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

Scales in stone

From the 12th of this December to the 16th of January 2011, Heritage Malta is organizing an exhibition on fossil fish from the Maltese Islands at the National Museum of Natural History (NMNH) in Mdina.

Such remains are of high importance, both palaeontologically and historically, being featured in several scientific publications including palaeoecological studies and new taxonomic descriptions. Most are also extremely rare, with fragile bones that do not fossilize easily.

To whet appetites, here's a taster of what the NMNH collection of fossil fish includes:

Stereodon melitensis Owen, 1864

Myliobates sp.

Holocentrum melitense Woodward, 1887

Best wishes for 2011

Islands of the Maltese Archipelago - Part I

Filfla

Southermost island of the Maltese Archipelago

General's Rock

Westernmost island of the Maltese Archipelago

Entomological Society of Malta - vol. 3 launch

The launch of the annual third volume of papers in the excellent series by the Entomological Society of Malta took place this evening at the sumptuous Casino Maltese in Valletta. The occasion consisted of short talks and a presentation on what is included in this journal, entitled Bullettin of the Entomological Society of Malta.

The contents of this issue are:
1) A first Maltese record of a non-pollinating wasp of Ficus sp.
2) A review of the tineid moths from Malta including the description of a new species - Euthria melitensis Gaedike & Zerafa, 2010
3) A review of the Maltese Heteroptera with seven new records
4) A survey of potentially disease-carrying mosquito species in Malta
5) A review of the weevils of the Maltese Islands with 51 new records
6) A section aimed at young entomologists

Another moth was described in the second issue of the journal from 2009; this was Stichobasis postmeridianus, shown below. Both are, as far as is known, endemic species.

Stichobasis postmeridianus Zerafa & Sammut, 2009

For information on how to obtain Volume 3 or any of the previous ones please contact:

Entomological Society of Malta
P. O. Box 9
Marsa MRS1000
Malta

Waiter, there's a snail in my paella

While spending a few days in València, Spain, I was surprised at the general lack of snails and slugs even in the grassiest of places along the riverbanks. A cursory search in the huge public park resulted in the finding of just three Cochlicella barbara (L., 1758) specimens on a nightly 'romp', but then, the well-maintained and intensely cultivated area was perhaps not the optimum environment for worthwhile molluscan discoveries.

Part of Valencia from above

The Valencians have many exquisite traditional dishes, frequently making ample use of seafood and landsnails. In a particular market, I was surprised to see that three species of the latter are farmed and packaged separately for consumption. These are Theba pisana (Müller, 1774), Otala punctata (Müller, 1774) and Cantareus aspersus (Müller, 1774) (pictured beneath in respective order). All three species are also present in Malta, yet here only the latter is consumed.

I later found a sub-adult Otala punctata in my Valencian paella take-away.

Happy Halloween!

Felis catus (L., 1758) var. maleficus

A rare tree snail

From Sumatra, Indonesia - this is original footage one of the rarest tree snails known, Amphidromus (Goniodromus) bulowi Fruhstorfer, 1905 - only rediscovered a century after its original description in 1905 and unfortunately well on its way to extinction.

Video uploaded thanks to Mr. John Abbas.

New paper published

Pseudotachea splendida (Draparnaud, 1801) - Qormi, Malta.

A paper of interest to the readers of this blog has just been published in this month's issue of the journal Triton.

Cilia, D. P., 2010. A note on shells of Pseudotachea splendida (Draparnaud, 1801) in the Maltese Islands (Central Mediterranean). Triton, 22: 33-34.

Abstract: Shells of the western European helicid Pseudotachea splendida (Draparnaud, 1801) are recorded from a plant nursery in Malta.

The private life of snails

This event is happening at the Majjistral Nature and History Park on the 21st of November. Please click on the picture for a better view!

Tourism & Biodiversity

The 27th of September is World Tourism Day. The Malta Tourism Authority is celebrating this year's theme - "Tourism & Biodiversity" - by issuing a set of four stickers which feature typical organisms of the Maltese Islands.

Understandably, the variety of flora and fauna pictured is diverse and includes a plant, two invertebrates, and two vertebrates. These are, respectively:

1. Capparis orientalis Veillard (noted on the sticker under the synonym Capparis spinosa L.);
2. Papilio machaon melitensis Eller, 1936 (an endemic butterfly);
3. Echinaster sepositus sepositus (Retzius, 1783);
4. Epinephelus marginatus (Lowe, 1834) (noted on the sticker under the synonym Epinephelus guaza L., 1758);
5. and the Maltese national bird Monticola solitarius L., 1758.

Please click on image for larger version!

Sex! Murder! Cannibalism!

It looks like the blurb for some low-budget 70's horror flick, but such storylines are relatively commonplace in the arthropod world. Argiope lobata Pallas, 1772 is a spider displaying extreme sexual dimorphism - the small male is seldom seen, but the female is one of the largest arachnids found in the Maltese Islands.

