Darryllianassa felderi, Poore, 2023

Poore, Gary C. B., 2023, New records, one new genus and 21 new species of Callianassidae (Crustacea, Axiidea) from the Indo-West Pacific, Memoirs of Museum Victoria 82, pp. 167-255 : 197-200

Darryllianassa felderi sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:FC91087C-2DC4-

4E01-B5A1-919D4CDF750C

Figures 22 , 23

Material examined. Holotype. Papua New Guinea. Madang Province, Alexishafen , 05° 05.3' S, 145° 48.0' E, 8–13 m ( PAPUA NIUGINI stn PS14 ), MNHN IU-2017-1354 (female, 4.3 mm).

Description of female holotype. Rostrum triangular, situated at level of dorsal carapace, 0.65 length of eyestalk. Carapace well calcified, dorsally almost flat in lateral view, 1.3 times as long as pleomeres 1–2 combined; orbital margin oblique, convex; anterolateral lobe triangular; subanterolateral margin convex, oblique; anterior margin of branchiostegite with dorsal concavity, produced as narrow rounded lobe; cervical groove deeply incised, across 0.8 length of carapace, not reaching linea thalassinica. Pleomere 1 tergite without transverse groove, much narrower anteriorly. Pleomere 2 1.25 times as long as pleomere 1. Pleomere 5 slightly longer than pleomeres 3 and 4. Pleomere 6 about as long as pleomere 5, about as long as wide anteriorly.

Eyestalk slightly longer than wide, with dorsal face scarcely depressed anteriorly, proximally swollen, with sharp convex anterolateral margin, anteromedial angle sharply rounded in dorsal view, not overreaching distal margin of antennular peduncle article 1. Cornea densely pigmented, occupying small mid-distal area of eyestalk.

Antennular peduncle little shorter than antennal peduncle; article 1 visible in dorsal view only laterally; article 3 about as long as articles 1 and 2 combined; article 2 with few long setae; article 3 with few well-spaced ventrolateral setae. Antennal peduncle article 5 0.55 times as long as article 4; scaphocerite acute.

Mandible well calcified; molar process with doubletoothed margin; incisor with triangular teeth. Other mouthparts typical of family (fig. 23h–n). Maxilliped 3 ischium not narrower distally, 1.8 times as long as wide, crista dentata comprising 5 strong independent curved teeth over proximal half, 8 smaller closer teeth forming blade over distal half; merus 0.5 times as long as ischium measured along outer margin, slightly wider than long, wider than ischium, with mesiodistal margin almost transverse, separated from rounded inner margin by obtuse rounded corner; carpus as long as merus outer margin; propodus ovoid-tapering, 1.7 times as long as wide; dactylus tapering, shorter than propodus, with scattered setae along upper margin, dense row of short setae along distal lower margin.

Pereopods 1 (chelipeds) subequal in size, similar. Major cheliped carpus-palm upper margin 0.65 carapace length. Ischium scarcely expanding distally, upper margin straight, unarmed; lower margin with row of 3 similar spines. Merus 0.9 length of ischium, 1.9 times as long as wide (tooth excluded), ovate; upper margin convex, unarmed; lower margin with oblique spine near midpoint. Carpus 1.45 times as long as wide; upper margin with soft rounded ridge; lower margin carinate. Propodus upper margin 0.75 length of carpus; palm length 0.8 width; upper margin convex in lateral view, rounded; lateral surface smooth, convex, with slight ridge running along fixed finger, setose above this ridge; distolateral margin of palm produce, with 2 blunt teeth in gape; mesial surface convex, distomesial margin concave, set back from distolateral margin, with small tooth; lower margin carinate, with row of setae extending onto fixed finger; fixed finger 1.5 times as long as palm, tapering, with upturned tip; major cutting edge lateral, straight with regular row of 8 small triangular teeth, with more medial smooth ridge separated from major ridge by shallow groove and deep cavity at base (under dactylus). Dactylus as long as fixed finger, curved, with acute tip; upper margin ridged, with tufts of long setae; cutting edge doubly carinate, lateral carina with 3 small triangular teeth.

Minor cheliped essentially similar to major cheliped, 0.95 length. Ischium lower margin with 2 spines. Palm distolateral margin with 1 triangular tooth.

Pereopod 2 merus lower margin slightly sinusoidal, 3.0 times as long as wide; carpus about 1.6 times as long as wide; chela subtriangular; palm about 1.8 times as wide as upper margin; dactylus 2.7 times as long as palm upper margin. Pereopod 3 carpus 2.7 times as long as wide; propodus oval, 1.6 times as long as wide; lower margin without proximal heel, with long subdistal spiniform seta. Pereopod 4 coxa flattened ventrally, distal articles linear. Pereopod 5 chelate.

Pleopod 1 uniramous. Pleopod 2 biramous, exopod shorter than endopod. Pleopod 3 appendix interna emerging from endopod margin.

Uropod endopod and exopod overreaching posterior margin of telson. Endopod elongate-oval, widest near midpoint, twice as long as wide; upper surface without spiniform setae; anterior margin almost straight; distal margin evenly convex, with 1 short spiniform seta plus cluster of submarginal fine setae; posterior margin setose. Exopod subrectangular, 1.6 times as long as wide, exceeding endopod by one third its length; anterior margin straight; all margins with numerous slender setae, with about 12 blade-like setae on posterior margin indistinguishably merged with distal margin; dorsal plate reaching about halfway across exopod, of about 15 stiff setae; dorsal surface with 2 long setae and 1 small spiniform seta near distal anterior margin.

Telson 0.9 times as wide as long, broadest anteriorly, narrowing posteriorly to broadly rounded posterolateral corners; anterolateral lobes ventral to (overlapping) posterolateral margin; posterolateral corners each with 2 spiniform setae; posterior margin excavate, with minute median tooth; dorsal surface with few medial setae in row at 0.3 length.

Etymology. For Darryl L. Felder, University of Louisiana at Lafayette, Lafayette, Louisiana, honouring his considerable contribution to callianassid taxonomy and ecology, and his part in the study leading to this contribution.

Distribution. Eastern Coral Triangle ( Papua New Guinea); 8–13 m (known only from type locality).

Remarks. The species is the only one in the genus and is immediately recognised by its equal chelipeds, each with fingers longer than the palm and with a deep groove and basal cavity on the cutting edge of the fixed finger.

Figures

Figure 22. Darryllianassa felderi sp. nov. Papua New Guinea. MNHN IU-2017-1345, holotype female, 4.3 mm. a, eyestalks, carapace, pleon, telson, uropod; b, eyestalk, carapace, pleomeres 1, 2; c, d, anterior carapace, eyestalk, antennular, antennal peduncles (lateral, dorsal); e, pleomere 6, telson, right uropod; f, major cheliped (left, mesial); g, major cheliped propodus, dactylus (lateral); h, major cheliped carpus–dactylus (upper view); i, minor cheliped (left, mesial); j, minor cheliped propodus, dactylus (lateral). Scale bars = 1 mm.

Figure 23. Darryllianassa felderi sp. nov. Papua New Guinea. MNHN IU-2017-1345, holotype female, 4.3 mm. a–d, pereopods 2–5; e, mandible (posterior view); f, mandible molar, incisor processes; g, mandibular palp; h, maxillule; i, maxilla; j, maxilliped 1; k, maxilliped 2; l, maxilliped 3 (inner view); m, maxilliped 3 (outer view); n, maxilliped 3 crista dentata (mesial view); o–q, pleopods 1–3. Scale bars = 1 mm.