Carabhydrus turaki, Hendrich & Watts, 2009

Hendrich, Lars & Watts, Chris H. S., 2009, Taxonomic revision of the Australian predaceous water beetle genus Carabhydrus Watts, 1978 (Col. Dytiscidae, Hydroporinae, Hydroporini), Zootaxa 2048 (1), pp. 1-30 : 24-25

Carabhydrus turaki sp.n.

( Figs 5 , 28 , 36, 37 )

Type locality: Head waters of Pappinbarra River , Werrikimbe Trail, Werrikimbe National Park .

Type material: Holotype: Female : “NSW EPA Survey MRHI HAST 09 Pappinbarra River u/s Field Study Centre 5/10/95 152.4182 31.2503 [Head waters of Pappinbarra River, Pappinbarra East Arm Road, Werrikimbe National Park, 220 m, NE NSW] Edge Eren Turak leg. EPA 10834”, “ Holotype Carabhydrus turaki sp. n. Hendrich & Watts des. 2008” [red printed label] ( AM).

Description: Measurements: Holotype: TL = 2.35 mm, TL-H = 2.1 mm, MW = 1.1 mm.

Color ( Fig. 5 ): Almost dark reddish brown to black, the front of clypeus, antennae, palpi and legs pale reddish brown. Pronotum black with narrow lateral reddish brown margin. Two large basal elytral marks extending to sides but not to suture, and a vague apical band of elytra reddish brown. Ventral surface black except epipleura and last three abdominal segments reddish brown.

Sculpture: Head anterior to dorsal impression with deep punctures separated by a distance about 1 ½ equal to their own diameters, and a few sparse, minute punctures; interspaces smooth and shiny, microreticulate along hind edge on a strip along small eyes, and in two shallow depressions medially from indistinct swellings above antennae.

Pronotum shining sparsely punctuate medially in front, denser on rest of surface but difficult to see because of many small wrinkles connecting punctures, microreticulation absent. Wrinkles transverse in basal half. Strongest between striae, fine and directed anteriorly or obliquely to outside near front ends of striae.

Elytron with dual irregular punctation similar to that of pronotum but more dense, surface somewhat uneven especially near middle where punctures are larger, near tip they are fine. Lateral part and apical half of elytra with fine microreticulation; epipleura simple, distally narrowed, disappears in distal fifth with dense, more or less contiguous punctures.

Ventral surface with punctures similar in size than those of dorsal surface, denser and more irregular with surfaces of sclerites irregularly rugose; punctures of metacoxal plate and sterna 1 and 2 not evidently larger than those elsewhere on ventral surface; metasternum medially and metacoxa between metacoxal lines sparsely and finely punctate. Legs with femora, tibiae, and dorsal surface of metatarsomeres 1–3 strongly punctate.

Structure: Head very broad, with cervical stria between posterior edge of eyes. Lateral margins of clypeus somewhat produced laterally above base of antenna; frontal fovea distinct, ovate; dorsal surface with a strong transverse impression between posterior margins of eyes; maxillary and labial palpi each with apical palpomere fusiform.

Pronotum slightly transverse, less sinuate and cordiform, at base same width as head. Basal half flat, anterior part curved down, especially near projecting anterior angles where there is a slight depression, parallel to rear margin of head. Lateral margin in dorsal aspect more or less evenly rounded; lateral bead sharply defined, narrow; basal margin slightly lobed medially; disc with a pair of broad and deep longitudinal impressions, each extending from apical third of disc to hind margin and strongly limited on outer side by a more or less carinate ridge, one large deep depression just behind centre of pronotum and of same size and form as longitudinal impressions, mesal margin less distinct; several additional shorter and more irregular rugae or impressions as well as elongate punctures along basal margin adjacent to the major impressions. Scutellum visible, short and broad.

Elytra together elongate-oval with point of maximum width near middle, sides converging basally; disc of each elytron with a medial and a sublateral, broad, deep and sharply defined longitudinal groove each bearing a row of serial punctures, and a less evidently defined lateral groove adjacent to lateral margin; medial and sublateral groove beginning approximately opposite basolateral impression of pronotum, sharply defined on basal three-fourths, becoming shallower apically.

