Publications - update 3

One of the several lessepsian species colonizing areas of the Mediterranean is Brachidontes pharaonis, a bivalve with the ability to form dense mytilid mats over a range of different mediolittoral substrata. Since its initial observation from the Maltese Islands in the early 1970s, the species has consolidated its presence all over the archipelago. Close examination of the entire length of the Maltese shoreline was conducted to collect quantitative and qualitative data on the mytilid and on dominant accompanying macrofaunal and macrofloral species, in what represents the first comprehensive mapping of an allochthonous species within an island territory. Brachidontes pharaonis was found to have colonized most of the northern and eastern coastal stretches of the island of Malta, preferring limestone substrata in inlets with limited wave exposure and affected by high marine concentrations of hydrocarbons and other pollutants, where it reached individual abundances exceeding 1000 individuals per square metre.

A cluster of Brachidontes pharaonis (Fischer, 1870) from a Globigerina limestone location on the Ta' Xbiex shore. Barnacles, patellids, chitons and coralline algae are also visible.

Reference:

Cilia, D. P. & Deidun, A., 2012. Branching out: mapping the spatial expansion of the lessepsian invader mytilid Brachidontes pharaonis around the Maltese Islands. Marine Biodiversity Records, 5 (e28): 1-8. DOI link

Publications - update 2

The invasive Melanoides tuberculata (Müller, 1774), a freshwater and brackish water snail, is reported from Mosta and Baħrija in Malta. Shells from these populations are morphologically distinct from a population at Salini first recorded in 1981.

Shells of Melanoides tuberculata from Malta - specimens from Baħrija, Mosta and Salini.

Reference:

Cilia, D. P., Sciberras A. & Sciberras J., 2012. Two non-indigenous populations of Melanoides tuberculata (Müller, 1774) (Gastropoda, Cerithioidea) in Malta. MalaCo, 9: 4 pp. accessible here

Entomological Society of Malta - vol. 4 launch

Last Friday saw the launch of the 4th volume of ESM's excellent series of papers dealing with, as the name of the society implies, the entomology of the Maltese islands and their biogeographic context.

The event was held under the patronage of His Excellency Dr. George Abela, and three society members (including its chairman) delivered short speeches on the importance of scientific research, peer reviews, funding and the maintenance of high publication standards. 

The scope of the talks ranged from the general, all-encompassing importance of works by luminaries such as Max Planck and Thomas Kuhn, to the specialized methodologies employed by scientists dealing in what the public may perceive as the "dinja stramba ta' dud, nemel u nsetti oħra" (lit. strange world of bugs, ants and other insects).

On to the main issue at hand - and its contents. This collection contains:

1) a catalogue of the aphid species occurring in Malta, with 48 new records, together with a list of aphid parasitoids, with three new records, and a new record of a coccid

2) observations and records of tachinid, rhinophorid and cecidomyiid flies from Malta and other Mediterranean areas

3) observations and records of nepticulid and pyralid moths from Malta

4) a catalogue of Maltese Scarabeoidea with eight new records, with a discussion on possible extinction mechanisms for these very interesting beetles

5) short features aimed at the younger demographic

A sample illustration - Scarabaeus (Ateuchetus) semipunctatus Fabricius, 1792 and Scarabaeus (Ateuchetus) variolosus Fabricius, 1787

The website was not updated in time for the launch, therefore for more information on the society please contact

Dr. David Mifsud
Entomological Society of Malta
P. O. Box 9
Marsa, MRS1000
Malta

Death of a Phoenix

Palms are a common sight in Malta, with the warm temperatures affecting the islands throughout most of the year being a perfect catalyst for their growth and proliferation. This said, indigenous species amount to just one - the low-growing, bushy Chamaerops humilis L., now practically extinct in the wild.

Chamaerops humilis L., photographed by Aron Tanti

The recent invasion of the red palm weevil Rhynchophorus ferrugineus (Olivier, 1790) has affected several of the ornamental palms of the genus Phoenix.

Rhynchophorus ferrugineus (Olivier, 1790) from www.cm-oaz.pt

 
The date palm, Phoenix dactylifera L., is a historically important North African species that may be distinguished by leaves arranged in wide silvery fronds. The picture beneath shows this species of palm affected by the Rhynchophorus beetle.

Phoenix dactylifera L. affected by the red palm weevil in Santa Venera, Malta

Phoenix sp. in Rome, Italy, with the one on the right showing symptoms of red palm weevil infestation

Phoenix canariensis Chabaud is a Canarian endemic which is frequently planted around the Mediterranean, not least in Malta. Unfortunately it is also affected by the weevil in question and several stately specimens from around the island have been destroyed.

