Dorphinaxius kermadecensis ( Chilton, 1911 )

Poore, Gary C. B. & Collins, David J., 2009, Australian Axiidae (Crustacea: Decapoda: Axiidea), Memoirs of Museum Victoria 66 (2), pp. 221-287 : 254-255

Dorphinaxius kermadecensis ( Chilton, 1911)

Figures 21–23

Iconaxiopsis kermadecensis Chilton, 1911: 550–551 , figs. 1, 2. Axius (Eiconaxius) kermadecensis . — De Man, 1925b: 4, 10, 15. Axiopsis (Paraxiopsis) appendiculis Poore and Griffin, 1979:

224–226, fig. 1. Eiconaxius kermadecensis .— Sakai and de Saint Laurent, 1989: 23. Dorphinaxius appendiculis .— Sakai and de Saint Laurent, 1989:

34.— Sakai, 1994: 200. Dorphinaxius kermadecensis .— Davie, 2002: 452.— Poore, 2004:

175, figs. 45e, f, 46c.

Material examined. Iconaxiopisis kermadecensis Chilton, 1911 . Syntypes. New Zealand, Kermadec Islands , Meyer I. and Coral Bay, rock pools at Sunday I. [= Raoul I.] (29°16’S, 177°55’W), Captain Bollons, BMNH 1912.5.25.44–46 (fragments of 5 chelipeds, 1 body with only abdominal segments identifiable, 1 body with anterior carapace, 1 right uropod; annotated “Cotypes Pres. Prof. Chilton. The specimenscamebackfromGodstoweverymacerated—onlyfragments left. I. G[ordan] v/46.”).

Axiopsis (Paraxiopsis) appendiculis Poore and Griffin, 1979 . Holotype. Australia, NSW, Shellharbour, under stones between tide marks, G. McAndrew, 1926, AM P9359 (ovigerous female, cl. 14 mm). Paratypes. Australia, central NSW: Grafton , Collaroy , Port Jackson and Shellharbour (29°47.0’S – 34°35’S, 151°12’E – 153°18’E), AM, 12 of 19 paratype lots (6 males, cl. 10–19 mm; 14 females, 6 ovigerous, cl. 6.5–21 mm).

Other material. Australia, Norfolk I., Emily Bay , Point Hunter (29°03.8’S, 167°57.3’E), 0–0.25 m, H. Larsen, 18 Apr 1984, NTM Cr001666 (juvenile, cl. 4.0 mm) .

Description. Carapace smooth except for slight rugosity at base rostrum, with few setae on gastric region and rostrum. Rostrum 0.25 times length of front-to-cervical groove, broadly triangular, without or with 2 or 3 lateral tubercles anterior to supraocular spine, depressed below level of median carina, anteriorly directed or directed slightly upwards, continuous with lateral carinae. Supraocular spines prominent, broadly triangular. Lateral carina unarmed. Submedian carina smooth, with 1 anterior blunt tooth. Median carina obsolete, with single tooth, sloping down at 20–40°. Abdominal somite 1 pleuron ventrally rounded; pleuron 2 asymmetrical, posteriorly rounded; pleura 3–5 rounded; pleura 6 rounded.

Eyestalk, 0.5 length of rostrum; cornea pigmented. Antennular peduncle reaching to midpoint of antennal article 4; article 1 with mesial and distal spinule. Antennal article 1 unarmed; article 2 stylocerite obsolete; scaphocerite one third length of article 4, curved downwards; article 4, 1.5 times length of article 2; article 5 about half length of article 4. Maxilliped 3 coxa and basis lower margin each with distal spine; ischium unarmed; crista dentata of about 17 teeth; merus with 3 spines; carpus with 1 spine.

Pereopods 1 asymmetrical, robust, not sexually dimorphic. Major cheliped coxa to ischium unarmed; merus upper margin strongly convex, unarmed, lower margin with 1 small spine; carpus unarmed; propodus unarmed; fixed finger 0.5 times as long as upper palm, cutting edge with 1 triangular tooth; dactylus distally curved, cutting edge unevenly toothed.

Minor cheliped similar to major, propodus narrower, fixed finger 0.6 times as long as upper palm, cutting edge with 2 blunt teeth.

