8/8/2019 Redescription of Homaloptera ripleyi (Fowler, 1940) from Sumatra, Indonesia (Teleostei: Balitoridae)

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Redescription of Homaloptera ripleyi (Fowler, 1940) from Sumatra, Indonesia (Teleostei: Balitoridae)Gerhard Ott, Flensburg/Germany (gerhard-ott@sach-fach.de) for the International Loach Conference from 31. August to 3. September 2010 in Suchdol, Czech Republic

For 50 years the hillstream loachHomaloptera ripleyi was only known by asingle specimen collected by S. D. Ripley , eld representative o the Academy o Natural SciencesPhiladelphia during the George-Vanderbilt-Sumatra-Expedition19361939 on March 23, 1939.

The holotype was originally described by

H. W. Fowler in 1940 as Homalopterula ripleyi rom Sungai Goepang, GunungLeuser, Sumatra (Aceh), Indonesia.

omaloptera ripleyi , Holotype ANSP 68713hoto: Kyle LuckenbillNSP = Academy of Natural Sciences Natural History Museum Philadelphia, U.S.A

Several species o Homalopterawere collected 2003 by D. Dettmers and the author in North-Sumatra. One o these was identi ed asH. ripleyi .The present study aims to give a detailed description o thispoorly documented species, because the data o the reshdeposited material enables a more precise de nition o thespecies, removing some uncertainties (e.g. in measurementsand anatomical data).

enjamin, M. 1988. Mucochondroid (mucous connective) tissue s in the head o teleosts. Anatomy and Embryology 178, 461-474. Fowler, H. W. 1940. Zoological results o theeorge Vanderbilt Sumatran Expedition 1936-1939. Part II - The Fishes. Proceedings o the Academy o Natural Sciences Philadelphia 91, 369-398. Kottelat, M. 1990. Indochineseemacheilines. A revision o nemacheiline loaches (Pisces: Cyprini ormes) o Thailand, Burma, Laos, Cambodia and southern Vietnam. Dr. Friedrich P eil, Mnchen. Kottelat, M.998. Homaloptera yuwonoi,a new species o hillstream loach rom Borneo, with a new generic name orH. thamicola.Ichthyological Explorations o Freshwaters 9, 267-272. Tan, H. H.006. The Borneo Suckers. Revision o the torrent loaches o Borneo (Balitoridae:Gastromyzon, Neogastromyzon). Nat. Hist. Publications (Borneo), Kota Kinabalu, Sabah/Malaysia.

Many thanks to John Lundberg , curator and chair o ichthyology o the Academy o Natural SciencesPhiladelphia, U.S.A. and Mark S. Prez or their support and KyleLuckenbill or preparing photo- andradiographs o the type specimen. AxelZarske , Museum or Zoology, Ichthyological collection, Dresden,provides a urther radiograph. Critical comments by IngoSchindler , Berlin, Jrg Bohlen , Institute o

Animal Physiology and Genetics Libechov, Czech Republic, and an anonymous reviewer.

Ott, G. 2010. Redescription o Homaloptera ripleyi (Fowler , 1940) rom Sumatra, Indonesia (Teleostei: Balitoridae). Bulletin o Fish Biology 11 (1/2): 1-9. Received: 01.11.2009 Accepted: 01.12.2009 [in print]

Homaloptera ripleyi , ANSP 188908

The re-description is based on nine preserved and deposited specimens, onecleared and stained specimen (not deposited) and 14 living specimens, observedin the eld and in aquarium:Holotype: ANSP 68713, 51 mm TL, Indonesia, Sumatra, Province Aceh (Atjeh),river Goepang at Meloewak (locality 1 in map above) ANSP 188907, 1 specimen SL 39.3 mm, Indonesia, Sumatra, Province SumateraUtara, small nameless tributary to Sungai Bohorok, north o Bukit Lawang033301.4N - 098 0701.0E, 236 m asl. (locality 2) ANSP 188908, 4 specimens, SL 43.158.5mm, Indonesia, Sumatra, Province

Sumatera Utara, Tanah Karo County, Kampung Bassam northeast o Berastagi,southeast o Gunung Sibayak, 031127.1N 0983247.7 E 1391 m asl.MTD F 31804-31807, 4 specimens, SL 30.5 53.7 mm, Indonesia, Sumatra,Province Sumatera Utara, Tanah Karo County, Kampung Basam northeast o Berastagi, southeast o Gunung Sibayak, 031127.1N 0983247.7 E 1391 m asl.(locality 3)

Morphometric measurements ollow Tan (2006) and Kottelat (1990) with two modi cations: the length o snout and the length o caudal peduncle are measured asshown in the gure le t.

