Alima pacifica Ahyong, 2001

Feller, Kathryn D., Cronin, Thomas W., Ahyong, Shane T. & Porter, Megan L., 2013, Morphological and molecular description of the late-stage larvae of Alima Leach, 1817 (Crustacea: Stomatopoda) from Lizard Island, Australia, Zootaxa 3722 (1) : -

Alima pacifica Ahyong, 2001

( Fig. 4 )

Material examined. Alima pacifica last stage larva; NE side of Lizard Island, Queensland, Australia; intertidal, collected at night by M.L. Porter and K.D. Feller; 1 June, 2012. All measurements and drawings reported in text are from a single reference specimen ( KF205338 , P.90967). Other specimens ( KF205339 , P.90965; KF205340 , P.90968; KF205341 , P.90964) are included in Table 1 for mean character measurements.

Description. Last larval stage 42.9 mm in total length. Carapace length 17.2 mm, with posterior edge terminating at thoracic somite 6; strong posterolateral spines extending to thoracic somite 8; anterior spine extending to the antennule flagella, 4.7 mm in length; 2 anterolateral spines, extending to base of eyestalks; short, dorsally directed spine placed on hump near posterior margin of carapace; lateral margins of carapace straight or convex, with 12 ventral spinules along each margin; carapace width 5.4 mm.

Eyestalks elongated; evidence of larval, adult retinae inferior to single cornea. Adult retina with visible midband emerging medial to larval retina.

Antennules with 3-segmented stalk, 3 setiferous flagella, lower 2 shortest. Antenna with stalk elongated, scale lying lateral to anterolateral angles of carapace; flagellum present.

Maxillipeds 1–5 well developed, first 2 elongated, last 3 short, all segments developed; maxillipeds 1–4 with epipod. Maxilliped 2 with spine on basal portion; propodus 8–9 times as long as deep, distal portion of upper margin pectinate; dactylus unarmed, 6 teeth visible under cuticle.

Thoracic somites elongated, not armed posterolaterally. Pereopods 1–3 well developed. Abdominal somites 1– 5 with posterolateral angles each drawn into strong upcurved spine; each somite with pair of well-developed pleopods; pleopods with gill buds.

Abdominal somite 6 dorsally with submedian spines only; with strong spine anterior to uropodal articulation; somite 6 not separated laterally from telson, demarcation visible mid-dorsally; outline of postlarval somite 6 clearly visible through cuticle.

Uropods well developed, with 3 to 4 teeth on outer margin of penultimate segment of exopod, last 1 or 2 spines free. Uropodal protopod with inner spine longer than outer, without distinct lobe between spines but with 2 rounded lobes of postlarva clearly visible through cuticle.

Telson 2.3 times as long as wide (average), without median carina or dorsal spine. Larval denticles with apices fixed: submedian 12–15, intermediate 15–19, none lateral. Postlarval denticles, movable apices of submedian teeth clearly visible through cuticle, about 2 submedian denticles present for every postlarval denticle; larval to adult intermediate denticles present in ratio of 1:1.

Coloration. As in A. orientalis , all A. pacifica non-retinal tissue in observed specimens is completely transparent with red, iridescent colored patches along edges of raptorial appendages and abdominal segments ( Fig. 5 ).

Remarks. The last larva can be distinguished by the presence of postlarval features beneath the larval cuticle; these include the postlarval carapace, raptorial dactylus, telson

armature and uropod structure.

Figures

FIGURE 4. Alima pacifica last-stage larval type (specimen B, KF 205338, P. 90967); total length 42.5 mm. A, ventral habitus. Eyes possess both larval and developing adult retinas. Larval retina is lateral, hatched-shaded structure. B, ventral lateral edge of carapace. C, enlarged view of uropod and telson. D, dorsal view of telson and insipient separation of 6 th abdominal somite. E, lateral view of carapace. Key character identifiers same as listed in Fig. 3, indicated with arrows. All scale bars 1 mm.

FIGURE 5. Epi-illuminated (A, D) and trans-illuminated (B, C) photographs of last stage A. pacifica (A, B) and A. orientalis (C, D). Arrows in A and D indicate patches of red coloration. Scale bar 1 mm for all panels.