Ventral surface, lateral portions of thorax and abdomen narrowed ventrally, medially forming a more or less flattened area comprising prosternal process, medial area of metasternum, intralinear space of metacoxae, and abdominal sterna medially. Prosternum with anterolateral pore well removed from anterior margin. Prosternal process hardly deflexed, grooved in middle, sides raised, oval. Metasternum largely in a vertical plane, prosternal process touches metasternum between mesocoxae. Metasternum medially flat, faintly raised anteriorly joined lines extend from between mesocoxae posteriorly, where they become indistinct. Metacoxal lines raised, first directed a little outward as usual but their front ends curved slightly medially. Metacoxal process flat, distally hardly sinuous, indistinctly notched in middle.

Legs long. Coxae and trochanters normal. Femora simple, metafemur shorter than others and much shorter than tibia. All femora largely visible from above. Profemur with anteroventral margin slightly emarginate subapically and fringed with a row of short, stout setae. Protibia with medially enlarged apical half, a regular row of very fine and short setae on inside below. Three basal tarsal segments enlarged, symmetrical, with adhesive hairs below and long fine hairs above. Protibia with medially enlarged apical half, a regular row of very fine short setae on inside below. Apex oblique on outside, with several spines. Normal spurs present. Three basal tarsal segments enlarged, symmetrical, with adhesive hairs below and long fine hairs above. Tarsal segment 4 minute, fifth slender, long, with equal slender claws. Mesotibia straight, inner face with long hairs. Pro- and mesotarsomeres 1–3 ovate; protarsomere 4 small, situated within emargination of tarsomere 3 but visible in dorsal aspect. Hind legs slender; metatibia straight, evenly broadened from base to apex, natatorial setae absent from ventral face in female, metatarsal claws equal.

Male: Unknown.

Etymology: The species is dedicated to the Australian limnologist and ecologist Dr Eren Turak (NSW Department of Environment and Climate Change, Sydney) who collected the only known specimen of the species.

Differential diagnosis: In colour and size C. turaki sp.n. resembles C. andreas but has a more flattened body, much better defined and very deep elytral grooves reminisent of those in C. mubboonus , a wider appearance than C. andreas due to the pronotum being less strongly cordiform and sinuate laterally, the pale elytral spots are less defined than in C. andreas and almost half of the elytra is covered by a fine microretulation which is absent in C. andreas .

Distribution: North-eastern New South Wales ( Fig. 28 ). Only known from the type locality. According to the geographical coordinates on the locality label most probably a head water stream of the Pappinbarra River in Werrikimbe National Park.

Habitat: A rheophilic species collected in a river with good riffle habitats with cobble (40%), boulder (20%) and pebble (15%) substratum and fringed by old growth forest ( Figs 36, 37 ). The width varied between 4 and 12 m and the oxygen level was high (dissolved oxygen 10.4 mg /l). No true macrophytes were present but a small amount of filamentous algae and a tiny amount of aquatic moss were observed in April 1996. The riparian vegetation was fairly dense with three distinct layers. The bottom layer was sedges, grasses and ferns dominated by Lomandra longifolia and bracken (Pretidium esculentum). The middle layer was shrubs and small trees (e.g Acacia sp. , Callicoma serratifolia and Ficus coronota ). The upper layer consisted of taller trees such as large acacias as well as some rainforest tree species such as Ceratopetalum apetalum , Ehretia acuminata and Syzygium australe ). There were some weeds such as Camphor laurel and wild tobacco (Turak in litt.).

Figures

FIGURES 5–9. Habitus of Carabhydrus. 5—Carabhydrus turaki sp.n. (holotype, female); 6—C. stephanieae (paratype); 7—C. mubboonus (female); 8—C. janmillerae sp.n. (paratype, female); 9—C. niger (female) (scale bar 1 mm) (Photos: L. Hendrich).

FIGURES 28–29. Distribution of the genus Carabhydrus in Australia.

FIGURES 36–39. Type localities of 36, 37—C. turaki sp.n., head waters of Pappinbarra River, Werrikimbe National Park in New South Wales (Photos: Natacha Waddell, April and October 1995); 38, 39—C. storeyi sp.n., Mary Creek at Maryfarms NE Queensland (Photos: C. Watts, December 2008).