Phoenix canariensis Chabaud in the main road of Floriana, Malta

The inhabitants of Tenerife certainly make excellent use of their endemic palm species!

New marine biology papers

1. Mifsud, C. & Cachia, C., 2011. New additions and corrections, with annotations, to the check-list of the marine Mollusca of the Maltese Islands. Triton, 23: 10-18.

This paper is an addendum to the four volumes on marine mollusc records from the Maltese Islands by Cachia, Mifsud & Sammut (1991; 1996; 2001; 2004 - see full references below). In this paper, 99 additional records are mentioned together with a number of corrections of previous records.

Of particular interest is a second species of Paludinella for Malta. This minute snail is rare and lives in marshes, and previously only Paludinella littorina (Delle Chiaje, 1828) was known to occur. Samples from Salina Bay have yielded some individuals of Paludinella sicana (Brugnone, 1876).

A comparison of Paludinella sicana (Brugnone, 1876) and Paludinella littorina (Delle Chiaje, 1828), pictures taken from the Natuurhistorisch Museum Rotterdam collection

Also worthy of mention is the first Central Mediterranean record of the pyramidellid Leucotina eva Thiele, 1925.

2. Deidun, A., Galea Bonavia, F. & Schembri, P. J., 2011. Distribution of Tylos spp. in the Maltese Islands and population dynamics of Tylos europaeus. Journal of Coastal Research, SI 57: 369-372.

Tylos is a genus of woodlice, two species of which - Tylos europaeus Arcangeli, 1938 and Tylos sardous Arcangeli, 1938 - occur on two sandy beaches on island of Gozo. This paper examines their habitat and gives an account of yearly fluctuations in the former's population.

References:

Cachia, C., Mifsud, C. & Sammut, P., 1991. The Marine Shelled Mollusca of the Maltese Islands Part 1: Archaeogastropoda. Malta: Grima Printing & Publishing Industries; 112 pp.

Cachia, C., Mifsud, C. & Sammut, P., 1996. The Marine Mollusca of the Maltese Islands, Part 2: Neotaenioglossa. Netherlands: Backhuys Publishers; 228 pp.

Cachia, C., Mifsud, C. & Sammut, P., 2001. The Marine Mollusca of the Maltese Islands Part 3: Sub-class Prosobranchia to sub-class Pulmonata, order Basommatophora. Netherlands: Backhuys Publishers; 266 pp.
Cachia, C., Mifsud, C. & Sammut, P., 2004. The Marine Mollusca of the Maltese Islands Part 4: Caudofoveata, Solenogastres, Bivalvia, Scaphopoda and Cephalopoda. Netherlands: Backhuys Publishers; 270 pp.

The Roman Villa in Żejtun

Today's edition of the Times of Malta reports that remains of a Roman Villa in Żejtun will be cleaned up and conserved. The following are some pictures taken in 2009 at this site. 

It is interesting to note that, in the course of about two millennia, yellow colonies of the lichen Xanthoria parietina have colonized most of the limestone blocks available, and only rarely are they found growing on the earthenware tiles. This is probably a direct effect of the materials' porosity relative to each other.

A collection of lichens

Lichens are a group of fungi that have, during the course of evolution, entered a mutual association with algae or cyanobacteria, resulting in a complex relationship that benefits both organisms and allowing them to colonize habitats which would otherwise be inaccessible to the fungus or to the algae by itself.

These habitats may range from bare rock to tree trunks; considerable variety is amply demonstrated even in a relatively small area such as the Buskett woodland, where all the following photographs were taken.

Caloplaca sp., a distinctive yellow lichen which covers bare rock

Ramalina durieui, found mostly on thin branches of pine (Pinus halepensis) and cypress (Cupressus sempervirens)

Another 'leafy', cypress-loving species

This lichen appears to prefer dead bark of the pine tree

A black lichen using rock as its substrate. The green growth consists of moss, which, unlike lichen, is a true plant.

A white lichen on rock.

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 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

An alien fish in Maltese waters

A research paper regarding the first recorded occurrence of the Pacific fish Oplegnathus fasciatus (Temminck & Schlegel, 1844) in Malta was recently published in the journal Acta Ichthyologica Et Piscatoria.

Oplegnathus fasciatus (Temminck & Schlegel, 1844)
Valletta, Malta

photo by John Attard

More information may be found here, while the work in its entirety may be accessed here.

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

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