Revision of the genus-group Hystricella R. T. Lowe, 1855 from Porto Santo (Madeira Archipelago), with descriptions of new recent and fossil taxa (Gastropoda, Helicoidea, Geomitridae)

Abstract

The genus-group Hystricella R. T. Lowe, 1855 is revised on the basis of conchological, anatomical and genetic characteristics. A new genus Wollastoniagen. n., two recent species, W. jessicaesp. n. and W. klausgrohisp. n., and one recent subspecies, W. jessicae monticolassp. n. are described as new to science, as well as five fossil taxa, H. microcarinatasp. n., W. beckmannisp. n., W. falknerorumsp. n., W. ripkenisp. n., and W. inexpectatasp. n. For Helix vermetiformis R. T. Lowe, 1855, H. leacockiana Wollaston, 1878, H. oxytropis R. T. Lowe, 1831, H. duplicata R. T. Lowe, 1831 and H. oxytropis var. ß subcarinulata Wollaston, 1878 lectotypes are designated. For the taxa Helix bicarinata G. B. Sowerby I, 1824, Helix bicarinata var. ß aucta Wollaston, 1878 and Discula bulverii W. Wood, 1828 neotypes are selected. The taxa aucta and subcarinulata are elevated to specific rank. For the hitherto monospecific (sub-) genus Callina R. T. Lowe, 1855 it is shown that it is not closely related to the genus Discula but to the Hystricella-group and its generic rank is confirmed. The taxon D. bulverii W. Wood, 1828 is transferred from the genus Discula s. str. to the genus Callina. A further fossil taxon C. waldenisp. n. is described as new to science.

Keywords: Callina; Discula; Hystricella; Macaronesia; Porto Santo (Madeira Archipelago); Quaternary; Wollastonia gen. n.; phylogeny; recent.

Figure 1.

Map of Porto Santo with offshore islets and map of the Madeiran Archipelago in the Atlantic Ocean.

Figure 2.

Standardisation method for counting the tubercles on the shell surface. AB Maximum diameter CD Maximum height EF height of last whorl HG height of second whorl IC height of third whorl; peristoma angle, measured as the angle between the peristomal plane and the horizontal axis of the shell JK width of the last whorl measured along the maximum diameter (JK/2)² square on the lower surface of the last whorl delimiting the area for the count of tubercles. The centre of the square corresponds to the mid point between J and K and the length of its sides is JK/2. This method allows to compare different specimens and taxa as the area of the square depends on the shell’s overall dimensions and is always proportional (the tubercles that partially traverse the contour of the square were included in the count of tubercles).

Figure 3.

Bayesian 50% majority rule consensus tree based (A) on the concatenated sequences of cox1 and 18S rDNA + ITS1 + 5.8S rDNA + ITS2 + 28S rDNA and (B) on the cox1 sequences alone. Posterior probability values (first value), bootstrap support values from the maximum likelihood analysis with Garli (second value) and iqtree (third value) and maximum parsimony analysis with PAUP* (fourth value) are indicated at the nodes. Only posterior probability values ≥ 0.5 and bootstrap support values ≥ 50% are shown. For phylogenetic relationships of Hystricella, Wollastonia gen. n., Callina, and Discula species included in the analyses, see Figure 4–6.

Figure 4.

Bayesian 50% majority rule consensus tree based on cox1 sequences of Hystricella species. Posterior probability values (first value), bootstrap support values from the maximum likelihood analysis with iqtree (second value) and Garli (third value) and maximum parsimony analysis with PAUP* (fourth value) are indicated at the nodes. Only posterior probability values ≥ 0.5 and bootstrap support values ≥ 50% are shown. The inset map shows the distribution of H. bicarinata (blue), H. echinulata (green) and putative hybrids of both species (red) on Porto Santo. The tip labels on the tree are coloured accordingly. For information on vouchers, see Table 1 and the corresponding material lists under the species’ sections. The inset tree shows the position of Hystricella in relation to the other investigated genus-group taxa based on the analysis of concatenated mitochondrial and nuclear sequences as shown in Figure 3.

Figure 5.

Bayesian 50% majority rule consensus tree based on cox1 sequences of Wollastonia gen. n. species. Posterior probability values (first value), bootstrap support values from the maximum likelihood analysis with Garli (second value) and iqtree (third value) and maximum parsimony analysis with PAUP* (fourth value) are indicated at the nodes. Only posterior probability values ≥ 0.5 and bootstrap support values ≥ 50% are shown. For information on vouchers, see Table 1 and the corresponding material lists under the species’ sections. The inset tree shows the position of Wollastonia gen. n. in relation to the other investigated genus-group taxa based on the analysis of concatenated mitochondrial and nuclear sequences as shown in Figure 3.

