Chauliopleona hastata ( Hansen, 1913 )

Bird, Graham John, 2015, Tanaidacea (Crustacea: Peracarida) of the northeast Atlantic: Chauliopleona Dojiri and Sieg, 1997 and Saurotipleona n. gen. from the ‘ Atlantic Margin’, Journal of Natural History 49 (25), pp. 1507-1547 : 1530-1535

Chauliopleona hastata ( Hansen, 1913)

( Figures 1H–M , 11–13 , 17A , 18 )

Leptognathia hastata Hansen, 1913: 79–80 , pl. VII figs. 7a–g

Leptognathia hastata: Nierstrasz 1913: 30 ; Stephensen 1932: 348; else, see Sieg 1983

Chauliopleona hastata: Guerrero-Kommritz 2005: 1191–1195 , figs. 7–8; else, see Anderson 2013

Diagnosis

Cephalothorax 1.2 times ltb. Pereonites all shorter than broad; with parallel or weakly convex lateral margins. Pleon shorter than cephalothorax, pleonites 1–4 sternite without prominent sternal process. Antennule article-1 as long as rest of antennule. Maxilliped basis with long seta. Cheliped merus without inferior protuberance; carpus stout, 1.6 times ltb, inferior shield deep (aspect ratio ≈ 0.36–0.4), rounded, distal margin not angular; fixed finger with four teeth; dactylus superior margin smooth. Pereopods 1–3 basis margins smooth; carpus and propodus inferior spinules weak. Pereopod-1 dactylus and unguis short, about 2/3 length of propodus. Pereopods 2–3 carpus without distomedial seta. Pereopods 4–6 ischium with two short setae. Uropod endopod <three times length of peduncle; exopod half as long as endopod segment-1.

Material examined

AFEN stns. One non-ov. ♀ , 53715#1; one?prep. ♂, 53716#1; one?prep. ♂, 53828#1; one non-ov. ♀, two non-ov. ♀♀, 53832#1; one non-ov. ♀, 53835#1; one?prep. ♂, 53839#1; two non-ov. ♀♀, 54516; one non-ov. ♀, 54523#1/2; one non-ov. ♀, 54524#2; one non-ov. ♀, 54525#1/2; one prep. ♂, 54526#3; one non-ov. ♀ /early prep. ♂, 55278#1; one non-ov. ♀, 55282#1; one non-ov. ♀, 55283#1; one prep. ♂, 55283#2; one non-ov. ♀, 55284#1; one non-ov. ♀, 55296#1; one non-ov. ♀, 55300#1; one non-ov. ♀, 55300#2; one ind., 55304#2; one non-ov. ♀, 55308#1; one non-ov. ♀, one ov. ♀, three post.ov. ♀♀, 55316#2/3; one non-ov. ♀, 55317#1/2; one non-ov. ♀, 55398#1/2; one non-ov. ♀, 55445#1/2; one non-ov ♀, one post-ov. ♀, one prep. ♂, 55447#10; two non-ov. ♀♀, 55447#13; one non-ov. ♀, 57030#1; one nonov. ♀, 57031#1/2; one?prep. ♂, 57032#1; one non-ov. ♀, 57036#1; one post-ov. ♀, 57068#1; one non-ov. ♀, 57075#1.

BIOFAR stn. Two early prep. ♂♂ , 9009.

BIOICE stns. One ov. ♀ , 2102; eight non-ov. ♀♀ (one dissected on microslide), two prep. ♂♂, 2027; one non-ov. ♀, 2647; three non-ov. ♀♀, 2648; one non-ov. ♀, 2773; two non-ov. ♀♀, 2776; one prep. ♂, 3143; one prep. ♂, 3187; three non-ov. ♀♀, 3219; one non-ov. ♀, 3222; one non-ov. ♀, 3225.

Co-types. Two non-ov. ♀♀, Ingolf Stn 102; one non-ov. ♀ Stn 125.

Size

Non-ovigerous female. Body length 1.79–3.85 mm, cf. 2.5–2.8 mm Hansen (1913). Ovigerous/post ovigerous female: body length 2.55–3.27 mm. Preparatory male: body length 2.20–3.15 mm.

