Everettia corrugata corrugata Laidlaw, 1937
“The species is distinguished from other Bornean Everettia’s by the globose shell, only subimperforata Smith surpassing it in this respect, and especially by the strong corrugations on the shell. These are much more marked than in aglaia Pfr.” (Laidlaw, 1937)
“Remarks: This species is endemic to Mount Kinabalu.” (Liew et al., 2009)
“Diagnostic characteristics: Very strong corrugation near the suture.” (Liew et al., 2009)
Laidlaw (1937) original descriptions on Everettia corrugata – “Shell thin, moderately globose, imperforate, dark brown. Suture impressed, whorls 5. Surface glossy, strongly corrugated immediately below the suture. Spiral striae not visible. Ventral surface smooth. Last whorl increasing rather rapidly; aperture lunate, lip not thickened.’
Liew et al. (2009) descriptions on Everettia corrugata corrugata – “Shell: medium-sized, rather thin, greenish brown, moderately to distinctly elevated, outer whorls slightly shouldered below the suture. Periphery rounded. Above the periphery, shell shiny with very weak and irregular wrinkling that grows stronger towards suture, and forms corrugation just below the suture. Below the periphery, shell without or with scattered, inconspicuous, fine spiral grooves. ...number of whorls up to five;...”
“Body; ochre yellow in colour, with an ill-defined band of gray on each side of the tail, and on the dorsum of the front part of the body, whilst a paler, very ill-defined band of gray runs from the base of the tentacles to the mantle on either side. The mantle is of the same colour as the body, but is densely spotted with jet-black, leapord-like markings. The surface of the visceral sac lying under the outer wall of the shell is similarly coloured, giving the translucent shell a speckled appearance when it contains the animal.” (Laidlaw, 1937)
“Animal: animal head uniform black or grey and this colour extends backward to the end of mantle and downward to the foot-fringe. Some individuals with an ill-defined grey band between tentacles, extended to the end of the tail. Grey smear covering large parts of the animal and extending until the end of the tail. The mantle is covered in sparsely distributed brighter spots. These brighter spots become denser and are agglomerated with the black spots at the last half whorl.” (Liew et al., 2009)
“The genital apparatus is of the type characteristic of the genus. The radula has the central tooth of the same size as the admedian on either side of it. Central and admedians tricuspid, laterals and marginals with minute entocone as in other species. Formula 35-15-1-15-35. The jaw has a definite median projection and is little curved.” (Laidlaw, 1937)
“The visceral mass is 4.25 whorls long, and the lung occupies the distal two-thirds of the last whorls. The stomachal crop is exceptionally long and the stomach occupies more than one whorl from the end of the oesophagus to the top of the stomachal pouch. In relation to the large length of this crop, the intestinal loops are located proximal to the anterior extremity of the crop; they occupy ca. 0.25 whorl. The crop is internally lined with faint longitudinal ridges; two of the duct of the faint groove along the columellar side, anterior to the opening of the duct of the anterior lobe of the digestive gland. A few transversal ridges diverge from this groove. The kidney occupies a little less than one-half of lung length. More than half of its pulmonary surface is covered by the primary ureter, which is ornamented internally with small caruncles.” (Tiller & Bouchet, 1988)
“Central nervous system: The cerebral commissure is very short and the cerebral ganglia are elongated perpendicular to the foot longitudinal axis. The pleural ganglia are located close to the pedal, and the cerebro-pedal and cerebro-pleural connectives are of medium length, the right ones being shorter than the left ones. The ganglia of the visceral chain are displaced toward the left, and all appressed; the right parietal ganglion is larger than the left.” (Tiller & Bouchet, 1988)
“Genital apparatus: the hermaphrodite gland is composed of two lobes. The median portion of the hermaphrodite duct is contorted. The talon is a simple pouch. The glandular portion of the free oviduct, or uterus, is much longer than the non-glandular portion and reaches the atrium, which is very reduced an into which the spermathecal stalk and penis open. The amatorial organ opens into the apical portion of the spermathecal stalk. It is made up of a tube which contains a rod bearing the dart, and glandular acini which open into its apical region via numerous tubules. These acini form a sagittiform mass. The spermathecal head is cylindroid is shape, and attached to the distal region of the prostate by a tract made of conjucntive tissue. The penial complex is a simple tube, without any retractor caecum of flagellum, Its distal half is enclosed in a sheath which is opened apically. The retractor is inserted at its apical third. The portion proximal to the retractor, which may be called the epiphallus, exhibits internal wrinkled longitudinal ridges. Distal to the retractor, the ridges are not wrinkled and coverge at the level of the upper portion of the single pilaster, which reaches the level of the top of the sheath. The distal portion of the penis and atrium exhibit no such ridges, but only the distal part of the pilaster.” (Tiller & Bouchet, 1988)
“Genitalia: maximum length from genital opening to the end of dart-sac (before the visible gland tubules) up to 11.5 mm. The penis, dart-sac, and vagina with thick muscular walls. Penis, vagina arranged near the genital opening then followed by bursa copulatrix and dart-sac where there is little space in the atrium between the openings of penis + vagina and bursa copulatrix + dart-sac. Long bursa copulatrix about two thirds of total dart-sac length.” (Liew et al., 2009)
Everettia corrugata corrugata – “Height up to 11.9 mm; width up to 19.6 mm; diameter of the first three whorls 1.3–1.4, 1.1–1.2, and 1.85–2.3 mm, respectively; height aperture up to 7.4 mm; width aperture up to 10.7 mm.” (Liew et al., 2009)
Type locality – “Pakka, Kinabalu, 10,000 feet” leg. F. N. C. and H. M. P./Apr. 1929 (Laidlaw, 1937)
Other localities – “Sabah; Mount Kinabalu, southern slope, 2578-3333 m (alt.)” (Liew et al., 2009); “Sabah; Mount Kinabalu, southern slope, Paka, 3000 m (alt.)” leg. Vermeulen (Liew et al., 2009); “Sabah; Mount Kinabalu, southern slope, Liwaagu trail” (Liew et al., 2009); “Sabah; Mount Kinabalu, southern slope, Silau-silau” (Liew et al., 2009); “Sabah; Mount Kinabalu, southern slope, Marai-Parai” leg. Vermeulen (Liew et al., 2009)
“Distribution; Sabah: Mount Kinabalu only.” (Liew et al., 2009)
“Upper montane and coniferous primary forest, 2500–3500 m alt.” (Liew et al., 2009)