Figure 6.

Bayesian 50% majority rule consensus tree based on cox1 sequences of (A) Callina and (B) Discula species. Posterior probability values (first value), bootstrap support values from the maximum likelihood analysis with Garli (second value) and iqtree (third value) and maximum parsimony analysis with PAUP* (fourth value) are indicated at the nodes. Only posterior probability values ≥ 0.5 and bootstrap support values ≥ 50% are shown. For information on vouchers, see Table 1 and the corresponding material lists under the species’ sections. The inset tree shows the position of Callina and Discula in relation to the other investigated genus-group taxa based on the analysis of concatenated mitochondrial and nuclear sequences as shown in Figure 3.

Figure 7.

Distribution of the genus Hystricella. Filled circles refer to recent and open circles to fossil records.

Figure 8.

Radulae and jaws of Hystricella species. A Hystricella bicarinata, Ribeira da Areia B Hystricella echinulata, path to Pico Branco.

Figures 9–19.

Shells of Portosanctan and Madeiran Geomitridae. 9 Hystricella bicarinata, Pico do Castelo, S slope around the Miradouro 10 Discula discina, Porto da Morena 11 Discula (Mandahlia) tectiformis, Pico do Baixo 12 Callina rotula, Cabeco dos Bades 13 Actinella (Plebecula) littorinella, E of Pico do Castelo 14 Caseolus (C.) innominatus portosanctanus, Ribeira da Areia 15 Caseolus (Helicomela) punctulatus punctulatus, Fonte da Areia 16 Caseolus (Leptostictea) leptosticus, Ponta do Garajau, Madeira 17 Serratorotula juliformis, Pico de Ana Ferreira 18 Spirorbula depauperata, Pico de Ana Ferreira 19 Lemniscia michaudi, Terra Chã. Scale bar: 1 cm.

Figures 20–30.

Outer distal genitalia of Portosanctan and Madeiran Geomitridae. 20 Hystricella bicarinata, Capela da Graça 21 Discula polymorpha alleniana, Porto Moniz, Madeira 22 Discula (Mandahlia) tectiformis, Pico do Baixo 23 Callina rotula, Cabeco dos Bades 24 Serratorotula juliformis, Pico de Ana Ferreira 25 Lemniscia michaudi, Terra Chã 26 Actinella (Plebecula) littorinella E of Pico do Castelo 27 Caseolus (C.) innominatus portosanctanus, Ribeira da Areia 28 Caseolus (Helicomela) punctulatus punctulatus, Fonte da Areia 29 Caseolus (Leptostictea) leptosticus, Ponta do Garajau, Madeira 30 Spirorbula depauperata, Pico de Ana Ferreira. Scale bars 1 mm.

Figures 31–32.

31 Original figure of Helix bicarinata G. B. Sowerby I, 1824 from Sowerby (1824: pl. 3 fig. 7) 32 Original figure of Helix duplicata R. T. Lowe, 1831 from R. T. Lowe (1831: pl. 6 fig. 20).

Figures 33–37.

Shells of Hystricella bicarinata. 33 neotype of Hystricella bicarinata, Pico do Castelo, S slope around the Miradouro, SMF 348936 34 syntype of H. duplicata R. T. Lowe 1831, NHM 1948.7.8.34; Shells of Hystricella bicarinata 35 Capela da Graça 36 Pico do Castelo, S slope around the Miradouro 37 Pico da Gandaia. Scale bar 1 mm.

Figures 38–45.

Genitalia and anatomy of Hystricella bicarinata. Pico do Castelo, S slope around the Miradouro: 38 whole genitalia excluding part of OSD, AG and gonads 39 ornamentation of the inner walls of the distal penis, the vagina and the genital atrium 40 transverse section of penial papilla. Pico da Gandaia: 41 whole genitalia excluding gonads 42 ornamentation of the inner walls of the flagellum, the penial complex, the vagina and the genital atrium. Ribeira de Serra de Dentro: 43 jaw. Pico da Gandaia: 44 mantle border. Ribeira de Serra de Dentro: 45 whole genitalia excluding part of OSD, AG and gonads. Scale bars 1 mm.