Pereopod 2 ischium lower margin unarmed; merus lower margin unarmed; carpus slightly shorter than chela; propodus upper margin 1.1 times length of dactylus. Pereopod 3 merus unarmed; propodus 2.0 times as long as dactylus, with 5 transverse rows each of 3–9 robust setae; dactylus tapering, with 8 large robust setae plus longitudinal row of 7 smaller robust setae on inner face, plus unguis. Pereopod 4 propodus 2.4 times as long as dactylus, distally densely setose, with 5 transverse rows each of 3–10 robust setae; dactylus tapering, with 11 large robust setae plus longitudinal row of 7 smaller robust setae on inner face, plus unguis. Pereopod 5 propodus 2.5 times as long as dactylus, weakly subchelate, distally densely setose, with distal transverse row of 7 robust setae; dactylus spoon-shaped, with 2 robust setae mesially, plus unguis.

Pleopods 2–5 each with appendix interna 0.2 length of endopod. Pleopod 1 of male absent. Pleopod 2 of male appendix masculina 1.1 times as long as appendix interna. Pleopod 1 of female a single narrow article.

Telson 1.2 times as long as wide, widest proximally, then tapering, lateral margin with 4 teeth and 2 robust setae, distal margin convex between distolateral spines and robust setae, without posteromedian spine; dorsal face with oblique ridges bearing 2 spines. Uropodal endopod 1.7 times as long as wide, with 3 or 4 lateral spines, longitudinal ridge with 2–4 spines (last submarginal). Uropodal exopod 1.5 times as long as wide, with 3 or 4lateral spines, longitudinal rib with 3 or4 spines,posterolateral angle with 1 fixed spine and 1 robust seta; transverse suture 3–5 spines, two most medial strongest, adjacent and diverging.

Distribution. New Zealand: Kermadec Is; Australia: Norfolk I., central NSW. Intertidal to 8 m depth.

Remarks. Chilton (1911) based his new species on “several specimens,” the largest with a carapace length of 17 mm and abdomen to end of telson, 29 mm. The “cotypes” at the BMNH are the remains of only three specimens; no material could be found at the Canterbury Museum, Christchurch, New Zealand, where Chilton placed other species, nor at the National Museum of New Zealand (Te Papa). His description was brief, mentioning only the rostrum, the gastric region of the carapace and the chelipeds; he illustrated only the left and right chelipeds of one individual.Helikenedthespeciesto “ Iconaxiopsis ” andamanensis Alcock, 1901 now placed in Eiconaxius Bate, 1888 .

In his key, De Man (1925b) correctly assumed that the species possessed pleurobranchs and placed it in the subgenus Axius (Eiconaxius) . Sakai and de Saint Laurent (1989) failed to report the pleurobranchs above pereopods 3–4 of the species they called D. appendiculis in spite of having examined material and noting their presence in the generic diagnosis.

The synonymy of I. kermadecensis and A. appendiculis was first proposed by Davie (2002) on the advice of the late Brian Kensley but we are unaware of how he reached this conclusion. We have carefully examined what remains of the types of I. kermadecensis and compared them with types of A. appendiculis , both reillustrated here. We can detect no differences and agree with Kensley. The attitude of the rostrum varies remarkably (cf. figs. 22a, g), as does the number of lateral spines on the uropodal rami. A submedian tubercle sits between those on the median and lateral gastric carinae on some specimens, for example, on three of six individuals in one sample. The difference is not of taxonomic significance.

Although the species occurs at the Kermadec Islands north of New Zealand, at Norfolk Island in the Tasman Sea, and in the Sydney region, Australia, it has not been recorded from the main islands of New Zealand (S. Ahyong, R. Webber, pers. comm.).

Figures

Figure 21. Dorphinaxius kermadecensis (Chilton, 1911). Fragments of 5 chelipeds, abdominal segments, anterior carapace, rami of right uropod. All from syntypes of Iconaxiopisis kermadecensis Chilton, 1911. BMNH 1912.5.25.44–46. Top scale bar refers to carapace, abdomen and uropod; bottom scale bar refers to chelipeds.

Figure 22. Dorphinaxius kermadecensis (Chilton, 1911). a, lateral view. b, dorsal view of carapace, peduncles of antennule and antenna. c, telson and right uropod. d, epistome, bases of right antennule and antenna (ventral). e, major pereopod 1 (right, lateral). f, minor pereopod 1 (left). g, lateral anterior carapace and rostrum. a–f from holotype of Axiopsis (Paraxiopsis) appendiculis Poore and Griffin, 1979 (AM P9359, ovigerous female, cl. 14 mm); g from female, cl. 21 mm (AM P1511).

Figure 23. Dorphinaxius kermadecensis (Chilton, 1911). a, maxilliped 3. b–e, pereopods 2–5. f, g, female pleopods 1, 2. h, male pleopod 2. a–g from holotype of Axiopsis (Paraxiopsis) appendiculis Poore and Griffin, 1979 (AM P9359, ovigerous female, cl. 14 mm). h from male, cl. 19 mm (AM P18557).