Hollardops

Order:  PHACOPIDA  Salter, 1864

Suborder: PHACOPINA  Struve, 1959

Superfamily: ACASTOIDEA  Reijers, 1972

Family: ACASTIDAE  Delo, 1935

Subfamily: ASTEROPYGINAE  Delo, 1935

Genus HOLLARDOPS  Morzadec, 1997

The Early Devonian rocks of southern Morocco are world-famous for their beautifully preserved trilobites. Among them, the genus Hollardops is one of the most sought after by collectors. These trilobites are known for their spiny tails, large compound eyes, and their ability to roll up tightly. Hollardops lived during the Emsian stage (about 407–393 million years ago), and their fossils are found mainly in the Maïder and Tafilalt regions of the Anti-Atlas mountains.

What makes Hollardops fascinating for collectors is not just their striking appearance but also the variety of species discovered in Morocco. Identifying these species can be tricky, but with a focus on eye size, lens counts, and head and tail shape, you can start telling them apart.

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General Features of Hollardops

• Have 10 thoracic segments (instead of 11, which many relatives have).

• Possess large schizochroal eyes with individually set lenses, sometimes towering above the glabella.

• Pygidium (tail) has paired pleural lappets (little spines) that interlock when the animal rolled up.

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The Moroccan Hollardops Species and How to Recognize Them

Below you’ll find the main Moroccan species, with their distinctive traits and especially their eye morphology — a key identification feature.
Second important thing to remember is that any Moroccan trilobites have been mislabeled as “Hollardops mesocristata,” but that species does not occur in Morocco.

Hollardops angustifrons

• Eyes: Medium-sized, lens count not precisely known but estimated around 10–11 lenses per vertical file.

• Head: Narrow glabella (the “forehead” of the trilobite).

• Tail: Short triangular pygidial lappets; fine, dense tubercle pattern; no median node on the axis.

• Good starting species for comparison because of its slimmer head shape.

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Hollardops boudibensis (Morzadec, 2001, upper Emsian, Morocco)

• Eyes: Medium size, with moderate lens counts (~10 per file).

• Head: Long preglabellar field; S2 and S3 furrows straight but fading before they reach the sides.
  The eyes have 27 rows of max 6 (rarely 7) lenses.

• Tail: Shorter pygidial lappets than related species.
  The pygidial axis has 12 rings. The pygidial spines are wide, short and rounded.
  The pygidium is rather rounded.

• Can be separated from burtandmimiae by its more rounded cephalon and less extreme eyes.

Picture adjusted from and used with permission of trilowelt.de

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Hollardops burtandmimiae

• Eyes: Very large, towering above the glabella; lens counts not precisely measured, but clearly more elevated and prominent than in most species.

• Head: Sparse tubercles, especially near the front; anterior border strongly deflected downward.

• Other features: Long genal spines and broader thoracic axis.

• Easy to spot because of the dramatically tall eyes, giving it a “bug-eyed” look.

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Hollardops hyfinkeli

• Eyes: Small, with ≤10 lenses per vertical file; sit farther away from the sides of the head.

• Head: Broad outline, long preglabellar field, and a well-developed kite-shaped frontal auxiliary impression system (FAI).

• Tail: Pygidial lappets short and broad at the base; first two furrows curve sigmoidally.

• The small eyes make this species stand out compared to others.

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Hollardops klugi

• Eyes: Not well preserved in type specimens (which are mostly enrolled), but likely moderate in size.

• Importance: The earliest known Hollardops from Morocco (lower Emsian).

• Other features: Shorter pygidium; median nodes present on occipital and thoracic rings.

• Best identified by its stratigraphic position and primitive features.

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Hollardops kyriarchos

• Eyes: Around 30 vertical files with 9 lenses per file (smaller than in multatuli).

• Head: Less angular, with broader glabella; S3 furrows divergent (~135°), meeting the axial furrow further back.

• Tail: Smaller, denser tubercles compared to multatuli.

• Great example of how lens counts can separate species.

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Hollardops luscus

• Eyes: Likely intermediate in size and lens count, though detailed numbers are limited.

• Location: Found in the famous Walliserops layer at Timerzit (El Otfal Formation).

• Differentiation: Often compared with kyriarchos, but differs in eye position and certain tail features.

• If you find one in Timerzit beds with a medium eye, it could be luscus.

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Hollardops multatuli

• Eyes: About 31 vertical files with 11 lenses per file (larger than kyriarchos).

• Head: Angular outline, narrower glabella; S3 furrows less divergent (~115°).

• Tail: Sparser but larger tubercles compared to kyriarchos.

• A species where big eyes and sharper head outline give it away.

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Tips for Collectors

1. Always check the eyes first. Lens counts and eye size are some of the most reliable differences.

2. Compare the glabella shape. Narrow vs broad is a fast separator.

3. Look at the tail spines (lappets). Length and shape can confirm your ID.

4. Don’t trust every label. Many Moroccan trilobites have been mislabeled as “Hollardops mesocristata,” but that species is not reliably from Morocco.

Adjusted from Chatterton et all (2006)

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References

Bignon, A., Crônier, C., 2014. The systematics and phylogeny of the Devonian subfamily Asteropyginae (Trilobita: Phacopida). Journal of Systematic Palaeontology 12, 637–668.

Chatterton, B., Fortey, R., Brett, K., Gibb, S., McKellar, R., Trilobites from the upper Lower to Middle Devonian Timrhanrhart Formation, Jbel Gara el Zguilma, southern Morocco. Paleontographica Canadiana 25.

Morzadec, P. 2001. Les Trilobites Asteropyginae du Dévonien de l’Anti-Atlas (Maroc). Palaeontographica, Abt A , 262, 53-85.