Potamonautes johnstoni ( Miers, 1885 )

Reed, Sadie K. & Cumberlidge, Neil, 2006, Brachyura: Potamoidea: Potamonautidae, Platythelphusidae, Deckeniidae (), Zootaxa 1262 (1), pp. 1-139: 1-139

publication ID

http://doi.org/ 10.11646/zootaxa.1262.1.1

persistent identifier

http://treatment.plazi.org/id/039E87EB-FFB3-0363-7A69-ED54327DF9C3

treatment provided by

Felipe

scientific name

Potamonautes johnstoni ( Miers, 1885 )
status

 

4. Potamonautes johnstoni ( Miers, 1885)   (Figs. 31–40, 151–152, 176, plate IV)

Thelphusa depressa var. johnstoni Miers, 1885: 237–239   .

Telphusa hilgendorfi Pfeffer, 1889: 32   .

Potamon (Potamonautes) ambiguus Rathbun, 1904   : pl. 14, fig. 7; 1905: 171.

Potamon (Potamonautes) mrogoroensis   — Rathbun, 1905: 173 (not Hilgendorf, 1898).

Potamon (Potamonautes) Johnstoni   — Rathbun, 1905: 170.

Potamonautes johnstoni   — Balss, 1929: 343–344; 1936: 180–182, fig. 17; Cumberlidge, 1997: 580– 581; 1998: 200.

Potamonautes johnstoni   f. typical — Pesta, 1937: 157.

Potamon johnstoni   — Chace, 1942: 214.

Potamon (Potamonautes) hilgendorfi   — Rathbun, 1933: 256; 1935: 6; Chace, 1942: 186.

Potamonautes (Lirrangopotamonautes) johnstoni johnstoni   — Bott, 1955: 265–267: pl. XV, fig. 2a– d, fig. 36a, b.

Type material examined: TANZANIA: Thelphusa depressa var. johnstoni Miers, 1885   : Kilimanjaro, male type (cw 57, cl 40, ch 24.2, fw 16.2 mm) ( BMNH 1885.2). Potamon (Potamonautes) ambiguus ( Rathbun, 1905)   : female type, Kilimanjaro, Saumi River, 1,000 to 1,600 m asl ( USNM 30008). Holotype of Telphusa hilgendorfi Pfeffer, 1889   (subadult female, cw 20.8, cl 15.1, ch 7.2, fw 6.1 mm; ZMB 11377 View Materials ).

Additional material examined: TANZANIA: West Usambara Mountains, Garaya River near Dindila Factory , adult male (cw 71.6 mm), adult female (cw 84.1 mm), 5.ix.1964 (J. N. Raybould) ( NMU TRW1966.05)   ; south slopes of Kilimanjaro, Kondeni River near Marangu , adult male (cw 52.3 mm), 6.v.1966 (J. N. Raybould) ( NMU TRW1966.13)   ; 16 km east of Arusha, Usa River (tributary of Kikuletwa River, itself a tributary of the Pangani River ) male (cw 53 mm), female (cw 48.7 mm) 26.v.1966 (J. N. Raybould) ( NMU TRW1966.14)   ; Kibalwa, near Taveta, canal from Lumi River , subadult female (cw 46.5 mm), 1.ii.1967 (J. E. Hudson) ( NMU TRW1968.10)   ; Kibalwa, near Taveta, Canal from Lumi River , male (cw 53.5 mm), 1.ii.1967 (J. E. Hudson) ( NMU TRW1968.12)   ; East Usambara Mountains, Amani , male (cw 76.4 mm) 6.v.1966 (J. N. Raybould) ( NMU TRW1969.02)   ; East Usambara Mountains, Amani , subadult female (cw 64.6 mm), 2 males (cws 61.1, 62 mm), 1970 ( T. R. Williams) ( NMU TRW1970.01)   ; male (soft­shelled), 6.vii.1970 ( T. R. Williams) ( NMU 076.1970.1); East Usambara Mountains , Amani, male (cw 56.8 mm), 1970 ( T. R. Williams) ( NMU TRW1970.03)   ; East Usambara Mountains, Amani , subadult female (cw 48 mm), 27.iii.1971 ( NMU TRW1970.05)   ; canal near Taveta, male (cw 65.5 mm), adult female (cw 69.4 mm), 1971 ( NMU TRW1971.11)   ; Kilimanjaro area, Mue River, station 2, 3 males (cw 45.9 to cw 50.1 mm) ( NMU TRW EA62.67); East Usambara Mountains , Amani , Dodwe River , female with hatchlings (cw 77.9 mm), 1962 ( T. R. Williams ) ( NMU TRW­EA62.25); stream on Mount Kilimanjaro , 5 juvenile males (cw 21.9 to cw 38.9 mm), iv.1967 (J. E. Hudson) ( NMU TRW1968.11)   ; 3 juvenile males (cw 18.5 to cw 36.3 mm), 2 juvenile females (cw 25.5, 34.3 mm) ( NMU 03.29.1972.1–5); canal west of Taveta, 4 males (cw 48.9, 57 mm, 2 damaged) 2 females (cw 56.5 mm; 1 damaged), 2 juvenile females (cw 32.9, 33.2 mm) (J. E. Hudson) ( NMU 07.2001.c)   . KENYA: stream above Kibo , 3 males (cw 42 to cw 63.7 mm) (J. E. Hudson) ( NMU TRW1971.13)   ; stream above Kibo , 22 juveniles (J. E. Hudson) ( NMU TRW1971.14)   ; “Afrique Orientale” (either Boura [Taita] or Kilimanjaro ), male (cw 47.4 mm), 1904 (C. H. Alluaud) ( USNM 32297 View Materials )   ; Mount Mbolo , Taita, male, iv.1934 (A. Loveridge) ( USNM 70913 View Materials )   .

