Pseudotriakis is currently considered a mono-specific genus. Yano and Musick (1992) showed that morphometric characters used to separate Pacific Pseudotriakis acrales Jordan & Snyder, 1904 (described from Japan) from Atlantic P. microdon de Brito Capello, 1868 did not differ significantly, and these authors confirmed P. acrales as a junior synonym of P. microdon. However, sequencing the mitochondrial NADH2 gene, Straube et al. (2013) found that P. microdon samples from Taiwan formed a distinct cluster compared with samples from the Madagascar Ridge and the Mid-Atlantic Ridge. This suggests the existence of distinct populations requiring further taxonomic examination and the possibility that P. acrales is a valid species for the Northwest Pacific population.

The False Catshark (Pseudotriakis microdon) is a large (296 cm total length) wide ranging deepwater shark with most records from the Northern Hemisphere (it appears rarer in the Southern Hemisphere). It may be cosmopolitan, but as yet has not been recorded from the Northeast and Southeast Pacific. It occurs on the continental and insular slopes at depths of 100–2,430 m. At present the species is of no interest to fisheries but is taken sporadically as bycatch in deepwater longline and trawl fisheries. Deepwater fisheries are generally expanding globally, and given the biology of this species, bycatch of this uncommon to rare shark may be of concern for any localized populations in areas where fishing may be concentrated, such as deepwater reefs or seamounts. However, the global population trend is suspected to be stable based on extensive refuge in deep water outside of current fishing activities. There is nothing to infer or suspect population reduction at this time, and the False Catshark is assessed as Least Concern.

A wide-ranging species, the full extent of occurrence of the False Catshark is uncertain as records are sporadic. Records from the Southern Hemisphere are relatively scarce and the species most likely occurs at more locations than presently recorded (as evidenced by new records in previously unrecorded locations over the last decade, e.g., Friedlander et al. 2014, Brooks et al. 2015, Clerkin and Ebert 2018, Koeda et al. 2021).

The species has been recorded in the following regions and locations: Northwest Atlantic; Canada, New York to New Jersey; Western Central Atlantic: The Bahamas; Northeast and Eastern Central Atlantic: Atlantic Slope and seamounts off Iceland, France, Portugal, Spain, Madeira, Azores, Canary Islands, Senegal to Guinea and Cabo Verde; Southeast Atlantic: Valdivia Seamount west of Namibia; Western Indian Ocean: Madagscar and Seychelles (Aldabra Island group) and isolated locations in the Southwest Indian; Northwest Pacific: Japan (southern Honshu and Okinawa), Ritto Seamount (Western Mariana Ridge), and Taiwan; Eastern Indian Ocean: Australia (Cape Leeuwin, Western Australia) and eastern Indonesia; Western Central Pacific: Coral Sea, off Mackay, Queensland; Southwest Pacific: New Zealand (Three Kings Ridge and Hikurangi Trough, east of Mahia Peninsula) and Pitcairn Islands; and Central Pacific: Hawaiian Islands (Stewart and Clark 1988, Yano 1992, Yano and Musick 1992, Allen and Cowan 1995, Gilhen and Coad 1999, Stewart 2000, Baranes 2003, Kyne et al. 2005, King et al. 2006, Menezes et al. 2009, Friedlander et al. 2014, Brooks et al. 2015, Clerkin and Ebert 2018, Ebert et al. 2021, Koeda et al. 2021).

There is no information available on population size, structure, or trend although it is seemingly uncommon or rare wherever it occurs in its deepwater habitat. The general irregularity of reported or observed encounters with fisheries suggests that it is uncommon or rare, it is beyond the depth range of many fishing operations, and/or it has low catchability in many fishing gears. There is nothing to infer or suspect population decline at this time.

The False Catshark is demersal on the continental and insular slopes, including around seamounts, troughs, and deepwater reefs from depths of 100–2,430 m (Ebert et al. 2021). This species is occasionally recorded on continental shelves including in shallow water. This may be abnormal behaviour or where submarine canyons extend close to shore (Ebert et al. 2021). It reaches a maximum size of 296 cm total length (TL) (female), 295 cm TL (male); males mature at about 260 cm TL, females at about 265 cm TL (Yano 1992, Ebert et al. 2021). Size at birth is estimated between 120 and 150 cm TL (K. Yano, unpubl. data 2004). Reproduction is viviparous with oophagy. Reported litter size of this species is two (Taniuchi et al. 1984, Yano 1992, Stewart 2000). Gestation period is unknown, but is presumed to be >1 year and possibly more than 2 or 3 years (K. Yano, unpubl. data 2004).

Localized populations of this large shark could be rapidly depleted if it began to be captured more regularly, however, at present it is of little interest to fisheries and is only taken as sporadic bycatch.

Most specimens of this species have been taken on deep-set longlines or in deepwater demersal trawls. Among the specimens reported in the literature as taken from commercial fishing operations, individuals have been captured as bycatch of trawls for Atlantic Halibut (Hippoglossus hippoglossus) in the North Atlantic Ocean (Gilhen and Coad 1999) and Orange Roughy (Hoplostethus atlanticus) in the southern Indian Ocean (Allen and Cowan 1995), deep longlines targeting black scabbardfish (Aphanopus spp.) off the Canary Islands in the Eastern Central Atlantic (Pajuelo et al. 2010), developmental fishing surveys for demersal longline fisheries in the North Pacific Ocean (Yano 1992), targeted shark longline fishing in eastern Indonesia (Yulianto et al. 2018), and exploratory deepwater dropline fishing targeting deepwater reef fishes, particularly Flame and Ruby Snapper (Etelis spp.) and Bar Cod (Epinephelus spp.) off Queensland, Australia (Kyne et al. 2005).

The species is not reported to be utilized.

There are no conservation measures in place for this species. Deep-sea marine protected areas would be important in preserving habitat of this and other deepwater species. It likely occurs in deeper areas of the Australian Marine Park network. Further research is needed on population size and trends, and life history, and catch rates should be monitored.