu 1977: fig. 59C male pleopod II endopod), P. incisa ( Lee & Yu 1977: fig. 59A, B petasma) and P. amicu s ( Lee & Yu 1977: fig. 59D thelycum). Of the three lots of material examined in Lee & Yu (1977), only six specimens (NTOU M02359, M02418) matching the locality and date of the P 211 lot (Budai fishing port, Chiayi County, 26 May 1974) are found. These six specimens composed of three males and three females, with males all belong to P. cornuta and females belong to either P. cornuta or P. amicus . The P 211 lot of Lee & Yu (1977) consisted of only one female while the female from NTOU M02418, belonging to P. amicus , is much larger and has the thelycum similar to the size and shape of the thelycum illustrated in Lee & Yu (1977: 59 D; also see “Remarks” under P. amicus ). Although the tip of the distolateral horn of the petasma illustrated in Lee & Yu (1977: fig. 59A, B) is similar to those of P. incisa ( Liu & Wang, 1987: fig b, c; Liu & Zhong, 1988: fig. 130-2, 3), the difference in this small structure between P. cornuta and P. incisa is subtle and the illustrations of Lee & Yu (1977: fig. 59A, B) might just be not detailed enough. Parapenaeopsis incisa mainly differs from P. cornuta in the thelycum with the posterior plate lacking a median boss (see Hurzaid et al. 2020) while all other differences proposed ( Liu & Wang 1987; Liu & Zhong 1988) are rather subtle. Until there is a confirm record of P. incisa from Taiwan, the report of “ P. cornuta ” by Lee & Yu (1977) is considered to consist of P. corunta and P. amicus for the time being.

For other previous records of P. cornuta in Taiwan, those by Parisi (1919), Maki & Tsuchiya (1923), Chang (1965) and Ma et al. (2009) are or likely are P. amicus as discussed under the “Remarks” of the latter species. On the other hand, the photograph given in Yu & Chan (1986) likely represents the true P. cornuta . The material of P. cornuta examined by Kubo (1949) was from Japan and Taiwan. Although the pleopod II endopod of males and thelycum illustrated by Kubo (1949: figs. 47N, 63B) generally match the characteristics of P. cornuta , his illustrations and descriptions were all based on Japanese material and therefore it is not sure if Kubo’s (1949) Taiwan specimens are truly P. cornuta .