As in some other arthropods of the sexually dimorphic ilk (e.g. praying mantises and crabs), the hapless male is frequently cannibalized by the female (seen in the pictures above) following mating. It is mainly seen in humid and shaded habitats suspended head downwards from its very strong web, patiently waiting for prey.

A hardy egg sac like the one below is subsequently constructed nearing the end of the summery season. Hundreds of small spiders hatch and spend the winter inside this sac, emerging in spring.

The images in this post come courtesy of Mr. David Dandria and Mr. Patrick Tabone.

New section

The picture on the right hand column of this blog labelled 'On S. E. Asian gastropods' now leads to a new page, where I will be posting my work on snails from the region of South-East Asia.

Updates will also be listed accordingly on this main blog section.

Amphidromus sekincauensis Dharma, 2007 - South Sumatra

Tideline barnacles

Virtually all rocky seashores in Malta sport millions of these unassuming, pyramidal entities that close or open to feed or reproduce depending on the availability of seawater from tide or waves. They are barnacles mostly belonging to the species Chthamalus stellatus Poli, 1791, though other species of Chthamalus are also present on Maltese shores.

As seen in the photograph above (lower right hand corner and upper centre), dead individuals leave behind calcareous volcano-shaped cavities which may be used as a refuge by other intertidal organisms, such as the amphibious and very interesting snail Melarhaphe neritoides (L., 1758) or even other crustaceans such as amphipods. The photograph was taken at Dwejra, Gozo, during receding tide. On the other hand, the photograph below shows completely dry specimens from Buġibba, waiting for the presence of water to resume any activity.

Scorpion, interrupted

I (unintentionally) interrupted this scorpion at Għajn Tuffieħa while it was feasting upon the remains of a fellow arthropod - a hapless woodlouse, which can be seen still attached to the scorpion's jaws in the lower picture. A few seconds after being discovered, the scorpion released the morsel and assumed a compact, defensive stance, remaining utterly immobile until yours truly decided to leave it in peace and restore its stony hideout to its original place.

Only this species of scorpion exists in Malta. It is the small Euscorpius sicanus (Koch, 1837), also found on other Mediterranean islands.

Brocktorff's Maltese fossils

Sir William Reid, Governor of Malta from 1851 to 1858, was a military official and amateur scientist whose interests eventually led him towards a study of meteorology and hurricanes. In a bid to encourage interest in the geology of the Maltese Islands, he published a book containing a few lithographs of fossils commissioned from an artist known only as 'Brocktorff' (Zammit Maempel, 2007).

This book remains very rare in libraries. In addition the well-known echinoids, Brocktorff illustrates remains of crustaceans (a crab), cartilaginous fish (the famous glossopetrae), and bony fish. The following are a some of the illustrated specimens, a few of which are in the National Museum of Natural History, Mdina.

'Schizaster Parkinsoni, Defrance' [*]

'Schizaster Desori, Wright' [**]

'Found at Casal -Luca-Krendi in the Year 1854' [***]

'Found near Casal Luca in the Year 1855'

'Shark's Tooth, with Stony Zoantharia - found near St. Thomas Tower, Malta' [****]

[*] Schizaster parkinsoni (Defrance, 1835)
[**] Schizaster desori Wright, 1855
[***] in contemporary Maltese: Casal Luca = Ħal-Luqa; Krendi = Qrendi
[****] St. Thomas' Tower, Marsaskala

References:

Reid, W., 1857. Maltese fossils lithographed for distribution with the view to encourage further investigation into the geology of the island. Malta: Valletta.
Zammit Maempel, G., 2007. Illustrators and their illustrations of Maltese fossils and Geology. Malta: Publishers' Enterprises Group Ltd.

Dissertation - A student’s guide to the geology of the Maltese Islands

The citation and abstract to my B. Ed. (Hons) dissertation have been added to the links on the right-hand side of this blog. The page can also be accessed through here.

A tenacious fern

Deep inside caves, plant life is either extremely scarce or otherwise totally absent, which is due to the fact that plants need sunlight in order to manufacture food and therefore survive. However, the occasional thin ray of light may sometimes manage its way through, and this is an opportunity upon which mosses and ferns capitalize without fail.

The picture above shows the common maidenhair fern (Adiantum capillusveneris L.) taking advantage of such an instance at Għar Ħassan. The scant sunlight and nutrient-poor limestone soil are enough for the small but hardy plant.

Adiantum is a feature of many 'traditional' Maltese gardens due to its preference for shaded areas. The vernacular name in Maltese is Tursin il-Bir (lit. water-well parsley). Of course, true parsley is a flowering plant, and has nothing to do with the species in question.

