Caddidae

Banks, 1893

Large-eyed Harvestmen

Caddidae is a of and the sole family in the superfamily Caddoidea. The family contains only two extant in the Caddo, following taxonomic revision that removed previously included genera to other families. These tiny harvestmen have body lengths of 1–3 mm and exhibit a disjunct distribution across eastern North America and East Asia.

Caddo pepperella 142473571 by Shahan Derkarabetian. Used under a CC BY-SA 4.0 license.

Caddo agilis 19405843 by Shahan Derkarabetian. Used under a CC BY-SA 4.0 license.

Caddo agilis front close up by Marshal Hedin. Used under a CC BY-SA 2.0 license.

Pronunciation

How to pronounce Caddidae: /ˈkadɪˌdiː/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other Eupnoi by their minute size (1–3 mm body length) and phylogenetic placement. The Caddo is the only extant genus in the family following removal of Acropsopilio, Austropsopilio, Caddella, and Hesperopilio to other families or uncertain placement. Specific identification requires examination of palpal and genital .

Images

Appearance

Body length between 1 and 3 mm. As , they possess a and without a narrow waist, and characteristically long, slender legs relative to body size.

Distribution

Disjunct distribution: eastern North America (USA, Canada) and East Asia (Japan, South Korea, Russian Far East including Primorskii Krai and Kuril Islands). The northwestern boundary in Asia is Primorskii Krai, Russia.

Human Relevance

The name derives from "Caddo," a North culture, people, and language.

Similar Taxa

AcropsopilionidaePreviously included in a wider concept of Caddidae; restored to separate status and placed in suborder Dyspnoi rather than Eupnoi.
NemastomatidaeAnother of small-bodied Dyspnoi ; Caddidae is distinguished by its placement in Eupnoi and unique phylogenetic position.

Misconceptions

Historical treatments included many more (Acropsopilio, Austropsopilio, Caddella, Hesperopilio) under a broad concept of Caddidae. These have been removed based on phylogenetic studies, reducing Caddidae to a single genus with two extant .

More Details

Taxonomic history

The underwent significant revision after Shear (1974). Previously grouped with Gondwanan distributions (South America, Australia, New Zealand, southern Africa) have been transferred to other families or remain of uncertain placement, fundamentally altering biogeographic interpretations.

Phylogenetic divergence

Caddo agilis and C. pepperella diverged phylogenetically before acquiring their current disjunct, distributions in Japan and North America, indicating that their geographic pattern resulted from rather than vicariance alone.