Figures 46–53.

Genitalia and anatomy of Hystricella bicarinata. Capela de Graça: 46 whole genitalia excluding part of OSD, AG and gonads 47 penial papilla 48 longitudinal section of the penial papilla 49 ornamentation of the inner walls of the flagellum, the penial complex, the vagina and the genital atrium. Ridge between Pico do Facho and Pico da Gandaia: 50 whole genitalia excluding part of OSD, AG and gonads. NE slopes of Pico do Castelo: 51 section of vagina. Capela da Graça: 52 jaw. S slopes Pico do Facho: 53 mantle border. Scale bars 1 mm.

Figure 54.

Distribution of Hystricella bicarinata.

Figures 55–70.

Shells, anatomy and genitalia of the putative hybrid populations of H. bicarinata and H. echinulata. Shells: 55 Pedregal de Dentro 56 Ribeira Formosa 57 Pico de Cabrita 58–59 Cabecos dos Bades 60 Pedregal de Fora. Genitalia and anatomy. Cabecos dos Bades: 61 whole genitalia excluding part of OSD, AG and gonads 62 section of penial papilla 63 penial papilla 64 inner walls of atrium and penis 65 mantle border. Pedregal de Dentro: 66 whole genitalia excluding part of OSD, AG and gonads 67 inner walls of atrium and penis 68 jaw 69 section of penial papilla 70 vaginal glands and vaginal appendage. Scale bars 1 mm.

Figures 71–74.

Shells of Hystricella aucta. 71 neotype, SMF 348937 from Barbinha 72 Barbinha 73 Ponta da Canaveira 74 Hystricella microcarinata sp. n., holotype, SMF 348924. Scale bar: 1 mm.

Figure 75.

Distribution of Hystricella aucta.

Figure 76.

Distribution of Hystricella microcarinata sp. n.

Figures 77–78.

77 original figure of Helix echinulata R. T. Lowe, 1831 from R. T. Lowe (1831: pl. 6 fig. 19) and 78 lectotype of Helix echinulata R. T. Lowe, 1831, NMH 1968.586 ex coll. R. T. Lowe. Scale bar: 1 mm.

Figures 79–82.

Shells of Hystricella echinulata. 79–80 Terra Chã 81 S slope of Pico Banco 82 steep path from Pico Branco to Terra Chã. Scale bar 1 mm.

Figures 83–93.

Anatomy and genitalia of Hystricella echinulata. Terra Chã: 83 whole genitalia excluding gonads 84 ornamentation of the inner walls of the distal penis, the distal vagina and the genital atrium 85 ornamentation of the inner walls of the flagellum, the penial complex, the vagina and the genital atrium 86 penial papilla 87 whole genitalia excluding part of OSD, AG and gonads 89 penial papilla and ornamentation of the inner walls of the flagellum 91 mantle border 92 section of penial papilla. Faja Pequena: 88 section of vagina 90 jaw 93 whole genitalia excluding gonads. Scale bars 1 mm.

Figure 94.

Distribution of Hystricella echinulata.

Figure 95.

Lectotype of Hystricella echinoderma, NHM 1875.02.02-52. Scale bar 1 mm.

Figure 96.

Distribution of Hystricella echinoderma.

Figure 97.

Distribution of the genus Wollastonia gen. n. Filled circles refer to recent and open circles to fossil records.

Figure 98.

Jaws and radulae Wollastonia gen. n. A W. leacockiana Pico de Ana Ferreira B W. oxytropis Pico do Concelho C W. jessicae jessicae sp. n. Vale do Touro.

Figures 99–102.

99 Wollastonia turricula original figure as in R. T. Lowe, 1831 (from Lowe 1831: pl. 6 fig. 21). Shell of Wollastonia turricula 100 shell of the lectotype from loc. typ., ex coll. R. T. Lowe NMH 1948.7.8.35 101, 102 shells from Ilhéu de Cima. Scale bar 1 mm.

Figures 103–111.

Anatomy and genitalia of Wollastonia turricula, Ilheu de Cima. 103 whole genitalia excluding gonads 104 mantle border 105 section of vagina 106 whole genitalia excluding part of OSD, AG and gonads 107 ornamentation of the inner walls of the flagellum 108 ornamentation of the inner walls of the flagellum, the penial complex, the vagina and the genital atrium 109 longitudinal section of penial papilla 110 section of penial papilla 111 tip of penial papilla. Scale bars 1 mm.