Sharks in Malta Part III - Close encounters of the third kind

Today I was surprised that virtually all of the Google searches leading to this blog consisted of the same three keywords: 'shark in Malta'. I attributed this sudden interest to some sensational news item about which I hadn't heard anything so far - and sure enough, one glance at the Times of Malta web portal explained everything.

Without further ado, here's the link to the relevant news item and the accompanying video. Non-Maltese speakers will be disappointed, though!

The Maltese flint

The silicate mineral quartz is, in addition to calcite, one of the commonest minerals on the earth’s crust. An amorphous (non-crystalline) form of this mineral, called variously chert (highly impure) or silex or flint (relatively pure), is found in certain strata of the Maltese rocks.

In a pure state, silicon dioxide is of a transparent colour. This can be seen in crystalline specimens of quartz found in volcanic rocks which are termed ‘rock crystals’. In Malta, nodules or blocks of this mineral contain many impurities mainly consisting of calcium carbonate and other salts; this depends on the parent rock in which they form and results in different colours and varying degrees of translucence.

In the Upper Coralline Limestone Formation, nodules of chert are highly calcareous, opaque and microcrystalline in nature. The impurities in these nodules impart a layered dark brown or charcoal colour. Such nodules are common at the Upper Coralline Limestone of Xemxija and Mistra.

Middle Globigerina Limestone outcrops in Baħrija and Mtaħleb contain usually large blocks of light greyish or khaki chert that intergrades with the limestone and fractures very easily (picture above). Very thin sections of this material allow light to pass through. The parts remaining embedded in the bedrock protrude out and are visible as slightly darker patches against the white limestone.

Middle and Lower Globigerina outcrops in north-central Malta (Mrieħel to Msida) also contain chert, albeit in a the very different form of small to medium-sized nodules. These are somewhat darker in colour, and correspondingly, the silicate material found here is of a light brown to reddish colour.

Odds and ends

Not much time on the laptop on my part has meant a lack of recent blog updates, and for this I do apologize profusely. In the meantime, I have been working on a couple of research papers, two of which which have been submitted and accepted, and some others which are still a long way from being final.

Meanwhile the summery world outside is buzzing with activity, as can be exemplified by the beautiful Xylocopa violacea (L., 1758) below.

This bee is also known as the carpenter bee due to the fact that its eggs are laid inside purposely-bored wood or stems. During my observations I have noticed that the Arundo donax reed is a favoured home for this species.

While the invertebrate world is teeming with insects, however, molluscan representatives are few and far in between, owing to the terrible heat of the Mediterranean summer. The non-marine gastropods that never need worry about this are, of course, those who call freshwater their home, like this Physella acuta (Draparnaud, 1805) from Chadwick Lakes:

Many natural freshwater bodies boast sizable populations of this snail. Other species are much rarer, such as these minute (3mm) Mercuria cf. similis (Draparnaud, 1805) from a Gozitan population:

Burst of purple...

... or indigo, lilac, anyway - whatever you want to call it. Cheirolophus crassifolius (Bertoloni) is much better known as Widnet il-Baħar, and it has been designated as the national plant of Malta. It is an endemic species with a troubled taxonomic history and embellishes cliffs with its beautiful blooms during most of summer. A very hardy plant which withstands highly alkaline soil, it has also been used as an ornamental and is frequently seen in roundabouts, public gardens and roads, though it remains very rare in the wild.

To read about the Maltese national tree please click here.

A pirate's cave

The 12th century legend goes that a Turkish pirate by the name of Ħassan, madly in love with a beautiful Maltese girl, abducted her and took her to live with him in a cave in the southern cliffs of Malta. The villagers soon realized this and were immediately off to rescue the girl, then give the Turk the punishment he deserved. Upon hearing their shouts, the defiant Ħassan pushed the girl down the cliffs to her death, and leapt after her before anyone could catch him.


The locality where this tragic tale is supposed to have taken place is, fittingly, called Għar Ħassan (Ħassan's Cave). It lies between Bengħisa and Ħal-Far, punctuating the Lower Coralline Limestone cliffs making up most of the area. Like many other caves in the Maltese Islands it is a phreatic tube formed by the dissolution of limestone in water, and this is very evident in the smooth appearance of the cave walls.


Għar Ħassan consists of a central large chamber, the accessible part of which measures about 60m. Two main paths intersect with the main one at about 20m into the cave; the one to the east (above) leads to another opening in the cliff-face while the one to the right narrows down, eventually becoming inaccessible. Some parts of the main tube are perennially wet and mainly soft calcite deposits can be seen in several places on the walls of the cave. Clayey soil, consisting of the insoluble components of limestone, covers the entire floor of the cave and is sometimes cemented in place by calcite from hard water dripping from the ceiling. Soil has prevented stalagmites from forming over the limestone floor.


A fault running along the main chamber, quite visible on the roof of the cave (above), probably contributed to to the formation of the cave by fracturing and therefore making the usually firm Lower Coralline Limestone far less resistant to water flow.