Prionocrangon curvicaulis Yaldwyn, 1960

Kim, Jung Nyun & Chan, Tin-Yam, 2005, A revision of the genus Prionocrangon (Crustacea: Decapoda: Caridea: Crangonidae), Journal of Natural History 39 (19), pp. 1597-1625 : 1613-1615

Prionocrangon curvicaulis Yaldwyn, 1960

( Figure 7 )

Prionocrangon n. sp.: Richardson and Yaldwyn 1958, p 39, Figure 41.

Prionocrangon curvicaulis Yaldwyn 1960, p 46 , Figure 10 [type locality: Chatham Rise , New Zealand].

Not Prionocrangon curvicaulis: Chace 1984, p 56 (key), 57, Figure 24 [5 Prionocrangon ommatosteres Wood-Mason and Alcock, 1891 ].

Material examined

New Zealand. Catham Rise , CIE (Catham Islands 1954 Expedition), stn 6, 43 ° 409S, 179 ° 289E, 402 m, 24 January 1954, beam trawl and large dredge, fine grey sandy mud, 1 „ (CL 6.5 mm), paratype, MNZ CR 7378 .

Type material

Holotype: New Zealand, Catham Rise, CIE, stn 6, 43 ° 409S, 179 ° 289E, 402 m, 24 January 1954, beam trawl and large dredge on bottom fine grey sandy mud, 1 ovig. ♀ (CL 9 mm), Canterbury Museum . Paratypes: New Zealand, Catham Rise, CIE, same data as holotype, 1 „ (CL 6.5 mm, stated in original description as 6 mm), MNZ CR 7378 , 1♀ (CL 7.5 mm), Canterbury Museum; stn 7, 43 ° 429S, 179 ° 559E, 509 m, 24 January 1954, beam trawl, fine grey sandy mud, 1♀ (CL 7 mm), 2 ovig. ♀♀ (stated as CL 8 mm), Canterbury Museum; stn 41, 44 ° 35.59S, 176 ° 049E, 600 m, 3 February 1954, otter trawl, fine green muddy sand, 1♀ (CL 8 mm), Canterbury Museum ; stn 52, 44 ° 049S, 178 ° 049E, 473 m, 10 February 1954, beam trawl and large dredge, fine green sandy mud, 1♀ (CL 9 mm), 1 ovig. ♀ (CL 8 mm), Canterbury Museum. Only the male paratype examined .

Description

Rostrum extending to tip of branchiostegal spine, 0.20 times as long as carapace ( Figure 7A ). Mid-dorsal carina of carapace armed with 7–11 spines ( Figure 7A ). Fourth and fifth abdominal somites without median carina; sixth somite 0.58 times as long as carapace, posterior margin of posterolateral process rounded, with minute tooth and deep excavation ventrally ( Figure 7E ). Telson slightly shorter than sixth abdominal somite ( Figure 7D ), 0.53 times as long as carapace, posterior half strongly convergent ( Figure 7F ); posterior margin bearing six to seven long spines and with or without minute median denticle ( Figure 7G ). Eyestalks drawn out to bluntly cylindrical extremities and curving ventrally in between antennules ( Figure 7C ). Antennular peduncle with proximal segment relatively short, 0.58 times as long as carapace ( Figure 7B ). Stylocerite with tip elongate and sharp ( Figure 7C ). Scaphocerite overreaching distal margin of second segment of antennular peduncle, 0.69 times as long as carapace ( Figure 7B ). Palm of first pereopod moderately slender, 4.97 times as long as wide ( Figure 7H ). Dactyli of fourth and fifth pereopods relatively long, 0.74 times as long as propodi ( Figure 7J ).

Size

Male CL 6.5 mm, females CL 7–9 mm, ovigerous females CL 8–9 mm ( Yaldwyn 1960).

Distribution

New Zealand (Chatham Rise), at depths of 402–600 m.

Colour in life

Described by Yaldwyn (1960, p 48) as entire animal purely white.

