Pesticide with a difference

 

This is just what you need to kill sinister sinistrals and restore your snail population to one made up of normal, dextral pests.

Phillumenic conundrum

Prior to this event I had never heard of the obscure hobby of phillumeny, but what should have been a casual glance inside an antiques shop in Santa Cruz necessitated some brushing up on the matter. I could not resist leaving this singular item to gather dust on a shelf unless that shelf was mine.

this is all I know about this set

A defunct (?) match factory in Las Palmas (capital city of Gran Canaria), Fosforera Canariense, produced this nice set of 24 matchboxes sometime last century after its foundation in 1935. Information regarding such items is hard to come by, on-and-offline, therefore not much more is known at this stage.

click on image for large version

The set is called Caracolas Marinas (marine snails) and features 24 species of molluscs (inexplicably consisting of one bivalve and 23 predominantly tropical, not-all-marine, gastropods) heavily inked onto a pale blue background. The way they are packaged makes it impossible to see what is on the hidden side of each matchbox, and where, presumably, the species identifications are printed.

click on image for large version

Now, I am sorely tempted to tear open the polythene covering holding the set together in order to read them; on the other hand, doing so will detract from the neatness and value of the boxed set. I'm a stickler for 'accurate' identification (as opposed to mere Cypraea, Murex, Lambis, Harpa, Conus, Architectonica, Mitra, Cymatium etc.) but these cardboard versions will have to remain a mystery, at least until curiosity gets the upper hand.

Los Gigantes cliffs in Tenerife

The highest cliffs in the volcanic island of Tenerife, in the Atlantic Ocean, are found on its western side. These majestic geological features are known as 'Los Gigantes' (the Giants), a term which perfectly befits their massive presence.

Acantilados de Los Gigantes, Tenerife

The cliffs are (like much of the island) composed of 'alkali' basalt, a volcanic rock which contains high proportions minerals like feldspar, olivine and iron oxides. These mineral accretions are sometimes large enough to be seen with the naked eye:

feldspar (white crystals) and iron oxides (brown aggregate) in basalt

feldspar (white crystals) and iron oxides (brown aggregate) in basalt

olivine (greenish crystals) in basalt

The basalt is found in layers which are texturally highly varied, each layer indicating a different episode or process in the island's violent volcanic history. For example, the breccia-like ignimbrite forms when a stream of lava partly melts the substrate upon which it is flowing and drags the pieces of hot rock along, subsequently welding the fragments together into a pudding-like composition, in this case containing fragments of widely disparate size:

ignimbrite

Another rock which stands out visually is red ochre, which forms when hot lava passes over well-developed soils. It can be seen as a thin reddish line in the following photograph:

red ochre stratum

Over millions of years, boulders of basalt tumble down the cliffs and are rounded by wave and wind action.

boulders on the shore

As a rough habitat largely characterized by strong currents and abrasive basalt gravel, the interface between the sea and land is largely devoid of macrofauna, though some usual suspects make an appearance. Most notable of these are two Macaronesian endemics - the limpet Patella piperata Gould, 1846 and the periwinkle Littorina striata King & Broderip, 1832. Closer to mean sea level, Patella tenuis crenata d'Orbigny, 1840 makes an appearance. The third species of limpet that may be encountered on Tenerife is Patella ulyssiponensis Gmelin, 1791, though none of these were seen during this trip. 

Littorina striata King & Broderip, 1832

Littorina striata King & Broderip, 1832

Patella piperata Gould, 1846

Patella piperata Gould, 1846

Specimens of Osilinus sauciatus (Koch, 1845) were found in small clusters, mostly using deep cracks as shelter.

Osilinus sauciatus (Koch, 1845)

Species spotlight XI

Mercuria cf. similis (Draparnaud, 1805)
Xlendi, Gozo

The family Hydrobiidae is a large group of small snails with gills (not lungs) living in aquatic habitats, predominantly fresh and brackish. Four representatives are found in the Maltese Islands, the largest of which is the freshwater Mercuria cf. similis (Draparnaud, 1805)*. As a denizen of fresh water bodies, usually close to Blue Clay substrates, Mercuria is rare in Malta but rather more frequent in Gozo. Colonies graze microscopic algae growing on submerged or perennially wet overhangs, and seem to prefer running, clear water. The blue-greyish shell, large shell size and habitat distinguishes it from a similar species, Pseudamnicola moussonii (Calcara, 1841), which will be discussed in a future post.

*In taxonomy, a 'cf.' indicates uncertainty in assigning a specific epithet to a specimen. The uncertainty in this case derives from anatomical differences between Maltese Mercuria and other populations of M. similis.

Mġarr, Gozo

Species spotlight X

Many members of the family Ferussaciidae tend to adopt subterranean or cavernicolous lifestyles. One such species may be found living in areas of clayey soil along the cliffs and beaches of Mellieħa; this is the small and elusive Hohenwartiana hohenwarti (Rossmässler, 1839), which at first glance resembles its relative Ferussacia folliculum (Gmelin, 1791).