Figures 112–116.

112–114 shells of Helix turricula var. pererosa RAM EXEMS-1720-1909-d39-74 115 Ilheu de Cima 116a, 116b labels from RAM. Scale bar 1 mm.

Figure 117.

Distribution of Wollastonia turricula. Filled circles refer to recent and open circles to fossil records.

Figures 118–120.

Shells of Wollastonia vermetiformis. 118 lectotype of Helix vermetiformis R. T. Lowe, 1855, NMH 1968.588 ex coll. Lowe 119 recent specimen from Pico do Baixo 120 subfossil specimen from Porto dos Frades. Scale bar 1 mm.

Figure 121.

Distribution of Wollastonia vermetiformis. Filled circles refer to recent and open circles to fossil records.

Figures 122–124.

Shells of Wollastonia ripkeni sp. n. 122 holotype, SMF 348929 123, 124 paratypes from the loc. typ. Scale bar 1 mm.

Figure 125.

Distribution of Wollastonia ripkeni sp. n.

Figures 126–128.

Shells of Wollastonia falknerorum sp. n. 126 holotype, SMF 348925127 127, 128 paratypes from the loc. typ. Scale bar 1 mm.

Figure 129.

Distribution of Wollastonia falknerorum sp. n.

Figures 130–132.

Shells of Wollastonia leacockiana. 130 lectotype of Helix leacockiana Wollaston, 1878, NMH 1875.12.31.137d, ex coll. Wollaston 131 Pico de Ana Ferreira 132 Ilheu de Ferro. Scale bar 1 mm.

Figures 133–141.

Genitalia and anatomy of Wollastonia leacockiana. Pico de Ana Ferreira, N slopes: 133 section of penial papilla 134 section of vagina 135 whole genitalia excluding gonads 136 tip of the penial papilla 137 longitudinal section of penial papilla 138 ornamentation of the inner walls of the distal penis, the distal vagina and the genital atrium 139 whole genitalia excluding gonads 140 jaw 141 mantle border. Scale bars 1 mm.

Figure 142.

Distribution of Wollastonia leacockiana.

Figures 143–145.

Shells of Wollastonia beckmanni sp. n. 143 holotype, SMF 348927 144 paratype from the loc. typ. 145 Vale do Touro. Scale bar 1 mm.

Figure 146.

Distribution of Wollastonia beckmanni sp. n.

Figures 147–149.

Shells of Wollastonia jessicae jessicae sp. n. 147 holotype, NMWC Z.2016.013.00001 148 paratype from the loc. typ. 149 subfossil specimen from Vale do Touro. Scale bars 1 mm.

Figures 150–157.

Genitalia and anatomy of Wollastonia jessicae jessicae sp. n. S slope of hill E of Ribeira Santo Antonio and W of Vale do Touro: 150 whole genitalia excluding gonads 151 section of proximal penis at the intersection with vas deferens 152 whole genitalia excluding gonads 153 ornamentation of the inner walls of the distal penis, the distal vagina and the genital atrium 154 jaw 155 mantle border 156 whole genitalia excluding part of OSD, AG and gonads 157 ornamentation of the inner walls of the distal penis, the distal vagina and the genital atrium. Scale bars 1 mm.

Figure 158.

Distribution of Wollastonia jessicae jessicae sp. n. Filled circles refer to recent and open circles to fossil records.

Figures 159–161.

Shells of Wollastonia jessicae monticola ssp. n 159 holotype, NMWC Z.2016.013.00010 160, 161 paratypes from the loc. typ. Scale bar 1 mm.

Figures 162–166.

Genitalia and anatomy of Wollastonia jessicae monticola ssp. n. Zimbreiro, 200 m SW of the village: 162, 163 whole genitalia excluding gonads 164 ornamentation of the inner walls of the distal penis, the distal vagina and the genital atrium 165 penial papilla and inner ornamentation of proximal penis 166 mantle border. Scale bars 1 mm.

Figure 167.

Distribution of Wollastonia jessicae monticola ssp. n.

Figures 168–170.

Shells of Wollastonia klausgrohi sp. n. 168 holotype, NMWC Z.2016.013.00003 169, 170 paratypes from the loc. typ. Scale bar 1 mm.

Figures 171–181.

