Revision of the coral-inhabiting genus Conopea (Cirripedia: Archaeobalanidae) with description of two new species of the genera Conopea and Acasta Author Kolbasov, Gregory A. Author Chan, Benny K. K. Author Molodtsova, Tina N. Author Achituv, Yair text Zootaxa 2016 4178 2 182 208 journal article 10.11646/zootaxa.4178.2.2 2f21df88-0bd8-43ca-8f9c-7c1e57a48c3a 1175-5326 266295 D9ABE50D-4C9A-4086-BD65-F692AF81A50E Genus Conopea Say, 1822 Diagnosis (modified, see section ‘Phylogeny’): Archaeobalanids with strong, firm shells that cannot be easily disarticulated into separate compartments after separation from host; shell orifice with even summits; rostral plate often elongated in basal part along host axis; basis firmly clasping axis of host coral; outer surface of parietes smooth, lacking spines; inner surface with longitudinal ribs prominent along basal margin; radii solid, with summits parallel to basal margin of parietes and denticulated sutural margins; margin of basis with deep, rounded pits to interlock with corresponding inner ribs of parietes; scutum with simple growth ridges and truncated (sinusoid) basitergal angle; penis with developed basidorsal point. The genus Conopea includes of 20 epizoic species from tropical and temperate seas, inhabiting alcyonacean and antipatharian corals. Type species Conopea calceola (Ellis, 1758) . Conopea titani sp. nov. Figures 1–5 . Type material. Western Australia , Ningaloo Marine Park , 24°00.8'S , 113°24.5'E , st. RVS 4545/2008/D104, epibenthic sledge, coll. Drs. Salotti M.P. , Slack-Smith S . M., 0 6.02.2008, 57 m, one specimen covered by a reddish calcaxonian alcyonacean of family Ellisellidae in pure ethanol. Holotype WAM C50309 (shell compartments in ethanol, mouth parts and cirri mounted in glycerol on microscope slides) is deposited in Western Australian Museum , Perth. Two paratypes WAM C49287 are deposited in Western Australian Museum , Perth : Western Australia , Rowley Shoals , Imperieuse REEF , L23, 18 27'37''-18 27'43''S, 120°08'41''- 120°08'41''E , st. SS0507/ 0 82, coll. Drs. Gomez O.A. , Whisson C . S., 19.06.2007 , 80- 81 m . Nine paratypes WAM C43609 are deposited in Western Australian Museum , Perth : Western Australia , Adele Island Kimberley , 15 30'00''S, 123°05'00''E , st. 09/ K09-T72, coll. Dr. Gomez O.A. , Mr . Hossie A., 16.10.2009 , 14 m. Diagnosis . Shell very large, strong, elongated in both basal areas of carina and rostrum, parietes and basis solid, parietes with prominent basal ribs, margin of basis with rows of deep pits. Opercular plates thick, scutum with simple growth ridges, tergum with blunt apex and short, broad spur. Crests of labrum without teeth. Anterior rami of cirri III and IV with sharp denticles. Penis with large basidorsal point. Description . Shell very large, strong, cannot be disarticulated into separate compartments. External surface of shell smooth, covered by firmly attached, horny, brownish coenosarc of gorgonian ( Fig. 1 A). Color ivory, carina and carinolaterals 2 slightly tinted with rose, radii white, paler than parietes ( Fig. 1 B). Maximum axis length 62.7 mm , height 13.6 mm , width 16.4 mm , orifice maximal diameter 6.8 mm . Basal parts (basis, carina and rostrum) elongated in both carinal and rostral portions. Parietes with radii and alae solid ( Figs 1 C, D; 2B). Radii with rectangular summits parallel to basal margin of parietes and extending from apex to apex of adjoining plates, orifice of shell not dentate ( Fig. 1 A–C). Sutural margins of radii denticulated, striated with transverse ridges (septa) ( Fig. 1 D). Alae narrow, summits oblique. Parietes with basal ribs forming several rows of prominent outgrowths at basal margin; sheath with transverse ridges, slightly less than half total length of parietes ( Figs 1 C; 2B). Carinolatus 2 narrow, basal width 1/9 to 1/10 basal width of carinolatus 1. Basis elongated in rostro-carinal axis, boat-shaped, completely clasping thick, horny axis of gorgonian ( Fig. 1 B), solid, with numerous deep and rounded pits organized in irregular rows along margin, pits articulated with basal ribs of parietes ( Fig. 2 A, B). Scutum ( Fig. 2 C–F) triangular, width