Callina rotula (R. T. Lowe, 1831)

Mattia, Willy De, Neiber, Marco T. & Groh, Klaus, 2018, 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), ZooKeys 732, pp. 1-125 : 66-71

Callina rotula (R. T. Lowe, 1831) Figs 206-209, 210-213, 214

List of synonyms.

1831 Helix rotula R. T. Lowe: 53, pl. 6 fig. 10.

1847 Helix rotula - L. Pfeiffer in L. Pfeiffer 1847-1848: 216.

1854 Helix rotula - Reeve in Reeve 1851-1854: pl. 137 fig. 854.

1854 Helix rotula - Albers: 28, pl. 6 figs 16-18.

1855 Helix (Callina) rotula - R. T. Lowe: 183.

1867 Helix (Tectula) rotula - Paiva: 82.

1867 Helix (Tectula) rotula var. α major Paiva: 83.

1867 Helix (Tectula) rotula var. β minor Paiva: 83.

1867 Helix (Tectula) rotula var. γ cerina Paiva: 83.

1867 Helix (Tectula) rotula var. δ monstrosa Paiva: 83.

1878 Helix (Callina) rotula - Wollaston: 151-152.

1888 Helix rotula - Tryon in Tryon [and Pilsbry] 1888: 46, pl. 9 fig. 4.

1894 Geomitra rotula - Pilsbry in Pilsbry 1893-1895: 241.

1922 Ochthephila (Callina) rotula mut. grisea T. D. A. Cockerell: 44-46 [unavailable, infrasubspecific].

1931 Geomitra (Actinella) rotula - Nobre: 81, figs. 30 + 31.

1950 Discula (Callina) rotula - Mandahl-Barth: 36.

1983 Discula (Callina) rotula - Waldén: 267, note p. 273 [partim].

2002 Discula (Callina) rotula - Bank et al.: 124.

2005 Callina rotula - Schileyko: 218-219.

2008 Discula (Callina) rotula - Seddon: 78, pl. 28 fig. E, map 175.

2011 Discula rotula - Seddon: e.T156384A4936221.

Type material.

ANSP 97116, lectotype (herewith designated), from loc. typ., ex coll. R. T. Lowe-T. V. Wollaston. For the original figure of Helix rotula R. T. Lowe, 1831 (from Lowe 1831: pl. 6 fig. 10), see Fig. 206. The lectotype of Helix rotula R. T. Lowe, 1831, W = 11.2 mm, is depicted in Fig. 207.

Further material examined.

