Chauliopleona armata ( 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 : 1519-1524

Chauliopleona armata ( Hansen 1913)

( Figures 1B–G , 5–7 , 18 )

Leptognathia armata Hansen, 1913: 80–81 , pl. VIII figs. 1a–f

Leptognathia armata: Nierstrasz 1913: 30 ; Stephensen 1932: 347; Stephensen 1943: 36, 63; Holdich and Bird 1985: 443 table 1; else, see Sieg 1983

Chauliopleona armata: Guerrero-Kommritz 2005: 1188–1191 , figs. 5–6; else, see Anderson 2013

Diagnosis

Cephalothorax 1.3–1.6 times ltb. Pereonites all shorter than broad; with parallel lateral margins. Pleon shorter than cephalothorax, without posteriodorsal protuberance; pleonites 1–4 sternite with subtriangular sternal process. Antennule article-1 (1.2 times) longer than rest of antennule. Maxilliped basis with long seta. Cheliped merus without inferior protuberance; carpus fairly stout, 1.6 times ltb, inferior shield shallow (aspect ratio ≈ 0.3), rounded, distal margin not angular; fixed finger with four teeth; dactylus superior margin smooth. Pereopods 1–3 basis margins smooth; propodus inferior spinules numerous, moderate or robust. Pereopods 2–3 carpus without distomedial seta. 1 Pereopods 4–6 ischium with two short setae. Uropod exopod about half as long as endopod segment-1; endopod> three times longer than peduncle.

Material examined

BIOICE stns. One non-ov. ♀ , 2810; 21 non-ov. ♀♀ (one dissected on microslide), 18 prep. ♂♂, 2856; one non-ov. ♀, one prep. ♂, 2859; six non-ov. ♀♀, one ov. ♀, two prep. ♂♂, 2860; one non-ov. ♀, one prep. ♂, 2863; one prep. ♂, 3067; one prep. ♂, 3071; one non-ov. ♀, 3504; one non-ov. ♀, 3515.

AFEN Stn. One individual, 54591#1; one non-ov. ♀ , 54600#2.

Co-type. Non-ov. ♀, Ingolf Stn 22.

Other material. SMBA stns: one individual (ind.), ES105; four ind., ES218; two ind., SBC61; two ind., one ind., SBC68; SBC166; one ind., SBC216. INCAL stns: one ind., CP01; two ind., CP02; one ind., DS01.

Size

Non-ovigerous female. Body length 2.28–3.64 mm, cf. 3.6 mm as measured by Hansen (1913) or 3.8 mm by Guerrero-Kommritz (2005). Ovigerous female: body length 2.96 mm.

Preparatory male. Body length 2.72–3.44 mm, cf. 3.3 mm Hansen (1913).

Distribution records from the AFEN, BIOICE and BIOFAR area

Eleven from AFEN: two from North Feni Ridge , 1600–2000 m, eight from the northern Rockall Trough , 1859–1871 m, and one from the Hebrides Slope , 1800 m. Ten records from BIOICE: all from the Iceland Basin, 1333–2400 m; with positive bottom temperatures 2.1–3.99°C and a variety of sediment types including ‘silty sand’, ‘shell debris’, ‘silt’ and ‘muddy gravel’ .

Distribution elsewhere

The type locality is the Davis Strait , 2702 m, and southwest of Cape Farewell , 3474 m ( Hansen 1913). I have 51 records from the northeast Atlantic , extending from the Iceland Basin (deeper and further south than the BIOICE area) to the southern Bay of Biscay , including the South Feni Ridge , Rockall Trough , Porcupine Seabight , Celtic and Armorican Slopes , and Biscay Abyssal Plain , 1180–4823 m ( SMBA, IOS, COB, Chain-106). Some of these were reported by Holdich and Bird (1985). These data are available from the author on request .

Remarks

A significant problem in assessing any new records of C. armata is that the original type material consists of only two specimens ( Figure 1B–G ) and this shows some differences from the specimens illustrated here that have a slightly shorter cephalothorax and somewhat weaker propodal spinules on pereopods 1–3 ( Figure 7A–C ). If these new records are genuine, Chauliopleona armata appears to be a eurybathic species, inhabiting both bathyal (200–2000 m) and abyssal zones (2000–6000 m). However, it is almost certain that the records of C. armata outside of the Atlantic Margin study area (see above) refer to more than one species, and the material needs re-examination.

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 5. Chauliopleona armata. Non-ovigerous female, BIOICE Stn 2856: (A) habitus; (B) pleonal sternites, lateral; (C) antennule; (D) antenna; (E) uropod. Scale bars: (i) 1 mm for A; (ii) 0.5 mm for B; (iii) 0.25 mm for C–E.

Figure 6. Chauliopleona armata. Non-ovigerous female, BIOICE Stn 2856: (A) labrum; (B) left mandible molar; (C) right mandible; (D) maxillule endite; (E) maxilliped (palps omitted); (F) maxilliped palp article-2; (G) epignath; (H) cheliped; (J) cheliped propodus mesial comb and dactylus. Scale bars: (i) 0.25 mm for A–G; (ii) 0.25 mm for H–J.

Figure 7. Chauliopleona armata. Non-ovigerous female, BIOICE Stn 2856: (A–F) pereopods 1–6 respectively; (G) pleopod (setae very finely plumose, omitted for clarity). Scale bar 0.25 mm.

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.