Chthamalus Ranzani 1817
Creators: name: Chan, Benny K. K.
name: H.-N. Chen
name: P. R. Dando
name: A. J. Southward
name: E. C. Southward
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Sessilia
Chthamalidae
Chthamalus

description: <i>Chthamalus panamensis</i> Pilsbry, 1916 Figs 2E and 2F and 18–22 <b> <i>Chthamalus panamensis</i> Pilsbry, 1916:</b> pp 319–320, Plate 75 fig 2–2e [2] <b>Specimens examined.</b> ANSP(Crustacea)-2008, type collection of 7 syntypes deposited by Pilsbry 1916, Quarantine Island, Panama (= Naos Island), the intact specimen illustrated in Pilsbry’ s Plate 75, fig 2a is selected by the present authors as the Lectotype; AJS-1970. 12 specimens, rock ledges, Balboa Statue, Panama City, Panama. 8° 58.1' N, 79° 32' W, 31 Oct 1970; PWG-1, 10 specimens, intertidal rocks, 200 m N of Naos Island on the west side of Avenida Amador, 8°58.12' N, 79° 31.81' W, 3 Feb 1979. Diagnosis. <i>Chthamalus</i> with a deep longitudinal furrow on outer surface of the tergum, scutal margin of tergum straight. Bidenticulate setae absent from cirrus I. Outer surface of anterior ramus of cirrus I with a longitudinal array of setae. Cirrus II, distalmost segment of both anterior and posterior rami bears bidenticulate setae with basal guards, anterior ramus of cirrus III is about 1.5 times longer than the posterior ramus. Tergoscutal flaps orange. COI sequence (Gene Bank Numbers: KU356706—KU356708). Description. Shell pink to purple in unbleached or uneroded specimens, otherwise white, with six plates (Figs 2E and 2F and 18A and 18B). Surface with ribs extending to the apex. Orifice elliptical. Scutum and tergum articulated slightly obliquely. Scutum triangular, basal margin twice the length of the tergal margin, external surface with horizontal growth lines, and the upper portion often eroded, tergal margin with shallow articular ridge, not extending beyond the tergal margin, occludent margin straight to slightly convex, with teeth on proximal 1/3 of the margin in uneroded specimens (Fig 18C and 18D). Adductor muscle pit oval, not extending to basal margin. Lateral depressor muscle pit deep and smooth (Fig 18D–18F). Tergum triangular to trapezoid, external surface with horizontal striations and a deep longitudinal furrow is visible in the basal region (Fig 18D–18F). Such a furrow can be observed from above through the orifice of uneroded, undissected specimens (Fig 18A and 18B). Inner surface of tergum smooth, scutal margin straight, spur flat and not obvious, depressor muscle crests 3–4 (Fig 18). The original description of <i>Chthamalus panamensis</i> Pilsbry, 1916, (pp. 219–320 and Plate75 fig 2, 2a, 2b, 2c, 2d and 2e) describes only the shell and opercular plates (also see Fig 18B). Pilsbry’ s figure of the exterior of the tergum (Plate 75 fig 2e) is closely similar to the exterior of terga in our new material. The following description of the arthropodal characters is based on new material [Avenida Amador, Naos Island]. Quantitative data on segments counts in cirrus I-III were based on five specimens collected from Avenida Amador, Naos Island (PWG-1). Segment counts on cirri IV-VI were based on a single specimen from Avenida Amador, Naos Island (PWG-1) (Table 4). Cirrus I: posterior ramus 5- to 7-segmented, anterior ramus 6- to 8-segmented, outer surface with a longitudinal array of long setae, with almost one seta per segment, serrulate setae common on both rami (Figs 19A and 19B and 20A–20D). Cirrus I without bidenticulate setae (absent from all specimens examined), pappose setae on basipodite (Fig 20E). Cirrus