All from Porto Santo. Fossil: CKG/1 juv., SE slope of the Pico de Ana Ferreira, 33°02'36"N / 16°22'11"W, 220 m, leg. K. & C. Groh & J. & C. Hemmen, Jul. 6 1983; CKG/15, Barbinha, Quaternary aeolinites, 33°04'04"N / 16°17'49"W, 8 m, leg. K. & C. Groh & J. & C. Hemmen, Jul. 4 1983; CFW 11227/1, Ponta da Galé, E end of the tunnel, 33°03'44"N / 16°17'45"W, 30 m, leg. F. Walther & E. M. Gryl, Apr. 1 2017. Recent: CKG/20, NW slope of Pico Juliana, along the upper Ribeira do Pedregal, 33°05'32"N / 16°19'25"W, 340 m, leg. K. & C. Groh & J. & C. Hemmen, Jul. 3 1983; CKG/1, Terra Chã, path to forestry house, 33°05'37"N / 16°18'03"W, 350 m, leg. K. Groh & J. Hemmen, Jul. 8 1983; CKG/2, region NW of the summit of Pico do Concelho, 33°04'43"N / 16°18'01"W, 200-230 m, leg. K. Groh & J. Hemmen, Jun. 29 1983; CKG/1, SW slope of Lombo Branco, 33°05'46"N / 16°18'46"W to 33°05'38"N / 16°18'13"W, 150-400 m, leg. K. Groh & J. Hemmen, Jul. 8 1983; CKG/5, CMN/5, W slope and crest of the hill W of Pico do Concelho (Pico Novalido?), 33°04'50"N / 16°19'37"W, 100-250 m, leg. K. Groh & J. Hemmen, Jun. 29 1983; CKG/10, N slope of Pico do Facho, 33°05'04"N / 16°19'25"W, approx. 450 m, Tamarix - and Pinus -forest, leg. K. Groh & J. Hemmen, Jun. 28 1983; CMN/1, Pico de Juliana towards Cabo de Grafa, 33°05'34"N / 16°19'11"W, 300 m, leg. K. & C. Groh, Aug. 13 1985; CWDM/5, Ribeira da Areia, serpentine 240 m NNW the quarry, under stones, 33°04'51"N / 16°18'41"W, 120 m, leg. W. De Mattia & J. Macor, May 15 2014; CWDM/4, beginning of path to Pico Branco, 33°05'48"N / 16°18'54"W, 180 m, leg. W. De Mattia & J. Macor, May 15 2015; CWDM/5, Pico de Cabrita, Pedregal de Dentro, northern slope close to the road, under stones, 33°05'42"N / 16°19'23"W, 240 m, leg. W. De Mattia & J. Macor, May 15 2015; CWDM/5, path to Pico Branco, terraced S slope of Pico Branco, under stones, 33°05'35"N / 16°18'25"W, 270 m, leg. W. De Mattia & J. Macor, May 16, 2015; CWDM/4, Cabeco dos Bades at the confluence of the two streams, under stones, 33°06'09"N / 16°19'25"W, 30 m, leg. W. De Mattia & J. Macor, May 19 2015; CWDM/4, lake S of Ribeira da Serra de Dentro, under stones, 33°04'48"N / 16°18'31"W, 70 m, leg. W. De Mattia & J. Macor, May 22 2014; CWDM/5, path to Pico Branco, eastern steep part of path to Pico Branco, under stones, 33°05'29"N / 16°18'14"W, 320 m, leg. W. De Mattia & J. Macor, May 22 2014; CWDM/4, Terra Chã-Pico Branco ridge, under stones, 33°05'38"N / 16°18'01"W, 335 m, leg. W. De Mattia & J. Macor, May 16 2014; ZMH 120617/2, Pico de Cabrita, 33°05'02"N / 16°19'16"W, 460 m, ex coll. W. Fauer, leg. M. Vilella, Mar. 20 1964; ZMH 120616/3, Pico de Juliana, 33°05'32"N / 16°19'18"W, c. 360 m, ex coll. W. Fauer, leg. J. & C. Hemmen, Jun. 29 1983; ZMH 110140/15, slopes of Pico do Facho, under stones, c. 33°04'59"N / 16°19'25"W, 430 m, leg. E. Clauss, Sep. 22 1992; CFW 10997/11, ZMH 92904/4, southwestern slope of Pico Branco ca. 250 m SW of the top, 33°05'29"N / 16°18'13"W, 310 m, leg. F. Walther & E. M. Gryl, Mar. 31 2017; CFW 11107/2, S slope of Pico do Castelo, near parking area, 33°04'42"N / 16°20'06"W, 260 m, leg. F. Walther & E. M. Gryl, Apr. 1 2017; CFW 10889/4, ZMH 92889/1, Ribeiro do Pedregal, upper part, downstream of the abandoned houses, 33°05'59"N / 16°19'32"W, 120 m, leg. F. Walther, Apr. 2 2017; CFW 10878/4, Pico do Facho, northwestern slope, 33°05'13"N / 16°19'38"W, 370 m, leg. F. Walther & E. M. Gryl, Apr. 3 2017; CFW 10835/4, ZMH 92811/1, Casinhas, N of Capela da Graça, 33°04'27"N / 16°19'27"W, 150 m, leg. F. Walther, Apr. 4 2017; ZMH 24259/2, Madeira Archipelago, without locality data, ex coll. Altonaer Museum; ZMH 24260/1, Porto Santo, without exact locality data, ex coll. Altonaer Museum, ex coll. O. Semper, ex coll. Dohrn.

Loci typici.

[rotula] Hab. in montibus Portus Sti.; not given for the var. α to δ of Paiva. [grisea] Porto Santo, main island.

Original descriptions.

[rotula] from Lowe, 1831: H. testa rotundata, conoideo-depressa, supra sub-planulata, subperforata, carinata, scabra, nitidiuscula, fasciata: spira conoidea, obtusissima; sutura obsoleta; anfractibus planis, transverse striatis et granulatis; ultimo acute carinato, carina ad peristoma obsoleta: aperture lunata, extrorsum dilatata; peristomate intiis incrassato, acuto, sub-expanso; ad angulum internum reflexo, calloso, perforationem obtegente. Axis 3 lin. Diam. 6. Anfr. 8; from Paiva 1867: [var. α major] testa distincto fasciata, ampliore; [var. β minor] testa duplo minore, fasciis angustioribus; [var. γ cerina] testa albida, omnio efasciata; [var. δ monstrosa] testa fasciata, anfractibus subsolutis, carina supra suturam valde prominent, rarissima; [grisea]; from Cockerell 1922: Shell pale gray, flecked with creamy white.

Redescription of shell.

