Caecum galapagoense, Raines, 2020
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publication ID |
https://doi.org/ 10.11646/zootaxa.4827.1.1 |
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publication LSID |
lsid:zoobank.org:pub:2CE528C2-DE07-4155-B37D-BE2C342A3901 |
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DOI |
https://doi.org/10.5281/zenodo.4453338 |
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persistent identifier |
https://treatment.plazi.org/id/03A3DF49-FF66-FF04-FF44-FA32FE793F5C |
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treatment provided by |
Plazi |
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scientific name |
Caecum galapagoense |
| status |
sp. nov. |
Caecum galapagoense View in CoL species novum
Figures 117 View FIGURE 117 A–H, 118A–M, 119A–B, 128B
Type material. Holotype, LACM 3754 View Materials ; paratypes, LACM 3755 View Materials (6 figured, 4 unfigured); SBMNH 637744 View Materials (3 figured, 1 unfigured); SBMNH 637745 View Materials (5 unfigured).
Additional material examined. NHMLAC: LACM 1984 View Materials - 47.16 View Materials , Academy Bay , Indefatigable Island, Galapagos Islands, Ecuador, intertidal to 1 m, 10 sh ; LACM 1972 View Materials - 196.28 View Materials , Espinoza Point , Fernandina Island, Galapagos Islands, 15–30 m, 8 sh . SBMNH: SBMNH 637744 View Materials , Cousins Rock , Galapagos Islands, Ecuador, 17–20 m, 1 sh ; SBMNH 618589 View Materials , Española Island (Hood), Galapagos Islands, Ecuador, 18 m, 7 sh ; SBMNH 637745 View Materials , Cormorant Point , Floreana Island, Galapagos Islands, Ecuador, intertidal, 2 sh .
Type locality. Academy Bay , Indefatigable Island, Galapagos Islands, Ecuador .
Diagnosis. Teleoconch subcylindrical, with slight increase in diameter from posterior end to aperture. Surface translucent white, glossy, sculptured with orange peel texture. Axial ribbing present posteriorly, which becomes obsolete. Septum mucronate, with low rounded mucro.Apertural end with 3–4 well-defined axial ribs. Periostracum thin, translucent brown.
Description. Protoconch unknown.Teleoconchs I and II without obvious separation ( Fig. 118A View FIGURE 118 ), surface smooth ( Fig. 118B View FIGURE 118 ), transition to teleoconch III marked by slight incised axial line ( Fig. 118A View FIGURE 118 ). Teleoconch III sculptured with weakly-developed axial ribs ( Fig. 118C View FIGURE 118 ), transition to teleoconch IV marked by incised axial line, followed by change in sculpture ( Figs. 118A, C View FIGURE 118 ). Teleoconch IV with better developed axial ribs than previous stage ( Fig. 118G View FIGURE 118 ), torqueing of tube may be present ( Fig. 117F View FIGURE 117 ), transition to teleoconch V marked by suture, followed by increase in diameter ( Figs. 118D, F View FIGURE 118 ). Teleoconch V axial ribs present posteriorly and aperturally, obsolete centrally ( Figs. 118H View FIGURE 118 , J–K), transition to teleoconch VI marked by suture, followed by increase in diameter ( Fig. 118J View FIGURE 118 ). Teleoconch VI (last growth stage) average size for genus [Tol 2.52–2.85 mm], larger than previous stage, tubular, mildly and regularly arched [Larc: 0.90–0.99 mm; Arc: 0.19–0.20 mm], subcylindrical, translucent white ( Figs. 117 View FIGURE 117 A–C). Axial sculpture present posteriorly, comprised of rounded, closely arranged ribs, which become obsolete centrally ( Figs. 118 View FIGURE 118 L–M). Axial interspaces shallow, narrower than ribs except those preceding aperture, which become wider ( Figs. 118 View FIGURE 118 L–M). Surface with weak orange peel texture, glossy ( Figs. 117B View FIGURE 117 , 118I View FIGURE 118 ). Posterior [Dpe: 0.44–0.45 mm] with thin edge, rounded to squared shoulder ( Fig. 117E View FIGURE 117 ). Septum mucronate, inflated ( Figs. 117 View FIGURE 117 A–D). Mucro low rounded point, positioned on dorsal margin ( Figs. 117B, E View FIGURE 117 ). Aperture [Da: 0.59–0.61 mm] with 3–5 well-defined axial ribs ( Figs. 118 View FIGURE 118 L–M). No varix. Lip smooth, with slightly deflected peristome ( Fig. 117E View FIGURE 117 ). Periostracum thin, smooth, translucent brown ( Fig. 117A View FIGURE 117 ). Operculum thin, light brown; exterior surface with 7–8 concentric rings ( Figs. 117 View FIGURE 117 G–H). Conceptual reconstruction of growth stages shown in Fig. 119A View FIGURE 119 .
Etymology. The species is named after the type locality.
Distribution and Habitat. Currently only known from the Galapagos Islands. Intertidal, to 20 m. Uncommon on coarse sand and rocky substrates.
Remarks. Late stage subadult Caecum galapagoense can be mistaken for worn C. venustum . However, the larger size, axial ribs, weak orange peel microsculpture, and growth morphology of C. galapagoense easily separate it from C. venustum . Caecum semicinctum is the only other comparable species. Although C. semicinctum has axial ribs both posteriorly and aperturally, they are more pronounced than C. galapagoense . The surface of C. semicinctum is also completely smooth.
| SBMNH |
Santa Barbara Museum of Natural History |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.