less than height, thick, color ivory, distinct growth ridges, without longitudinal striation, apex acute, occludent margin dentate, tergal margin straight, basal margin curved, basitergal corner slightly truncated. Articular ridge distinct, not prominent, ~2/3 length of tergal margin, truncated, oblique ridges in upper part, articular furrow present. Adductor ridge absent, pit of adductor muscle indistinct and shallow, pit of lateral depressor muscle shallow but distinct. Tergum ( Fig. 3 ) broad, thick, color ivory, scutal margin straight, longer than convex carinal margin, apex blunt, almost rounded, exterior with conspicuous growth ridges, spur furrow absent. Spur broad, short, corners rounded, not separated from basiscutal corner, ~2/3 width of tergum. Articular ridge low, removed from scutal margin, ~1/3 length of scutal margin, 5 faint depressor muscle crests. Labrum ( Fig. 4 A) with deep medial notch, teeth absent on crests. Mandibular palps ( Fig. 4 A) club like, long, dense setae distally, short setae along outer edge. Mandibles ( Fig. 4 B–D) with 4 teeth on cutting edge, decreasing in size from upper to lower, first, second and third teeth well separated from each other, third and fourth teeth close, tooth 3 bifid, tooth 4 with 3–4 small denticles on tip, inferior angle with 1–3 denticles, inferior margin setose. Maxillules ( Fig. 4 E, F) with 12–15 cuspidate setae of different lengths and widths along straight cutting edge, notch absent, fine setae along outer and inner edges and lateral surfaces of blade. Maxillae ( Fig. 4 G), small, bilobed, long setae on distal ovate lobes. Cirri I with unequal rami, anterior rami (10, 11 segments) considerably longer than posterior rami (9 segments), both rami covered with moderately dense setae. Cirri II with unequal rami, posterior rami (8 segments) shorter than anterior (10, 11 segments), with dense setae. Cirri III ( Fig. 5 A) with thick, unequal rami, anterior rami (11, 12 segments) longer than posterior (10 segments), several pairs of setae of different sizes along anterior edges of segments, tuft of stout setae at posterio-distal angle, segments of anterior ramus with 5–8 sharp denticles on anterior edges. Cirri IV ( Fig. 5 B) with long, subequal rami, anterior rami (18 segments), posterior (17, 21) segments, anterior edges of segments with several pairs of setae of different sizes, few setae at posterio-distal angle, several sharp denticles along anterior edges of basis and basal (1–7) segments of anterior ramus. Cirri V and VI with long, subequal rami, anterior rami (20–21 segments) and posterior (20 segments) bearing several pairs of short, long setae on anterior edges, and tuft of posterio-distal setae. Penis ( Fig. 5 C, D) long, annulated, without conspicuous setae, basidorsal point prominent. FIGURE 1. Conopea titani sp. nov. , general appearance of shell. (A) Shell covered by underlaying chitinous membrane of gorgonian coenosarc, lateral view. (B) Shell with removed underlaying chitinous membrane of gorgonian coenosarc, lateral view, axis of gorgonian indicated by arrowhead. (C) Inner surface of carinolaterals 1 and 2 showing inner basal ribs of parietes and strong articulation with basis. (D) Part of carinolatus 1 showing deticulated sutural margin of radius. Abbreviations: ba — basis, ca —carina, cl1 —carinolatus 1, cl2 —carinolatus 2, r —rostrum, ra —radius, rb —inner ribs of parietes. Scale bars in µm. FIGURE 2. Conopea titani sp. nov. , shell compartments and scuta. (A) Margin of basis showing irregular rows of deep pits for articulation with basal ribs of parietes. (B) Inner surface of carinolatus 2 showing sheath and prominent basal ribs. (C), (D) Right scutum, outer and inner view. (E), (F) Left scutum, inner and outer view. Scale bars in µm. FIGURE 3. Conopea titani sp. nov. , terga. (A), (B) Left tergum, outer and inner view. (C), (D) Right tergum, inner and outer view. Scale bars in µm. Remarks . The new species, Conopea titani , is related to species of the genus Conopea that have a strong, rigid shell with thick compartments and an elongated basis, an even orifice (not dentate), the basitergal margin of the scutum truncated