Distribution records from the AFEN, BIOICE and BIOFAR area

33 records from AFEN surveys: 31 from the Faroe-Shetland Channel , 1026–1741 m, one from the Norwegian Basin 2064 m, one from the West Shetland Slope , 400 m. One record from BIOFAR: Norwegian Basin , 1261 m. Eleven records from BIOICE: two from Denmark Strait , 1012–1146 m, one from the Irminger Basin , 1326 m, five from the Iceland Plateau , 1300–1646 m, one from the Jan Mayen Ridge , 1529 m, and two from the Norwegian Basin, 1639–1994 m; almost all bottom temperatures are negative, ranging from −0.9°C to −0.6°C, but with the exception of Irminger Basin Stn 3187, 3.99°C. A variety of sediments types are recorded including ‘very fine sand’, ‘sandy mud’, ‘silt’ and ‘gravelly sandy silt’ .

Also in the area: Ingolf Stn 102, 1412 m, and Stn 125, 1372 m ( Hansen 1913); overall depth range 400?– 1994 m.

Distribution elsewhere

Fifteen records from the deep Norwegian Basin (NORBI survey, Bird unpub.) 2470– 3709 m.

Remarks

This species is recognised by its stout cheliped carpus (1.6 times ltb, Figure 12J ) with its deep and rounded inferior shield, while its pereopods 1–3 ( Figure 13A–C ) are more robust compared to those of C. amdrupii and C. armata . The pleonal sternites are also lower than in C. armata and C. amdrupii . The cheliped shown by Guerrero- Kommritz (2005, fig. 7b, f) based on non-type material from the Greenland Sea at 188–191 m is far more massive and angular than those illustrated here from the cotype and new topotypical material, and is more similar to that of the new genus described below. Similarly, his drawing of the pereopod-5 ( Guerrero-Kommritz 2005, fig. 8l) suggests that it may not be C. hastata . Another Atlantic species, C. amftae from the abyssal Angola Basin, also has a robust cheliped but this taxon differs from C. hastata at least by having a proportionately longer cephalothorax (> pereonites 1–2), a small protuberance/apophysis on the cheliped merus and fewer pleopodal setae.

Chauliopleona hastata is a cold-water species with an overall recorded depth range of 400–3709 m, i.e. it is primarily characteristic of the Arctic area of the Norwegian Sea , but there is a single, possibly spurious, record from the West Shetland Slope at 400 m (SEA-4 Stn 57075#1). The record of a preparatory male from the Irminger Basin ( BIOICE Stn 3187) also looks anomalous but the specimen appears to have characters consistent with C. hastata , such as its robust cheliped ( Figure 17A ) .

Figures

Figure 1. Chauliopleona. Sketch drawings: (A) measurement of cheliped carpal shield aspect ratio l/b; C. armata, non-ovigerous female, co-type, Ingolf Stn 22; (B) habitus; (C) pleonite-5 spur; (D) cheliped, distal; (E) cheliped, fixed finger; (F) pereopod-1, distal; (G) uropod. C. hastata, non-ovigerous female co-type, Ingolf Stn 125: (H) habitus; (J) pleonite-5 spur, pleotelson, and uropod; (K) cheliped, distal; (L) pereopod-1, distal; C. hastata one of two cotypes, Ingolf Stn 102: (M) pleonite-5 spur. Not to scale.

Figure 11. Chauliopleona hastata. Non-ovigerous female, BIOICE Stn 2027: (A) habitus; (B) pleonal sternites, lateral; (C) pleonite-5 spur variant; (D) antennule; (E) antenna; (F) uropod. Preparatory male, BIOICE Stn 2027: (G) habitus; (H) antennule. Scale bars: (i) 1 mm for A, G; (ii) 0.5 mm for B–C, 0.25 mm for D–F, H.

Figure 12. Chauliopleona hastata. Non-ovigerous female, BIOICE Stn 2027: (A) labrum; (B–C) left and right mandibles, respectively; (D) maxillule; (E) maxilla; (F) maxilliped (one palp omitted); (G) maxilliped palp article-2 mesial setation; (H) epignath; (J) cheliped; (K) cheliped propodus mesial comb. Scale bars: (i) 0.25 mm for A–H; (ii) 0.25 mm for J–K.

Figure 13. Chauliopleona hastata. Non-ovigerous female, BIOICE Stn 2027: (A–F) pereopods 1–6, respectively; (G) pleopod (setae very finely plumose, omitted for clarity). Scale bar 0.25 mm.

Figure 17. Sketch drawings of Chauliopleona and Saurotipleona. (A) C. hastata?, BIOICE Stn 3187; (B) C. armata sensu lato, Thalassa-73 Stn Z.426; (C–E) S. julii, INCAL ØS.04, cheliped, pleon and pleonite-5 spur, respectively. Not to scale.

Figure 18. Distribution of Chauliopleona species in the Atlantic Margin area. Filled triangles C. amdrupii, filled squares C. armata, and filled circles C. hastata; crosses indicate Ingolf records of C. hastata.