II: posterior ramus 5 to 7 segments, anterior ramus 6 to 8 segments (Figs 19C and 20G), the most distal segment of each ramus with bidenticulate setae with basal guards, serrulate setae common on both rami (Figs 19C and 19D and 20G–20I, Table 4). Pappose setae on basipodite (Fig 20J and 20K). Cirrus III: posterior 12- to 16-segmented, anterior ramus 16- to 22-segmented, 1.4 to 1.5 times the length of the anterior ramus (Fig 19E), intermediate segments bear 3 pairs of long and 1 pair of short setae (Figs 19E and 20L–20N). Cirrus IV: anterior and posterior rami similar in length (Fig 19F), anterior and posterior rami 16 segmented (Figs 19F and 20O and 20P). Cirrus V: anterior and posterior rami 16-segmented (Fig 19G). Cirrus VI: anterior ramus 19-segmented, posterior ramus 20-segmented (Figs 19H and 20Q). The intermediate segments of cirri IV-VI bear three pairs of long and one or two pairs of short simple setae (Figs 19F–19H and 20S and 20R). Maxilla bilobed, with dense serrulate setae on each lobe (Figs 21A and 22A–22C). Maxillule notched, notch weak, two large setae above notch, 10 setae below notch (Figs 21B and 22D and 22E). Mandible has 4 major teeth, second to fourth teeth bidenticulate, pecten with 21 very small teeth, inferior angle tipped with 3 pointed teeth (Figs 21C and 21D and 22F–22K). Mandibular palp rectangular, with long simple setae on tip and serrulate setae on superior margin (Figs 21E and 21F and 22L, 22M and 22N). Labrum concave, with 6 or 7 small fine teeth on cutting edge (Figs 21G and 21H and 22O and 22P). Penis without basi-dorsal point. <b>Distribution.</b> Pacific coast of Central America from about 14° N to 8° 15' N (southern limit unknown). Remarks. Specimens of <i>C</i>. <i>panamensis</i> collected for the present study agreed with the syntypes of <i>C</i>. <i>panamensis</i> described by Pilsbry [2] in having a deep groove on the outer surface of the tergum, which is the key diagnostic feature of <i>C</i>. <i>panamensis</i>. This morphological feature of the tergum was also reported in Pitombo &amp; Burton [12]. The sympatric <i>C</i>. <i>newmani</i> sp. nov is distinguishable from <i>C</i>. <i>panamensis in situ</i> by its lack of deep tergal grooves. In addition, it has has brown tergo-scutal flaps while those of <i>C</i>. <i>panamensis</i> are orange. The flaps are visible in the living barnacle when the orifice is open under water (Fig 2E and 2F). Arthropodal character differences are: Cirrus I of <i>C</i>. <i>newmani</i> has bidenticulate setae, Cirrus I of <i>C</i>. <i>panamensis</i> does not. Cirrus III of <i>C</i>. <i>newmani</i> has equal rami. Cirrus III of <i>C</i>. <i>panamensis</i> has unequal rami. This feature of cirrus III in <i>C</i>. <i>panamensis</i> was not reported by Pilsbry [2] or Pitombo &amp; Burton [12].
description: Published as part of <i>Benny K. K. Chan, H. - N. Chen, P. R. Dando, A. J. Southward &amp; E. C. Southward, 2016, Biodiversity and Biogeography of Chthamalid Barnacles from the North-Eastern Pacific (Crustacea Cirripedia), pp. 1-51 in PLoS ONE 11 (3)</i> on pages 29-35, DOI: 10.1371/journal.pone.0149556, http://zenodo.org/record/1161582
description: {"references": ["2. Pilsbry HA. The sessile barnacles (Cirripedia) contained in the collections of the U. S. National Museum; including a monograph of the American species. U. S. National Museum Bulletin no. 93: 1 - 366.", "12. Pitombo FB, Burton R. Systematics and biogeography of Tropical Eastern Pacific Chthamalus with descriptions of two new species (Cirripedia, Thoracica). Zootaxa. 2007; 1547: 1 - 30."]}