Genitalia and anatomy of Wollastonia klausgrohi sp. n. Casa Velhas, next to the W edge of the old quarry: 171 section of penial papilla 172 ornamentation of the inner walls of the flagellum, the penial complex, the vagina and the genital atrium 173 penial papilla 174, 175 whole genitalia excluding part of OSD, AG and gonads 176 ornamentation of the inner walls of the flagellum, the penial complex, the vagina and the genital atrium 177 section of vagina 178 jaw 179 mantle border 180 penial papilla 181 whole genitalia excluding gonads. Scale bars: 1 mm.

Figure 182.

Distribution of Wollastonia klausgrohi sp. n.

Figures 183–187.

Shells of Wollastonia oxytropis. 183 original figure of Helix oxytropis R. T. Lowe, 1831 from Lowe (1831: pl. 6 fig. 18) 184 lectotype of Helix oxytropis R. T. Lowe, 1831, NMH 1968.546 ex coll. Lowe 185 paralectotype 186, 187 recent specimens from Pico do Concelho. Scale bar 1 mm.

Figures 188–194.

Genitalia and anatomy of Wollastonia oxytropis from Pico do Concelho: 188 whole genitalia excluding part of OSD, AG and gonads. Pico do Concelho: 189 section of vagina 190 tip of penial papilla 191 whole genitalia excluding part of OSD, AG and gonads 192 mantle border 193 ornamentation of the inner walls of the flagellum, the penial complex, the vagina and the genital atrium 194 jaw. Scale bars 1 mm.

Figure 195.

Distribution of Wollastonia oxytropis. Filled circles refer to recent and open circles to fossil records.

Figures 196–198.

Shells of Wollastonia subcarinulata. 196 lectotype, NMWC 80.202, Acc 55.158; 197–198 specimens from Barbinha, Quaternary aeolinites. Scale bar 1 mm.

Figure 199.

Map of the distribution of Wollastonia subcarinulata.

Figures 200–202.

Shells of Wollastonia inexpectata sp. n. 200 holotype, SMF 348930 201 paratype NMWC 80.202 Acc. 55 158 202 label of the lot NMWC 80.202 Acc. 55 158. Scale bar 1 mm.

Figure 203.

Distribution of Wollastonia inexpectata sp. n.

Figure 204.

Distribution of the genus Callina. Filled circles refer to recent and open circles to fossil records.

Figures 205–209.

205, 206 radula and jaw of Callina rotula from Ribeira da Areia 207 radula and jaw of Callina bulverii 208 original figure of Helix rotula R. T. Lowe, 1831 (from Lowe 1831: pl. 6 fig. 10) 209 lectotype of Callina rotula, ANSP 97116. Scale bar 1 mm.

Figures 210–213.

Genitalia and anatomy of Callina rotula. Ribeira da Areia: 210 whole genitalia excluding part of OSD, AG and gonads 211 ornamentation of the inner walls of the flagellum, the penial complex and the genital atrium 212 penial papilla 213 cross section of penial papilla. Scale bars 1 mm.

Figure 214.

Distribution of Callina rotula. Filled circles refer to recent and open circles to fossil records.

Figures 215–216.

Shells of Callina waldeni sp. n. 215 holotype, MMF 46276 216 paratype from E of Vila Baleira, S slope of the hill above Vale do Touro. Scale bar 1 mm.

Figure 217.

Distribution of Callina waldeni sp. n.

Figures 218–219.

Shells of Callina bulverii. 218 neotype, SMF 348938 219 specimen from Zimbreiro. Scale bar 1 mm.

Figures 220–226.

Genitalia and anatomy of Callina bulverii. S slope of Pico do Facho: 220 whole genitalia excluding part of OSD, AG and gonads 221 ornamentation of the inner walls of the vagina, the penis and the genital atrium 222 cross section of the duct of the bursa copulatrix 223 penial papilla 224 inner walls of epiphallus 225 cross section of penial papilla 226 longitudinal section of penial papilla. Scale bars 1 mm.

Figure 227.

Distribution of Callina bulverii.

Figures 228–232.

Comparison of the inner genitalia of Discula (Discula) and Discula (Mandahlia) species. 228–230 Discula (Mandahlia) tectiformis from summit slopes of Pico do Baixo: 228 cross sections of the penial complex 229 inner walls of penis, atrium and distal vagina 230 inner walls of epiphallus 231–232 Discula (Discula) polymorpha polymorpha from Porto Moniz, Madeira: 231 inner walls of epiphallus, penis, and atrium 232 cross section of penial papilla.