Hohenwartiana hohenwarti (Rossmässler, 1839)
Għajn Tuffieħa, Malta

In contrast to Ferussacia, however, the elongated shell of Hohenwartiana is light and thin enough to render the internal organs clearly visible. The streamlined shape allows the animal to easily navigate around the clay fragments in which it lives. After the death of the animal, the shell turns an opaque white and disintegrates relatively quickly.

The specimen above was retrieved from clay for photographic purposes and replaced quickly. My hand in the background gives an idea of the specimen's size.

It's a snail's life...

Click on image for a larger view.

Species spotlight IX

Tudorella melitense (Sowerby, 1847)
Xlendi, Gozo

Tudorella melitense (Sowerby, 1847) is the only snail with an operculum ('door') which is native to the Maltese Islands. Under a 'biological species definition' it may be considered to be a local variety of Tudorella sulcata (Draparnaud, 1805), which also occurs in Sicily; Pfenninger et al. (2010)*, in their work on the DNA of Tudorella, consider it a lineage which is only found in the Maltese Islands.

Għajn Tuffieħa, Malta

The shell is very variable, and may be orange, white or purple, with or without bands.

Għajn Tuffieħa, Malta

*Pfenninger, M., Véla, E., Jesse, R., Arantzazu Elejalde, M., Liberto, F., Magnin, F., Martínez-Ortí, A., 2010. Temporal speciation pattern in the western Mediterranean genus Tudorella P. Fischer, 1885 (Gastropoda, Pomatiidae) supports the Tyrrhenian vicariance hypothesis. Molecular Phylogenetics and Evolution, 54: 427-436.

Species spotlight VIII

Oxychilus draparnaudi (Beck, 1837)

Buskett, Malta

Today's featured species is a small to medium-sized snail characterized by a brown, glossy and rather flat and fragile shell. It inhabits damp substrates such as compost or leaf litter in gardens or the compact soil beneath stone boulders. The animal is a distinctive blue-grey and is an active predator on other snails.

Oxychilus is a highly speciose genus distributed throughout Europe and the Near East.

Pembroke, Malta

Stone spiral

Cypraea sp.
Chattian, Oligocene

Lower Globigerina Limestone, Birżebbuġa, Malta

Species spotlight VII

Eobania vermiculata (Müller, 1774)
Żurrieq, Malta

The steppe areas of Malta are frequently populated by large snails from the family Helicidae, amongst which this species, Eobania vermiculata, commonly prevails. The shape and pattern of the shell is highly variable. In Malta, this is not a species utilized for food, unlike in the rest of Europe.

Rabat, Malta

Shell identification:

• large thick shell
• white base colour
• frequently banded
• flared lip

A contribution to 'Sagħtar'

Sagħtar is a students' magazine in its 37th year of publication. This month's issue includes information on some snails found in the Majjistral Nature & History Park. This article was written by Annalise Falzon from Nature Trust Malta and features a couple of my photographs. (click on image to view in full size)

Species spotlight VI

Xerocrassa meda (Porro, 1840)
Santa Venera, Malta

One of the commonest snails in Maltese gardens is this medium-sized species that apparently does not mind living in human-influenced habitats, actually preferring cultivated patches to the Mediterranean garigue so beloved of its other relatives. It might have originally been a Maltese and South-Sicilian endemic, eventually spreading to other Mediterranean islands by human intervention.


X. meda is one of two species in the genus Xerocrassa in Malta, which is sometimes treated as a synonym of Trochoidea, but which actually presents anatomical differences from that genus and is herein treated separately following the AnimalBase entry.

Shell identification

• 6-8mm
• pale brown or cream colour with darker bracket-shaped stripes
• aperture with a slight pinkish colour
• umbilicus pin-point shaped

Species spotlight V

Deroceras panormitanum (Lessona & Pollonera, 1882)
Żejtun, Malta

This is another slug described by the same folks who named yesterday's featured species. It is a south-west Mediterranean species which has since spread to most of Europe, North America and elsewhere. It can be distinguished from other Maltese slugs by its chestnut-pink colour, smaller size (about 2-3cm) and a fingerprint-like pattern on its back. A very similar species, Deroceras golcheri Regteren Altena, 1962 is endemic to Malta but is much rarer, and in places where it occurs with D. panormitanum, differences in colour and size are constant and consistent. D. golcheri also has a black mark near its pneumostome (respiratory opening, visible in both pictures) which D. panormitanum lacks.

Deroceras also has an internal shell.


Pictures are of the same individual.