and with simple growth ridges, and the penis with a developed basidorsal point. These species include C. acuta (Nilsson-Cantell, 1921) ; C. basicuneata Van Syoc, Carrison-Stone, Madrona & Williams, 2014 ; C. calceola (Ellis, 1758) ; C. cornuta ( Hoek, 1913 ) ; C. cymbiformis ( Darwin, 1854 ) ; Conopea exothobasis Van Syoc, Carrison-Stone, Madrona & Williams, 2014 ; C. fidelis Carrison-Stone, Van Syoc, Williams & Simison, 2013 ; C. galeata (Linnaeus, 1771) ; C. granulata ( Hiro, 1937 ) ; C. investita ( Hoek, 1913 ) ; C. minyrostrum Van S y oc, Carrison-Stone, Madrona & Williams, 2014 ; C. mjobergi (Broch, 1916) ; C. propriens ( Hoek, 1913 ) ; C. sabangensis Van Syoc, Carrison-Stone, Madrona & Williams, 2014 ; C. saotomensis Carrison-Stone, Van Syoc, Williams & Simison, 2013 ; C. scandens ( Pilsbry, 1916 ) ; C. sinensis (Ren et Liu, 1978) ; and C. willhearsti Van Syoc, Carrison-Stone, Madrona & Williams, 2014 . Conopea titani is most similar to C. margaretae . These two species share very large shells that are conspicuously elongated in both basal carinal and rostral portions, and are similar in the form of the opercular valves, the armament of sharp denticles on the anterior rami of cirri III and IV, and the rounded tip of the basidorsal point of the penis. However, C. titani has a solid basis and parietes, rather than secondarily filled longitudinal tubes as in C. margaretae . The articular ridge of the scutum is not prominent in C. titani but is prominent in C. margaretae . The spur of the tergum is wider in C. titani , being 2/3 the width of the basal margin and ½ width in C. margaretae ; the end is truncated in C. titani and rounded in C. margaretae , and without a furrow in C. titani but with a shallow, distinct furrow in C. margaretae . The shell of C. titani is twice the length of C. margaretae . Conopea titani was found in Western Australia , whereas C. margaretae is from the Philippines . Conopea titani also resembles C. proripiens in shell shape and the structure of the opercular valves, but the carina of C. titani is much more elongated than that of C. proripiens , and the crest of the labrum of C. titani lacks teeth. Conopea titani differs from C. minyrostrum by the more elongated basal parts of the rostrum and the carina, by the presence of a solid basis rather than one with secondarily filled longitudinal tubes, by the paler rose coloration of the shell, and by the absence of teeth on the crest of the labrum. Conopea titani differs from C. calceola , C. fidelis and C. saotomensis , which represent a complex of cryptic species ( Carrison-Stone et al. 2013 ), by the absence of a beak-shaped apex to the tergum, and denticles on the terminal end of the tergal spur. The new species can be easily distinguished from C. galeata by the absence of the unique broad, square summit of the tergum. Conopea titani differs from C. cornuta , C. cymbiformis , C. granulata , C. investita , C. mjobergi , C scandens and C. siniensis in having an extremely elongated basal part of the carina, a blunt and rounded tip to the tergum, and the absence of teeth on the crests of labrum. FIGURE 4. Conopea titani sp. nov. , mouth parts. (A) Labrum with palps. (B), (D) Mandibles. (C) Lower part of mandible (inferior angle). (E), (F) Maxillules. (G) Maxillae. Scale bars in µm. FIGURE 5. Conopea titani sp. nov. , cirri and penis. (A) Cirrus IV. (B) Cirrus IV, basis and basal segments. (C) Tip of penis. (D) Base of penis with basidorsal point. Scale bars in µm. Conopea titani represents the largest species known for the genus Conopea . The rostro-carinal basal length does not usually exceed 10 mm for most species of Conopea . The basal length of C. basicuneata is ~ 51 mm , in C. exothobasis and C. margaretae it is~ 33 mm , and in some specimens of C. cymbiformis and C. galeata it may reach ~ 20–25 mm ( Darwin 1854 ; Broch 1931 ; Rosell 1991 ), but it never reaches the extreme size of 63–83 mm of the basal length that is characteristic of C. titani . Etymology . The specific name titani , from the Greek titan ( ΤΙτάν ) meaning giant, represents the size of this species, it being the largest known species of this genus.