Potamonautes adeleae Bott, 1968

Cumberlidge, Neil, Ahles, Katelyn M. & Daniels, Savel R., 2021, Redescriptions of three species of freshwater crabs from Angola, southern Africa (Brachyura: Potamoidea: Potamonautidae), Zootaxa 5032 (4), pp. 516-532: 517-518

publication ID

https://doi.org/10.11646/zootaxa.5032.4.3

publication LSID

lsid:zoobank.org:pub:B91E6B10-5DF1-4963-98F2-883E6DBD25EB

persistent identifier

http://treatment.plazi.org/id/C7608796-6044-FFCC-6B83-FBEAFDC7FEC7

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scientific name

Potamonautes adeleae Bott, 1968
status

 

Potamonautes adeleae Bott, 1968  

Adele’s Freshwater Crab

( Figs. 1 View FIGURE 1 , 4A View FIGURE 4 , 5A, B, G, H View FIGURE 5 , 6A, D View FIGURE 6 , 7A View FIGURE 7 , 8 View FIGURE 8 )

Potamonautes (Lirrangopotamonautes) lirrangensis adeleae Bott, 1968: 168–169   , pl. I, figs. 1–4.

Potamonautes adeleae, Cumberlidge & Tavares 2006: 248–249   , 254–256, table 1; Cumberlidge 2008a: 1–7, fig. 1; Ng et al. 2008: 170.

Holotype. SMF 4444 View Materials . Adult male (CW 60, CL 45, CH 23, FW 17 mm), Angola, Province of Lunda Norte, Cuango River , Cafunfo (-8.808363, 17.97665), collector and date unrecorded. GoogleMaps  

Paratypes. SMF 4444 View Materials . Adult male (CW 55.3, CL 41.1, CH 17.8, FW 15.7 mm), Angola, Province of Lunda Norte, Cuango River , Cafunfo (-8.808363, 17.97665), collector and date unrecorded. Bott (1968) described this taxon from 38 specimens all from the same locality, and designated the remainder of these specimens (28 males and 9 females) as paratypes GoogleMaps   .

Rediagnosis. Carapace surface mostly smooth except for distinct fields of carinae at anterolateral corners; postfrontal crest distinct, complete, traversing entire carapace to meet anterolateral margins at epibranchial teeth; cervical grooves deep, long, ending just before reaching postfrontal crest; semicircular, urogastric, cardiac, branchial grooves all deep, distinct ( Fig. 1A View FIGURE 1 ). Exorbital tooth large, pointed, directed forward, outer margin lined by small granules; epibranchial tooth small, low, blunt; anterolateral margin lined by rounded denticles; postfrontal crest, suborbital margin, vertical sulcus on branchiostegite, all granulated ( Figs. 1A, B View FIGURE 1 ). Thoracic sternal suture S3/4 incomplete, separated centrally, comprising 2 shortened sutures that begin at sides of sternum, fade towards middle ( Fig. 1B View FIGURE 1 ). Third maxilliped exopod with long flagellum, ischium with distinct vertical sulcus ( Fig. 1B View FIGURE 1 ). Cheliped carpus inner margin with 2 large pointed teeth, distal tooth larger than proximal tooth ( Fig. 5H View FIGURE 5 ). Cheliped merus lower margin with conspicuous large pointed distal meral tooth ( Fig. 5G View FIGURE 5 ). G1 TA long ( TA /SS 0.54), midpoint angled outward at 64° to longitudinal axis of G1 SS, distal third tapering to pointed, slightly upcurved tip; G1 TA midsection widened by high mesial fold, lateral fold lower; deep longitudinal groove running along whole length of G1 TA between mesial, lateral folds ( Figs. 6A, D View FIGURE 6 ). G2 TA long, flagellum-like (G2 TA / SA 0.65) ( Fig. 7A View FIGURE 7 ). Large species, mature at CW 55 mm.

Redescription: Carapace moderate height ( CH /FW 1.13), width (CW/FW 3.5), length (CL/ FW 2.62). Surface of anterior carapace mostly smooth except for distinct fields of carinae at anterolateral corners; postfrontal crest distinct, complete, traversing entire carapace to meet anterolateral margins at epibranchial teeth; cervical grooves deep, long, ending just before postfrontal crest; semicircular, urogastric, cardiac, branchial grooves all deep, distinct; postfrontal crest, suborbital margin, vertical sulcus on branchiostegite, all granulated; epigastric crests separated by clear, short, forked mid-groove ( Fig. 1A View FIGURE 1 ). Exorbital tooth large, pointed, directed forward, outer margin granulated; epibranchial tooth small, low, blunt; anterolateral margin between exorbital, epibranchial teeth granulated, curving slightly outward, lacking intermediate tooth; anterolateral margin posterior to epibranchial tooth raised, lined by rounded denticles, posterior end curving inward, not continuous with posterolateral margin. Branchiostegite with distinct granulated vertical sulcus, subhepatic region heavily granulated, suborbital, pterygostomial regions smooth ( Figs. 1A, B View FIGURE 1 , 4A View FIGURE 4 ). Third maxilliped exopod with long flagellum, ischium with deep vertical sulcus ( Fig. 1A View FIGURE 1 ). Thoracic sternal sulcus S2/3 deep, completely traversing sternum; S3/4 incomplete, deep at sides, absent in middle, sides slanted inward toward anterior margin of sternopleonal cavity; thoracic episternal sulci S4/E4, S5/E5, S6/ E6, S7/E7 all obscure ( Fig. 1B View FIGURE 1 ).