Remarks

Prionocrangon curvicaulis is known only from the type series. Except for the male paratype deposited now at the Museum of New Zealand, the holotype and other paratypes deposited at the Canterbury Museum were not located by the present study. A re-examination of the male paratype found that its telson has the posterior margin bearing seven long spines and lacking a median denticle ( Figure 7G , versus bearing three pairs of long spines and with a minute median denticle as described for the holotype). Other characters present in the paratype male but not mentioned by Yaldwyn (1960) are: (1) posterior margin of posterolateral process of sixth abdominal somite rounded, with a minute denticle and a deep excavation ventrally ( Figure 7E ); (2) first pereopod with carpus having a small distolateral spine ( Figure 7I ) and merus bearing a small subdistal spine on dorsal margin ( Figure 7I ).

Prionocrangon curvicaulis appears to be related to the new species P. formosa in having a cylindrical eyestalk with rounded tip ( Figure 7C ), the rounded posterior margin of the telson ( Figure 7G ), the proportionally shorter proximal antennular segment ( Figure 7A, B ) and the relatively longer dactyli of the fourth and fifth pereopods ( Figure 7J ). However, the rostrum of P. curvicaulis (0.20 times carapace length and extending to tip of branchiostegal spine, Figure 7A ) is distinctly longer than that of P. formosa (0.07 times carapace length and only reaching tip of antennal spine, Figure 8A ). The branchiostegal spine is also much better developed in P. curvicaulis ( Figure 7A ) than in P. formosa ( Figure 8A ). The shape of the posterolateral process of the sixth abdominal somite is also different between these two species ( Figures 7E versus 8E) and the telson is posteriorly more convergent in P. curvicaulis ( Figure 7F ) than in P. formosa ( Figure 8F ).

Figures

Figure 7. Prionocrangon curvicaulis Yaldwyn, 1960, paratype male (CL 7.0 mm) from Chatham Rise, New Zealand, CIE stn 6. (A) Carapace (tip of rostrum broken) with cephalic and thoracic appendages, lateral; (B) carapace (tip of rostrum broken) and anterior cephalic appendages, dorsal; (C) anterior part of carapace (tip of rostrum broken), eyes, basal parts of antennule and antenna, dorsal; (D) posterior part of abdomen and tailfan, lateral; (E) posterolateral process of sixth abdominal somite, lateral; (F) telson, dorsal; (G) posterior part of telson, dorsal; (H) chela of left first pereopod, ventral; (I) carpus and distal part of merus of left first pereopod, lateral; (J) dactylus and propodus of left fourth pereopod, lateral; (K) left first pleopod, ventral; (L) left second pleopod, ventral; (M) appendix masculina, same, ventral.

Figure 8. Prionocrangon formosa sp. nov., holotype female (CL 4.9 mm) from Taiwan, TAIWAN 2001 stn CP 104. (A) Entire animal, lateral; (B) same, dorsal; (C) anterior part of carapace, eyes, basal parts of antennule and antenna, dorsal; (D) sixth abdominal somite and tailfan, dorsal; (E) posterolateral process of sixth abdominal somite, lateral; (F) telson, dorsal; (G) eyes, dorsal; (H) same, lateral; (I) chela and carpus of right pereopod, dorsal; (J) dactylus and propodus of right fourth perepod; (K) right first pleopod, ventral; (L) right second pleopod, ventral.

Figure 10. Prionocrangon paucispina sp. nov. (A–C, E, F, H, I, K–M) Paratype female (CL 9.0 mm) from New Caledonia, BIOCAL stn CP 72; (D) paratype male (CL 7.2 mm) from Taiwan, TAIWAN 2002 stn CP 185; (G) paratype female (CL 8.0 mm) from New Caledonia, BIOGEOCAL stn CP 273; (J) paratype female (CL 5.8 mm) from Taiwan, TAIWAN 2002 stn CP 185; (N) holotype male (CL 7.6 mm) from TAIWAN 2002 stn CP 185. (A) Carapace with cephalic and thoracic appendages, lateral; (B) carapace and anterior cephalic appendages, dorsal; (C, D) anterior part of carapace, eyes, basal parts of antennule and antenna, dorsal; (E) posterior part of abdomen and tailfan, lateral; (F, G) posterolateral process of sixth abdominal somite, lateral; (H) telson, dorsal; (I, J) posterior part of telson, dorsal; (K) chela of right first pereopod, ventral; (L) dactylus and propodus of left fourth pereopod, lateral; (M) left second pleopod, ventral; (N) appendix masculina of left second pleopod, mesial.