I - I n t r o d u c t i o n :

Gathering images and data on reliable specimens of Hollardops is one of the keystone efforts of this study. Well-documented and well-prepared specimens are extremely valuable for paleontological study. We will discuss below several essential criteria for accepting specimens examined and analysed. Each of the specimens must be reliably identified and appropriate for a morphological study. In the case of Hollardops, and Moroccan specimens in general, poorly prepared or flagrantly restored specimens must be avoided.

Specimens in this study must be species of Hollardops. Since there are numerous species of acastoid phacopines in the Devonian Moroccan trilobite fauna, it is possible that specimens of misidentified genera might be mistakenly submitted for consideration as specimens of Hollardops. These, for example, have been commonly misidentified as "Metacanthina barrandei" by fossil dealers in the past few years.

If you think your trilobite might be Hollardops, compare your specimen to the images of Hollardops specimens that are already posted on this website to initially confirm your identification. The specimens posted are good representatives of the genus and also in general are very well-prepared. Confirm that your specimen matches the literature diagnosis of Hollardops (after MORZADEC 1997, 2001):

Cephalon characterised by a strongly anteriorly dilated glabella, long genal spines, and only 10 thoracic segments. The pygidium has a narrow axis, with 10 to 14 rings, a Greenops boothi-type pleural segmentation (see here for more informations on pleural segmentation of Asteropyginae), broad pleural furrows, and 5 pairs of pygidial lateral spines, lappet-like*, flat on the ventral side.

*lappet = lobe or flap.

Hollardops is very clearly distinguished from the other genera of the Asteropyginae subfamilly by the development of only 10 thoracic segments (11 in other asteropygines). The adult exoskeleton is of typical size for the Asteropyginae. The cephalic segmentation of Hollardops is close to that of Greenops DELO.

A note on taxonomic priority of Hollardops : The genus Hollardops MORZADEC 1997 was published in April 1997; the descriptions of Philipsmithiana LIEBERMAN & KLOC and Modellops LIEBERMAN & KLOC were published in June 1997. The two genera of LIEBERMAN & KLOC are considered synonyms of Hollardops (Jell & Adrain 2003).

Line drawings of specimens can also be useful in assisting identification. This one was developed by Sam Gon III based on a few well-prepared specimen images :

Synthetogramm of Hollardops sp. © Sam Gon III

Now, I guess you know if your specimen might be included in this study; the next step is to check if there are any exclusion criteria that will be strictly applied.

.

1 - The lack of precise and reliable informations on the specimen locality.

If you don't know where your specimen was collected, your specimen is useless for scientific study.

Confirm the locality data with the source of your specimen. We might ask you his name too, to check if the seller is reliable. The more precise the information, the better. An example of typical locality data might be: Er Remlia Formation, Bou Dib, Algeria. This is barely sufficient precision (although better than nothing); this would be better: South of Tazoulaït, Northern Ma'Der, marno-calcareous stratum, 3 meters under the Er Remlia Formation (such precision for locality is rarely obtained)

2 - Ignorance of the preparator's name.

Without this information it is by no means clear if your trilobite is not a composite assemblage of two or more specimens, or worse, a very good fabrication. Not knowing the preparator also implies serious doubt about the specimen locality, extent and kind of restoration has been done and preparation methods employed. The name of the seller may often lead to the information on preparator.

Some of us may have beautiful trilobites in their collection that lack good locality or preparation data, and may think these rules overly strict, but most of you understand that such information is essential quality control, and appearence alone is not the only criterion. Some "average preparation grade" trilobites might perfectly well have their place in this study if they fulfill the data criteria.

If your trilobite seems to be a specimen of Hollardops, and you have documentation that fits the study criteria, please send a digital image of the dorsal exoskeleton to : Jean-Brice Gayet. He will confirm the identification and ask for additional images and information. This study is based on images and measurements. Participants will be asked to provide both kinds of data as part of their participation in the workgroup project.