Male pleon, telson together forming slim triangle, pleon edges slightly indented; telson triangular, apex round- ed, base broadest, sides outwardly sloping; pleomeres PL1–6 rectangular, wider than long, PL 6 longest, more than 1/2 as long as wide ( Fig. 1B View FIGURE 1 ); remaining pleomeres short, less than 1/3 as long as wide. G1 TA long (TA/SA 0.54), midpoint angled outward at 64° to longitudinal axis of G1 SA, distal 1/3 tapering to pointed, slightly upcurved tip; G1 TA midsection widened by high mesial fold, lateral fold lower; deep longitudinal groove running along whole length of G1 TA between mesial, lateral folds ( Figs. 6A, D View FIGURE 6 ); G1 SA distal dorsal side with conspicuous dorsal membrane widest at mesial margin, narrowest at lateral margin ( Fig. 5D View FIGURE 5 ). G2 TA long (G2 TA/SA 0.65), flagellum-like ( Fig. 7A View FIGURE 7 ). Adult size ranging from CW 55 to 60 mm.

Chela unequal, right (major) longer than left (minor) ( Fig. 5A View FIGURE 5 ). Fixed finger (pollex) of propodus, movable finger (dactylus) each with 2 to 3 large teeth interspersed with smaller teeth; dactylus straight, slim, not arched, tips of fingers touching enclosing long thin interspace when closed ( Figs. 5A, B View FIGURE 5 ); propodi of right, left chelae elongated (inferior margin 55.1 mm, 50.3 mm respectively), almost as long as CW (55.3 mm); palms of right, left chelae not enlarged (height 18.2 mm, 15.5 mm respectively). Cheliped carpus inner margin with large pointed distal tooth, smaller pointed proximal tooth ( Fig. 5H View FIGURE 5 ); cheliped merus lower margins both lined by large granules; distal meral tooth large, pointed; superior surface of cheliped merus granulated ( Fig. 5G View FIGURE 5 ). P2–5 slender, long. For additional characters and photographs of this species see Bott (1968: pl. 1, figs. 1–4).

Size. Large species, adult at CW 55.0 mm.

Type locality. Angola. Province of Lunda Norte, Cuango River, Cafunfo (-8.808363, 17.97665) ( Fig. 8 View FIGURE 8 ) GoogleMaps   .

Habitat. Potamonautes adeleae   is a large species that is endemic to Angola. It is known only from a single locality in the forested Lunda Norte Province. It was collected from the Cuango River, a northward-flowing tributary of the Congo River which is part of the central African region ( Fig. 8 View FIGURE 8 ).

Colour. The colour of living specimens is unknown, but specimens preserved in ethanol are light brown.

Distribution. This species is only known from a single locality in Angola in the Province of Lunda Norte, Cuango River, Cafunfo (-8.808363, 17.97665) ( Fig. 8 View FIGURE 8 ).

Conservation status. Potamonautes adeleae   was listed in the IUCN Red List of Threatened Species as Data Deficient ( Cumberlidge 2008a) because it is known to occur in just one locality and there is very little information available on its population trends, habitat, or threats. This makes it a rare species of high research interest. The diamond mines at Cafunfo have resulted in a great deal of habitat disturbance and pollution of the Cuango River, that may prove to be threats to this species.

Remarks. Bott (1968) described P. adeleae   as a subspecies of P. lirrangensis ( Rathbun, 1904)   from Liranga, Republique du Congo, in the middle Congo basin but Cumberlidge & Tavares (2006), Cumberlidge (2008c), and Ng et al. (2008) recognised P. adeleae   as a valid species. Cumberlidge & Tavares (2006) cited morphological differences between the adult male paratype of P. adeleae   from Angola and the dried adult female type of Potamon (Potamonautes) lirrangensis Rathbun, 1904   (CW 53.9 mm) which was photographed by Rathbun (1904: pl. XIV, fig. 8), and illustrated by Capart (1954: fig. 28). Potamon (Potamonautes) lirrangensis   was recently redescribed by Cumberlidge et al. (2021: figs. 1, 4A, 7A) as Potamonautes lirrangensis   s.s. who restricted that species to the type specimen from Liranga, Republique du Congo, in the middle Congo basin. Unfortunately, the fact that the female holotype of this species is poorly preserved excludes most of the taxonomic characters that are useful to distinguish between species. Despite this, differences in the anterolateral margin of P. adeleae   ( Fig. 1A, B View FIGURE 1 ) and P. lirrangenis   s.s. (cf. Cumberlidge et al., 2021: fig. 4A) can be used to separate these two taxa. Potamonautes adeleae   shares a number of characters (e.g., a complete postfrontal crest, a reduced epibranchial tooth, a granulated anterolateral margin, and the general form of the G1 TA) with species from the middle Congo River basin (such as P. dybowskii ( Rathbun, 1904))   , and the affinities of this Angolan species lie with the Congo basin fauna rather than with the southern African regional fauna.

TA

Timescale Adventures Research and Interpretive Center

SA

Museum national d'Histoire Naturelle, Laboratiore de Paleontologie

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Potamonautidae

Genus

Potamonautes

Loc

Potamonautes adeleae Bott, 1968

Cumberlidge, Neil, Ahles, Katelyn M. & Daniels, Savel R. 2021
2021
Loc

Potamonautes adeleae, Cumberlidge & Tavares 2006: 248–249

Cumberlidge, N. 2008: 1
Ng, P. K. L. & Guinot, D. & Davie, P. J. F. 2008: 170
Cumberlidge, N. & Tavares, M. 2006: 249
2006
Loc

Potamonautes (Lirrangopotamonautes) lirrangensis adeleae

Bott, R. 1968: 169
1968