Bertia brookei (Adams & Reeve, 1848)
“Gli individui giovani di questa specie sono distintamente perforati ed hanno, alla parte superiore dell' ultimo giro, una carena ottusa di color giallastro. La superficie della conchiglia offre, lungo le suture, massime nei primi giri della spira, certe ammaccature irregolari, rugose, per le quali giustamente si potrebbe dire malleata.” (Issel, 1874)
“The young shell, several of which occurred in the collection sent to the British Museum by Mr. Hose, and which, owing to the kindness of Mr. Edgar Smith, I am enabled to figure, consists of two whorls, is globose, very thin and delicate, transparent, of a ruddy brown colour, with an elongate quadrate aperture flatly convex above, and measures, maj. diam. 18.0, alt, axis 10.5 millim. It would be interesting to know at what age it reaches this size and its full maturity.” (Godwin-Austen, 1891)
“Zwei frische Exemplare aus dem Gebiet des Baramflusses. Sie sind kleiner als der Typus (diam. maj. 66, min. 57, alt. 40 mm), mit schärferer Skulptur, deutlicheren Wellenrunzeln und schärferem Kiel. Die Epidermis zeigt eigentümliche, abwechselnde braune und gelbe Flecken, unter der gelben Kante steht ein deutliches schwarzbraunes Band. Man kann auf diese Unterschiede hin die Form vom Baram wohl als eine eigene Varietät (var. baramensis) abtrennen. Das Thier von Nanina brookei hat nach Godwin-Austen keine Schleimpore, die Art wäre somit überhaupt keine Naninide; Kükenthal hat leider keine Spiritusexemplare mitgebracht. Jedenfalls steht sie besser bei Rhysota, als bei Ariophanta, trotz der Windungsrichtung.” (Kobelt, 1897)
“The character of this animal differs so widely from those in genera with which it is now associated that it does not seem at all in the position it should occupy, and with R. ovum and others will have to be moved. As I have only been able to obtain one example of R. brookei in spirit, it is better to wait until others are examined before doing so.” (Godwin-Austen, 1891)
“The very large size, sinistral coiling, thick shell and rugose upper surface immediately identify this species, which is the largest Bornean land shell. Kobelt’s variety baramensis probably has no taxonomic significance, being based on small individuals.” (Solem, 1964)
Reeve (1854) descriptions on Helix brookei – “Shell sinistral, imperforated, subdiscoid, stout, keeled, above the keel whitish, stained and streaked with chestnut, below it very dark chestnut; whorls four to five, flatly convex, the last rounded and radiately striated at the base, impressed in the middle; aperture obliquely ovate, bluish within; lip thickened, margins joined by a callous layer.”
Tryon (1886) descriptions on Nanina brookei – “Umbilicus nearly covered, solid, obtusely angulated on the periphery, closely striated and minutely granulated, above undulately broadly plicate, shining, chestnut-colored; whorls 5, the last minutely malleated and dark chocolate-colored below the periphery; aperture bluish white, the margins joined by a callus, columella dilated over the umbilicus.”
“Description of the animal from a spirit-specimen: - Foot below not divided as in Macrochlamys, &c.; no mucous gland; the extremity of the foot is flattened, rounded; the pallial margin very narrow and with no pallial groove as seen in the genus Ariophanta, &c. In life I should say the animal was very similar to that of H. ochthoplax, Bs.” (Godwin-Austen, 1891)
“There is not the slightest trace in the spirit-specimen of a mucous gland either above or below, and although von Martens in his work, ‘Die Preuss. Exped, Ost-Asien, Landschneck’ says at p. 188 that in some large coarse species, as Rhysota ovum and Xesta distincta, he found the foot coarsely wrinkled, flat, and with a blunt end, the slime-gland little marked, so that on the whole it resembles the foot of Helix pomatia, yet I feel sure there would remain some indication of the gland in the spirit-specimen; surely the divided sole of the foot would remain visible, and some modification of the pallial margin would show where the slit of the gland was situated, but in this large Bornean species there is no trace left to show that it ever existed.” (Godwin-Austen, 1891)
“The dorsal lobes of the mantle are small for the size of the animal. The left dorsal lobe (we are speaking of a sinistral species) is of the ordinary form; the right is divided into two separate parts, one anterior, the other posterior. Exactly between these two is a right or peristomial shell-lobe and near the respiratory orifice at the inner and upper margin of the aperture a tongue-like left shell-lobe is given off from the margin of the left dorsal lobe. This, although much contracted by the spirit, is evidently of considerable extension when alive. (In Semper's description of Ryssota both shell-lobes are said to be absent.) So that here we have in this sinistral species an approach to Macrochlamys in its shell-lobes, and to the genus Oxytes in its dorsal lobes. The contraction o£ the animal shows the apertures coinciding with the male organ and the spermatheca very plainly. The generative organs are exactly similar to those of Ryssota ovum figured by Semper in 'Reisen im Archipel der Philippinen,' pi. iv. fig. 1, and correspond also with those given on the same plate of R. porphyria, R. semiglobosa, R. dvitija, and R. bulla, simple, and having no amatorial organ. Now, in the five figures given by him of the generative organs of so-called Ariophanta, they all possess the amatorial organ with mucous glands and well-developed sagittae amatorice; thus they are of a much more complicated nature than in the species under review. In R. brookei the male organ consists of a large pear-shaped sac, closing towards the posterior end and contracted for a short distance into a tube, the retractor muscle being at the junction of the vas deferens. The spermatheca is very and unusually long, extending to the albumen-gland; it rises from another pear-shaped muscular sac, on the side of which the oviduct enters. There is nothing remarkable about the ovo-testes or albumen-gland.” (Godwin-Austen, 1891)
“The odontophore - The form of the median teeth very gradually merges into that of the laterals, which become at last little short straight teeth. The central teeth are all unicuspid, the central tooth of all being triangular in form; the formula is (109 . 43 . 1 . 43 . 109) and (152 . 1 . 152.) The lingual ribbon I extracted is nearly perfect, not a row was lost, and it contains 177 rows, giving the enormous number of 54,000 teeth. The jaw has a low central projection, and is not much bent.” (Godwin-Austen, 1891)
Nanina brookei – “Diam. 76, alt. 45 mill.” (Tryon, 1886)
Shell height – 39 mm; Shell width – 67-80 mm.
“Haile’s four adult specimens were 69.5, 71.9, 74.3 and 77.4 mm in diameter, while Museum material was as large as 90 mm.” (Solem, 1964)
Type locality – “Borneo” (Gude, 1917)
Other localites – “Territorio di Sarawak” leg. Doria and Beccari (Issel, 1874); “Koetei” and “Mindai, in Amontai district” (Bock, 1881); “Kusan and Penggiron districts in South-eastern Borneo” leg. W. Doherty (Aldrich, 1889); “Mouth of the Mandai River” leg. Büttikofer/May 1894 and “Foot of Mount Kenepai” leg. Büttikofer (Schepman, 1896); “Kari-Orang” (Martens, 1908); “Sabah; Bukit Kipangi” (Solem, 1964); “Sabah; Dewhurst Bay” (Solem, 1964); “Sabah; Kota Belud” (Solem, 1964)
“Apparently this species is widely distributed in Borneo and is moderately variable in size.” (Solem, 1964)