Typhlichthys subterraneus

Girard, 1859

Southern cavefish

(Drawing by E.S. Damstra, published in Romero, 2003a).

Known Museum Specimens

^a This is, in reality, Amblyopsis rosae (Mayden and Cross 1983).

Acronyms for museum collections:

AMNH: American Museum of Natural History

ANSP: Academy of Natural Sciences of Philadelphia

ASUMZ: Arkansas State University Museum of Zoology (Jonesboro)

CAS: California Academy of Sciences

CMNH: Cleveland Museum of Natural History

FMNH: Field Museum of Natural History (Chicago)

INHS: Illinois Natural History Survey

KU: Kansas University

MCZ: Museum of Comparative Zoology, Harvard University

NLU: Northeast Louisiana University

UMMZ: University of Michigan Museum of Zoology

USNM: United States National Museum (Washington, DC)

YPM: Yale Peabody Museum, Yale University.

ZMUC: Zoological Museum of the University of Copenhagen

Picture courtesy of Danté Fenolio

Other Pictures:

http://www.fishbase.org/Photos/Pictures.cfm?picname=Tysub_u0.jpg

http://www.luciopesce.interfree.it/zoologia/fish.html

http://www.auburn.edu/academic/science_math/cosam/museum/musefish/holdings.htm

http://www.utexas.edu/depts/tnhc/.www/biospeleology/mocavelife/TN_001.JPG

http://www.utexas.edu/depts/tnhc/.www/biospeleology/typhlich.jpg

http://members.socket.net/~joschaper/wsocafish.html

http://animaldiversity.ummz.umich.edu/site/resources/native_fish_conservancy/Typhlichthys-subterraneus-1.jpg/view.html

http://www.conservation.state.mo.us/cgi-bin/mofwis/search.cgi?record=0100026&MATCH=exact

Morphological Characteristics

It reaches 90 mm of standard length (SL).  Large, broad head.  Fin ray counts is as follows: dorsal soft rays (total): 7-10; anal soft rays: 7-10; lacks pelvic fins.  10-15 branched caudal rays.  The number of vertebrae is 28-29.  Caudal fin with 0-2 rows of papillae and a vertical basal row.  Anus well in front of the anal fin in adults.  It has a port-cleithrum bone.

Troglomorphic Characters

Eye Condition:  Rudimentary eyes hidden under the skin.
Pigmentation:  Body depigmented with few non-functional pigment cells.
Scales:  Minute and embedded.
Swim (gas) bladder: They posses a swimbladder (Schubert 1993, p. 130).

Plastic responses: Under exposure to white light some individuals develop epidermal melanophores (Woods and Inger 1957)

Distribution

USA: Subterranean waters in two major disjunct ranges being separated by the Mississippi River: Ozark Plateau of central and southeastern Missouri and northeastern Arkansas; and Cumberland and Interior Low plateaus of northwest Alabama, northwest Georgia, central Tennessee and Kentucky and (possibly?) southern Indiana (ca. 37^o 00' N, 86^o 29' W). 

Woods and Inger (1957) noted that the type specimens of Typhlichthys wyandotte had been lost and the type-locality destroyed.  However, a well- like entrance into a cave, on the property of a car dealership in Corydon, Indiana, was discovered recently and is speculated to be the type-locality of Typhlichthys wyandotte (Lewis 2002).  That does not mean that this species is found in Indiana: a year-long study of the Binkley Cave System and associated caves in the Corydon area by Lewis and Sollman (1999) found only the related cavefish Amblyopsis spelaea. A survey of about 200 caves in the same drainage basin also failed to find Typhlichthys subterraneus (Lewis 1998).Poly and Proudlove (2004) reported that they had rediscovered the holotype of T. wyandotte (CAS 91988) and some of the syntypes of of T. orboni (CAS 78370, 91980, 91981, 91982) in the California Academy of Sciences collection.

A citation for Oklahoma is incorrect: it was based on a single, poorly preserved, 19.2-mm SL specimen from Cave Spring, Ottawa County.  Mayden and Cross (1983) reidentified the original specimen, and one specimen collected later from the same locality, as Amblyopsis rosae, the Ozark cavefish. Their identification was based on six characters utilized to distinguish Typhlichthys from Amblyopsis.