Identification

• small fast-moving slug
• pinkish or pale brown
• mucus transparent
• fingerprint pattern on back
• no black mark near respiratory opening

Species spotlight IV

Lehmannia melitensis (Lessona & Pollonera, 1882)

Mdina, Malta

Lehmannia melitensis (Lessona & Pollonera, 1882) is a slug and thus appears shell-less, though a thin shell called limacella is present inside the body of the animal. This slug seems to be prevalent in the areas from Ta' Qali up to Rabat and varies from very light grey to almost black. It is similar to another more common slug called Milax nigricans (Philippi, 1836), which, however, has an angled dorsal side.

Lehmannia melitensis (Lessona & Pollonera, 1882)
Buskett, Malta

L. melitensis is distributed throughout Malta, Sicily, Sardinia and other places. Maltese specimens are usually greyer than those from other places. More information on this species and its congener Lehmannia valentiana (Férussac, 1822) may be found here.

Identification

• grey or black
• dark stripes running along its upper body
• fingerprint pattern on back
• rounded back

Species spotlight III

Lampedusa imitatrix (Böttger, 1879)
Mtaħleb, Malta

The clausiliid genus Lampedusa is endemic to Malta and the island of Lampedusa. In Malta it consists of two species, both of which are restricted in occurrence and live solely in highly calcareous habitats. The long and thin shell is characteristic of the family to which these snails belong. The picture shows a group of Lampedusa imitatrix (Boettger, 1879) individuals aestivating in Mtaħleb together with one (distant) relative - Cantareus aspersus (Müller, 1774). The other Maltese congener Lampedusa melitensis (Caruana Gatto, 1892) will be encountered later; while the third and final species Lampedusa lopadusae (Calcara, 1846), endemic to another Mediterranean island, is the subject of this post.

Baħrija, Malta

Shell identification

• long and narrow shell
• shell top not broken
• ribbed
• more than two incomplete ribs on last whorl
• shell tapers down near opening

A walk around the Colosseum

The Amphitheatrum Flavium, better known as the Colosseum, is an iconic Roman era building in the centre of Rome. Ravaged by natural phenomena and looters throughout the centuries, it still stands towering above the city, and offers a wonderful opportunity to admire the architectural and engineering prowess of the ancient Romans.

In 1643, far before the advent of Linnaean taxonomy, a gent by the name of Domenico Panaroli decided to publish an inventory of the plants found inside the Colosseum after noticing several exotic (mainly North African) species inside and around it, resulting in the tome Plantarum Amphytheatralium Catalogus. Nowadays, the list of species from the Colosseum has grown to 684 species of plants (Caneva, 2003).

A humidity-loving moss, bearing sporangia (fruiting bodies) on stalks

Adiantum capillusveneris L., also found in Malta

Cymbalaria muralis G. Gaertn., B. Mey. & Scherb.

Of course, the ample vegetation offers much cover for my favourite invertebrates - snails. The most common ones present in soil were Eobania vermiculata (Müller, 1774) and a species of Cernuella (I have not yet decided which this is out of the confusing trio of C. virgata (Da Costa, 1778), C. cisalpina (Rossmässler, 1837) and C. neglecta (Draparnaud, 1805)). Later on, a few specimens of Papillifera bidens (Linnaeus, 1758) and Xerotricha apicina (Lamarck, 1822) were encountered amongst the ruins.

Cernuella sp.

Xerotricha apicina (Lamarck, 1822)

On a totally unrelated note, here's one of the modern day inhabitants of the Colosseum:

References:

Caneva, G., 2003. The Colosseum's use and state of abandonment as analysed through its flora. International Biodeterioration & Biodegradation, 51: 211-219.
Panaroli, D., 1643. Jatrologismi sive medicae observationes quibus additus est in fine Plantarum Amphytheatralium Catalogus. Typis Dominici Marciani, Rome.

Species spotlight II

Truncatellina callicratis (Scacchi, 1833)
Lunzjata, Malta

Truncatellina callicratis (Scacchi, 1833) is the smallest landsnail in Malta and the only recent representative of its family, the Vertiginidae. Never exceeding 2mm in length, it is found in large (though localized) populations in leaf litter of trees such as Ceratonia siliqua (Carob Tree/ Ħarruba), such as the one below in Lunzjata, Rabat:

The species is probably under-recorded due to its small size and habitat restrictions.

Shell identification

• about 2mm
• about as twice long as it is wide
• compact cylindrical shape

Species spotlight I

Ferussacia folliculum (Gmelin, 1791)
Munxar, Għawdex

Ferussacia folliculum (Gmelin, 1791) is a common tiny snail which lives in a variety of habitats, as long as sufficient cover from the sun's heat is present. It is usually found in moderate to large-sized populations, such as the one composed completely of juvenile individuals, as shown below (photo taken in Pembroke, Malta):

The shell is brown and quite glossy. The yellowish colour visible in the above picture is imparted by the snail's foot, as is shown better thanks to the 'one that got away':

Shell identification

• glossy brown shell
• transparent when fresh
• large last whorl
• tall and pointed
• relatively thick shell
• tooth at the base of aperture