Vulcanolepas buckeridgei, Chan & Chang, 2018

Chan, Benny K. K. & Chang, Yen-Wei, 2018, A new deep-sea scalpelliform barnacle, Vulcanolepas buckeridgei sp. nov. (Eolepadidae: Neolepadinae) from hydrothermal vents in the Lau Basin, Zootaxa 4407 (1), pp. 117-129 : 119-124

Vulcanolepas buckeridgei sp. nov.

( Figures 2–6 )

Vulcanolepas Lau A. Southward & Newman, 2008: 260 , fig. 1, fig. 2e, f, tab. 1 Vulcanolepas sp. 1. Herrera et al. 2015: fig. 2

Material examined. Holotype. MNHN-IU-2014-50277. Stn. Lau Basin 2005_JD-164, Lau Basin, Kilo Moana (22° 0' 0'' S, 176° 0' 0'' W, 26 June, 2005, depth 2628 m). Coll. Hourdez, S. Paratype. MNHN-IU-2014-5282 (damaged specimen). Stn. Lau Basin 2006_JD-235, Lau Basin, Kilo Moana (22° 0' 0'' S, 176° 0' 0'' W, 16 September, 2006, depth 2629 m). Coll. Hourdez, S.

Diagnosis. Vulcanolepas with basal angle of tergum elevated from the capitular-peduncular margin by ~1/6 of capitular height.Mandible tridentoid; cutting margin of second and third teeth long, each with 18–20 sharp spines. Proximal segments of anterior and posterior rami of cirrus I protuberant and with dense simple setae.

Description (based on holotype). Hermaphrodite capitulum higher than wide; 8 approximate plates, spaces between plates occupied by thin cuticular membranes. Carina umbo apical, slightly bowed, surface with 6 horizontal growth lines; height of carina 2/3 height of capitulum ( Figure 2 ). Tergum quadrangular with single ridge extending from basal angle toapex; surface with V-shaped growth lines; basal angle of tergum slightly elevated from capitular-peduncular edge, at ~1/6 total height of capitulum ( Figure 2 ). Scutum quadrangular, basal angle ~70°, located at capitular-peduncular edge; umbo apical; apex retro-curved ( Figures 2 , 3 ). Medial latus equilateral triangular, umbo apical, surface with 7 straight, horizontal growth lines. Rostrum triangular, 7 horizontal growth lines on surface.

Capitular:peduncular ratio ~1:1 ( Figure 2 ). Peduncle with 23 scales/whorl just below capitular region, 24 scales/whorl at mid region of peduncle, scale width 0.87 mm (average from 3 scales), 0.73 mm (average from 3 scales) projecting from peduncle. Scales smaller at capitular region, becoming larger at basal region of peduncle. Internallly, capitular plates white, smooth ( Figure 3A ).

All six pair of cirri located close to each other, without first pair being separated ( Figure 3B ). Cirrus I with anterior and posterior rami similar in length, segments close to proximal region with width 2 x greater than length, rami becoming antenniform distally, with length 2 x greater than width ( Figure 4A ). Last 5 proximal segments of anterior and last 7 proximal of anterior ramus of cirrus I protuberant, bearing dense, simple setae ( Figures 4A , 5A– D ). Cirrus II with rami similar in length; proximal last 4–10 segments protuberant, with denser, simple setae ( Figure 4B ). Intermediate segments of cirrus II bearing 2 pairs of long setae and 3 pairs of short simple setae. Cirrus III with anterior and posterior rami similar in length, bearing very long setae, length of setae ~ 10 x length of individual segment; setae serrulate with very short, sparse setules, surface coated by filamentous bacteria ( Figure 4C ). Cirri IV–VI similar, with anterior and posterior rami similar length; distal segments of both rami with width two x greater than height ( Figure 4D–F ); setae long, ~ 10 x length of individual segment; intermediate segments of cirri IV to VI bearing 1 pair of short setae and 4 pairs of long setae. Caudal appendage unsegmented, short, blunt, length ~1/8 length of pedicel of cirrus VI ( Figure 4G ). Penis without basi-dorsal point, half length of cirrus VI ( Figure 4H ).