Diagnosis. Postfrontal crest sharp­edged distinct, complete; exorbital tooth small, low; epibranchial tooth small granule, anterolateral margin immediately behind epibranchial tooth smooth; ischium of third maxilliped with vertical sulcus; thoracic sternal sulcus s3/ s4 complete, deep; sternite s4 lacking raised marginal ridges at points where chelipeds articulate; episternal sulci s4/e4–s7/e7 all clearly marked; dactylus of major cheliped of adult males broad, curving but not arched; first carpal tooth on carpus of cheliped sharp spine; second carpal tooth sub­equal spine; medial inferior margin of merus of pereiopod 1 lined with teeth, lateral inferior margin granulated; distal meral tooth large, pointed; proximal half of terminal article of gonopod 1 straight, second half bending outward at 45° angle; lateral side of terminal article of gonopod 1 widened in middle by distinctly raised lateral fold forming long crest; medial fold small, low; base of terminal article concave at dorsal membrane; distal margin of subterminal segment at dorsal membrane u­shaped, medial, lateral sides equally high; dorsal membrane subcircular, narrowest at medial, lateral margins.

Size. Large, with an adult size range between cws 45–50 mm. The largest specimen examined was an adult female, cw 84.1 mm.

Type locality. Kilimanjaro, Tanzania   .

Distribution. Kenya and Tanzania.

Remarks. All specimens of P. johnstoni   were identified based on comparisons with detailed illustrations of the carapace, mouthparts, sternum, abdomen and gonopods of the male type specimen of T. depressa var. johnstoni Miers, 1885   (cw 57 mm) (BMNH 1885.2) from Kilimanjaro. Unfortunately, Calman (1913) used the same name to describe a specimen from the Ruwenzori Mountains in Uganda. Cumberlidge (1997, 1998) examined the type material of both of these taxa and concluded that the specimens from Kilimanjaro and the Ruwenzoris belong to two distinct species. The specimens from Kilimanjaro retain the name Potamonautes johnstoni Miers, 1885   by priority, while the type of Calman’s (1913) species from the Ruwenzoris corresponds to Potamonautes aloysiisabaudiae ( Nobili, 1906)   .