Used morphometric parameters (abbrevations in brackets):total length (TL), standard length (SL), preventral or prepelvic length (PVL), preanal length (PAL), predorsal length (PDL), head length (HL), snout length (SNL),caudal penduncle length (CPL), orbital diameter (OD), body depth at dorsal n origin (BDD), body depth at anus (BDA), caudal peduncle depth (CPD), interorbital width (IOW), head width (HW) and mouth width (MW). Relative morphometric data are calculated or BDD in SL, HL in SL, SNL in HL, OD in HL, OD in SNL,OD in IOW, IOW in HL and MW in HL.

Meristic data taken are counts o scales, n rays and vertebrae. Scales in lateral line (SLL) counts pored scales. Fin ray counts or pectoral, ventral (pelvic), dorsal andanal ns are given in roman numerals or simple (unbranched), rays and arabic numerals or branched rays. Counts or the vertebrae are taken rom radiographs o the holotype, another deposited specimen (MTD F 31804) and one cleared and stained specimen (in care o the author). Counts exclude the Weberian apparatus, butincludes the urostyle.

Diagnosis:

Homaloptera ripleyi di ers rom its congenersby the combination o the ollowingcharacters: eight to ten saddle like blotches onthe dorsal side o body not reaching the lateralline; ventral side completely scaleless; obliquely truncate caudal n, upper lobe more or lessdistinct slightly longer than lower lobe; aprominent curved shape o jaws, especially thelower jaw; ; dorsal- n origin just posterior toventral- n origin; 72-78 scales in lateral line.

Homaloptera ripleyi belongs in accordance withKottelat (1998) to a group o Homaloptera rom Sumatra (Homalopterula-group), including the speciesH. gymnogaster, heterolepis, ripleyi, ulmeri and vanderbilti , preli-minary characterized by a more cylindrical than compressed body, a relatively wide mouth, shorter paired ns than otherHomalopteraand a truncate or only slightly emarginate caudal n.Homaloptera ripleyi is currently nown only rom northern Sumatra, Indonesia. Until the likely polyphyletic lineage o Homalopteras.l. with several groups is better studied and understood, this species is treated asHomalopterahere. The histology o thessue especially on the jaw bones o H. ripleyi needs urther investigation.

Morphometric parameters shown in le t table match in all o the teen parameters with the holotype based onata in %SL and do not di er more than -1,7% to +2,6%. The range o the relative morphometric parametersrom right table match with the data o the rst description, except BDD in SL; that is due to the act that it isot clear where body depth was measured by Fowler (1940).

In a cleared and stained specimen the tissue on the jaw bones macerated away. One assumption is, that the outer shape o the jaws is ormed by achondroid tissue. In living or resh preserved specimens the jaws show a considerable elasticity and pearly bluish color.Benjamin (1988) has shown that in the balitorid shPseudogastromyzon cheni such tissues provide the jaws o bottom-dwelling algal eaters withfexible support.

The bones of the jaws in a cleared specimen (20 ) a : lateral view. b : dorsal view. c: ventral view

Homaloptera ripleyi , Holotype ANSP 68713Radiograph: Kyle Luckenbill

owler (1940) based the discrimination o his new enus Homalopterulawith H. ripleyi as type specieschiefy by the peculiar shape o its jaws. This characters shown in a small line drawing inFowler s originalescription; here shown as photograph.

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ntroduction

Material & Methods

Results

Conclusions

Literature (cited here, complete list in published paper) Acknowledgements

Further informations