Maxilla subtriangular, with simple type setae on exterior margin ( Figure 5E, F ). Maxillule cutting edge straight, with dense, simple setae on cutting margin; interior margin slightly convex ( Figure 5G, H ). Mandible tridentoid; first tooth small, robust, sharp, separated from remainder ( Figure 6A–F ). Second and third teeth combshaped, 18–20 sharp spines on cutting edge. Cutting edge of second and third teeth long, each occupying 1/3 total length of mandible; inferior angle blunt, composed of series of sharp, large spines ( Figure 6D ). Mandibular palp elongated, with simple setae on tip and outer margin ( Figure 6G ). Labrum not bullate, with small, concave notch; single array of small, sharp teeth at notch ( Figure 6H ).

Etymology. Named in honour of Professor John S. Buckeridge (RMIT University, Melbourne, Australia) for his contribution to the taxonomy of hydrothermal vent stalked barnacles in the family Eolepadidae .

Distribution. Lau Arc Basin.

Remarks. The present study contributes the fourth species to Vulcanolepas . All four Vulcanolepas species have distinct morphological diagnostic characteristics. Both the mandible of V. buckeridgei sp. nov. and V. parensis Southward, 2005 are tridentoid, but the first tooth of V. parensis is much larger than the first tooth in V. buckeridgei sp. nov. In addition, V. buckeridgei sp. nov. has very long second and third mandibular teeth, each tooth taking 1/3 of the total length of the mandible, and each tooth bearing 18–20 spines on the cutting edge. In V. parensis , the length of the second and third teeth is ~1/7 of the total length of the mandible. The inferior angle of the mandible of V. scotiaensis contains dense setae, whilst the inferior angle of V. buckeridgei sp. nov. has several sharp spines, without any setae. The mandibles of V. oshaei have four teeth, differing from the other three Vulcanolepas species. Cirrus I of V. buckeridgei sp. nov. has protuberant segments at the basal region of both the anterior and the posterior rami. Protuberant segments are not reported in the other three species of Vulcanolepas .

Figures

FIGURE 2. Vulcanolepas buckeridgei sp. nov. (holotype). A. Left view, B. Right view, C. Rostral view, D. Carinal view of whole specimens. T—tergum, S—scutum, R—Rostrum, C—Carina. White arrows indicate the basal angle of the tergum, which is elevated above the capitular-peduncular interface.Scale bars in cm.

FIGURE 3. Vulcanolepas buckeridgei sp. nov. (holotype). Dissected individual showing the internal face of the capitulum (S—scutum, T—tergum,ML—medial latus). B.somatic bodyshowing the six pairs of cirri(I–VI) and caudal appendage (CA). Note the six pairs of cirri are located close to each other, without the firstpairs being separated from other pairs of cirri, as seen in most scalpellomorph species. Scale bars in cm.

FIGURE 4. Vulcanolepas buckeridgei sp. nov. (holotype). A. Cirri I. B. Cirrus II. C. Cirrus III. D. Cirrus IV. E. Cirrus V. F. Cirrus VI. G. Caudal appendages (CA, indicated by arrow). H. Penis. Scale bars in µm. ant—anterior ramus, pos—posterior ramus.

FIGURE 5. Vulcanolepas buckeridgei sp. nov. (holotype). A. magnified view of protuberant segments of the posterior (pos) and anterior rami (ant) of cirrus I. B. Simple setaeof the anteriorramus of cirrus I. C. Serrulate setae of anterior ramus of cirrus I. D. Distal segments of anterior ramus of cirrus I E. Maxilla. F. Serrulate setae on the cutting margin of the maxillule. G. Maxillule.H. simple robust setae on the cutting edge of the maxillule.Scale bars in µm.

FIGURE6. Vulcanolepas buckeridgei sp. nov. (holotype).A. Right mandible B. Serrated teeth on mandular cutting margin. C. Spine behind the first tooth. D. Inferior angle of mandible. E. Left mandible. F. Magnified view of serrated teeth on cutting margin. G. Mandibulatory palp.H.Labrum.Scale bars in µm.