The shell is dextral, solid, hairless, and it is usually discoidal to tectiform. The protoconch is dark brown with 1.5 to 1.7 whorls. It is almost smooth along the first whorl and shows radial striae along its remaining portion. The teleoconch has from 5.3 to 5.7 rapidly increasing whorls. It is more or less horn brown in colour on the upper side, mottled with small light brown scattered areas. One more or less blurred chestnut band is sometimes visible along the last three whorls. On the underside of the last whorl two brown bands are present that are usually not very broad. The peri-umbilical area is usually the lightest in colour. The spire has a rather conical shape, with the rather flat whorls being separated by a shallow suture. The last whorl is not equipped with a real keel but is rather distinctly angled. The peripheral angulation is often lighter in colour compared to the remaining shell surface, usually whitish to light brown. The surface of the shell has very fine but clearly visible, rather regularly spaced, growth lines. Small tubercles are present on surface of the teleoconch. These tubercles are concentrated along the growth lines, and especially on the underside quite dense. The last whorl is only slightly wider than the penultimate whorl and slightly descending towards the aperture. The umbilicus is completely closed. The aperture is elliptical and the peristome is white and rather solid. A strong callous along the lower palatal side is present, just behind the aperture. The peristome is interrupted along the palatal area and partially reflected along its basal side. The palatal area does not show any callouses or thickenings. See Figs 208-209.

Measurements.

D 11.1 ± 0.6 mm (range 10.4-11.8 mm); H 7.2 ± 0.7 mm (range 6.3-8.1 mm); FW 5.1 ± 0.2 mm (range 5.0-5.6 mm); PA 44.0 ± 2.1° (range 42.3-46.4°); NT> 100; NW 7.4 ± 0.3 (range 7.0-7.6) (n = 25). Ratio D/H 1.6; ratio FW/H 0.6.

Body.

As in the genus description.

Genital anatomy.

A convoluted hermaphroditic duct arises from the gonad. The albumen gland is long and thin and is connected to an approximately twice as long sperm-oviduct that consists of a prostatic and a uterine portion. The prostatic part extends into a thin vas deferens which is approximately twice as long as the sperm-oviduct and which inserts into the penial complex. The distal portion of the uterine part ex tends into the free oviduct, turning into a vagina at the level of the duct of the bursa copulatrix. The free oviduct is approximately as long as the vagina. The duct of the bursa copulatrix is very wide, approximately as long as the penial complex and usually uniform in diameter. It ends in an oval bursa copulatrix. The transition area between the duct and the bursa itself is not sharply delimited but rather gradually widens. The spermatophore is unknown. One tuft of digitiform glands arises from the proximal part of the vagina. There are usually two, equally long and very rarely branched glands present. A vaginal appendix arises from the vagina’s wall, just distal of the glandular tuft. Very smooth, rather widely separated, and little elevated, irregularly spaced pleats run longitudinally along the inner surface of the vagina, reaching the genital atrium but not as far as the genital orifice. The atrium is short and wide. Its internal walls are smooth. The penial complex consists of a flagellum, an epiphallus (which extends from insertion of vas deferens to penial retractor muscle) and a penis that inserts into the genital atrium. The penial flagellum is short, cylindrical and with a pointed apex. It is usually ¼ as long as the epiphallus. Its internal walls are completely smooth. The epiphallus is usually ⅓ longer than the penis. Its internal walls are equipped with 20-25 very fine, and elevated longitudinal pleats. The retractor muscle is strong and approximately half as long as the epiphallus. The penis lacks any muscular or glandular sheath. It is extremely thick-walled and approximately ⅔ as long as the epiphallus. It is cylindrical and slightly swollen in its distal part. The inner walls of the penis are smooth. The section where the large penial papilla is located is usually detectable from the outside by virtue of a circular swelling corresponding to the origin of the papilla itself. The penial papilla reaches half the length of the penis. It is conical to subcylindrical in shape and has smooth external walls. Its opening emerges apically. The channel of the penial papilla is thin and narrow. The inner lumen of the penial papilla is occupied by a spongy and sturdy tissue which directly connects with the walls of the epiphallus. The longitudinal section of the penial papilla shows that its walls are the continuation of the penial walls that abruptly bend inwards (See Schileyko (2005) and Figs 210-213).

Ecology.

Callina rotula is commonly found under volcanic rocks scattered on grassland in open fields that are more or less sloping. The specimens aestivate among the soil and are only rarely attached to the lower surface of the rocks.

Distribution.

Callina rotula is endemic to the island of Porto Santo (Madeiran Archipelago, Portugal). It is commonly found in the central-northern areas, north of the line Farrobo-Calhau da Serra de Fora. It is not present on the small islets surrounding the eastern side of the main island, namely Ilhéu de Cima and Ilhéu de Cenouras. See the distributional map in Fig. 214.

Taxonomic remarks.

Waldén (1983: 273) referred to a fossil specimen resembling C. rotula under his remark 72 from the MMF collection. After checking Waldén's specimen in the collection of the MMF and a recently collected shell, this fossil form apparently belongs to a new species that is described below.

Status and conservation.

According to Seddon (2011f) the species is considered Least Concern (LC).