Habitat and Ecology

They are found in rather deep water tables, beyond 200 m in depth.

Mostly lentic but also in pools of streams at or near water table.  Found in caves which are near the water table and are therefore more uniform than other amblyopsid caves. (Noltie & Wicks 2001).  They seem to be attracted to point sources of water efflux (Schubert and Noltie 1995).  Microhabitat selection by captives was studied by D. Noltie and A. Schubert in Missouri in the early 1990s (Figg 1993).  They show

The population of  in Wayne County, Missouri, has been estimated to be at least 90 individuals (Pflieger 1997).  Most populations include fewer than 150 individuals.

An individual of T. subterraneus was reported in Key Cave, Alabama, the only known cave inhabited by another species of amblyopsid, Speoplatyrhinus poulsoni (Kuhajda and Mayden, 2001).

Detailed Distribution

Range map of the distribution of known cavefish (Amblyopsis rosae and Typhlichthys

Food and Feeding

Feeds mostly on copepods (60-80 of its diet), amphipods, isopods, decapods, cladocerans, non-annelid worms and aquatic insects (Poulson 1961).  Schubert (1993) found that the daily mean consumption rate is 2.68 " amphipods/day or 11.8 mg amphipod/g fish/day.

Physiology

This species has about 28,600 lamellae on gill filaments, their gill area is 169.1 mm² and its metabolic rate is 0.016 O₂ ml g^-1 h^-1.  Their branchial volume is 50 mm³, ventilation frequency is 19 (15-21), and amplitude 0.8 (0.4-1.0).  All these values as well as their thyroid activity fall into the median for other species of amblyopsids (Poulson 2001).

Reproduction and Development

Branchial (i.e., gill chamber) brooding is possible because of the position of the jugular vent and the size and shape of the gill chamber (Poulson 1963) but this has yet to be proven.  As many as 50% of the adult female population may breed in any one year.  Breeding probably occurs in late spring (April and May) in association with rising water levels (Robison and Buchanan 1988).  It is long-lived and slow growing.  They develop the first scales at three months of age and the first annulus at 7-10 months.  They become reproductively active at 22-24 months of age (Poulson 1961).

Fecundity is very low, perhaps fewer that 50 ova per female.  It takes about two months for free swimming young to develop from the zygote stage.  Females display parental care.  They may live for decades rather than years (Noltie and Wicks, 2001).  They have low reproductive capacity. A study of reproductive ecology and microhabitat selection was initiated in Missouri in 1991 (Figg 1991).

Nervous System

They show enlarged olfactory and acoustico-lateralis in their brain as well as reduced optic centers.

They have numerous neuromasts with round bulnbous cupulae, laying in a row and alternating left and tight of center.

Other Behaviors

It tends to rest motionless on the bottom for long periods of time.  It does not respond to light (Green and Romero 1997).  It shows a wide range of agosnistic behaviors (Bechler 1983) and weak rheotaxic responses (Noltie and Wicks 2001).

Phylogenetic Relationships

This species is probably artificially composed unrelated (paraphyletic) populations due to its extensive horizontal distribution in karsts (Bergstrom et al. 1995).

Conservation Status

Vulnerable (VU D2) (World Conservation Monitoring Centre, WCMC). Alabama: Protected; Arkansas: Inventory element; Missouri: Watch; Oklahoma: Extirpated; Alabama: Threatened; Georgia: rare; Indiana: Endangered; Kentucky: Special concern; Tennessee: Deemed in need of management (Noltie and Wicks 2001).

Global Rank: G4 apparently secure.  The global rank of G4 is usually assigned to species that have been recorded from more than 100 localities.  Although this species is known from sufficient localities to merit the rank of G4, its position in cave ecosystems as a predator suggests a lower (G3) rank.

Missouri State Rank: S2/S3 imperiled/vulnerable; The state rank of S2 is typically assigned to species that have been recorded from between 6-20 localities. The state rank of S3 is assigned to species that have been recorded from between 21-100 localities.

Threats

Water pollution in recharge areas due to urbanization and suburban housing, municipal sewage treatment plants, mining, confined animal operations, and transportation routes may threaten water quality (Aley and Aley 1997).

Sedimentation is another serious threat because the habitat requirements of this species (see above).