Bott (1955) synonymized P. johnstoni   with seven different taxa, but Cumberlidge (1997, 1998) found all of these synonymies to be questionable. The carapace, sternum, mandibles and cheliped of the type specimens of Telphusa reichardi Hilgendorf, 1898   (a subadult female, cw 33.8, cl 23.7, ch 11.4, fw 10 mm; ZMB 7463), Telphusa suprasulcata var. pseudoperlata Hilgendorf, 1898   (a subadult male, cw 32.1, cl 24.3, ch 9.9, fw 9.2 mm; ZMB 9348) and Telphusa mrogoroense Hilgendorf, 1898   (a subadult female, cw 20.8, cl 15.1, ch 7.2, fw 6.1 mm; ZMB 11377 View Materials ) were examined in the present study by NC. In each of these taxa, the characters correspond well with those of subadult specimens of P. suprasulcatus ( Hilgendorf, 1898)   and all are treated here as junior subjective synonyms of P. suprasulcatus   . However, the type of Telphusa hilgendorfi Hilgendorf, 1898   (a subadult female, cw 20.8, cl 15.1, ch 7.2, fw 6.1 mm; ZMB 11377 View Materials ) was found to correspond well with P. johnstoni   and is considered here to be a junior synonym of P. johnstoni   .

Bott (1955) also synonymized P. johnstoni   with Potamon (Potamonautes) unisulcatus Rathbun, 1933   and with Potamon (Potamonautes) montivagus Chace, 1953   . Comparison of P. johnstoni   to the types of P. (P.) unisulcatus   (an adult male, cw 33, cl 21, ch 9, fw 10 mm; MCZ 7678a) and of P. (P.) montivagus   (an adult male, cw 65.5, cl 44.2, ch 21.8, fw 16.6 mm; MCZ 12611 View Materials ) found the characters of the carapace, sternum, mandibles and cheliped to be unique in each taxon. Therefore, Bott’s (1955) opinion that P. (P.) unisulcatus   and P. (P.) montivagus   are junior subjective synonyms of P. johnstoni   is not accepted in the present work. Finally, Bott (1955) regarded Potamon (Potamonautes) ambiguus   to be a junior synonym of P. suprasulcatus   , but examination of the characters of the carapace, chelipeds and first gonopods of the type of P. (P.) ambiguus   (USNM 30008) support the conclusion that this taxon should properly be treated as a junior synonym of P. johnstoni ( Miers, 1885)   .

Natural history and conservation status. The conservation status of P. johnstoni   is categorized as vulnerable (VU) ( Table 4) because it has a narrow range of occurrence and a restricted area of occupancy that are both below the thresholds for vulnerable (VU) ( IUCN 2004). It is difficult to estimate the population status and trends of this species, but its population is estimated to be declining based on indirect measures such as lack of recent collections of specimens, a relatively poor representation in museum collections and increasing habitat disturbance associated with growing human populations in the region.

USNM

Smithsonian Institution, National Museum of Natural History

ZMB

Museum für Naturkunde Berlin (Zoological Collections)

T

Tavera, Department of Geology and Geophysics

R

Departamento de Geologia, Universidad de Chile

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Potamonautidae

Genus

Potamonautes

Loc

Potamonautes johnstoni ( Miers, 1885 )

Reed, Sadie K. & Cumberlidge, Neil 2006
2006
Loc

Potamonautes (Lirrangopotamonautes) johnstoni johnstoni

Bott, R. 1955: 265
1955
Loc

Potamon johnstoni

Chace, F. A. 1942: 214
1942
Loc

Potamonautes johnstoni

Pesta, O. 1937: 157
1937
Loc

Potamon (Potamonautes) hilgendorfi

Chace, F. A. 1942: 186
Rathbun, M. J. 1935: 6
Rathbun, M. J. 1933: 256
1933
Loc

Potamonautes johnstoni

Cumberlidge, N. 1998: 200
Cumberlidge, N. 1997: 580
Balss, H. 1936: 180
Balss, H. 1929: 343
1929
Loc

Potamon (Potamonautes) mrogoroensis

Rathbun, M. J. 1905: 173
1905
Loc

Potamon (Potamonautes)

Rathbun, M. J. 1905: 170
1905
Loc

Telphusa hilgendorfi

Pfeffer, G. 1889: 32
1889
Loc

Thelphusa depressa var. johnstoni

Miers, E. J. 1885: 239
1885