Altiverruca longimandible, Chan, Benny K. K., Prabowo, Romanus Edy & Lee, Kwen-Shen, 2010

Chan, Benny K. K., Prabowo, Romanus Edy & Lee, Kwen-Shen, 2010, North West Pacific deep-sea barnacles (Cirripedia, Thoracica) collected by the TAIWAN expeditions, with descriptions of two new species, Zootaxa 2405, pp. 1-47 : 28

Altiverruca longimandible sp. nov.

Figures 2 D, 19, 20

Material examined. Holotype: ASIZCR 0 0 0 224, 1 specimen, Stn. CP375 (24º16.240’N, 122º11.720’E, 27 Aug. 2006, depth: 2216–2497 m), BD 9.78 mm. Paratype: NMNS-6006-003, 2 specimens, locality same as holotype, BD 8.2–9.8 mm.

Diagnosis. Altiverruca with single interlock between rostrum and carina, movable tergum interlocking with movable scutum by 3 main ribs; lower margin of mandible long, smooth, naked; caudal appendage long, 1/2 length of cirrus VI.

Description. Shell white, some individuals covered by dark brown coating ( Figs 2 D, 20A); apices of rostrum and carina marginal, produced, curved outwards ( Figs 2 D, 20A); rostrum and carina interlocking by 1 major rib; rostrum without secondary ridges directed towards tergal base ( Figs 2 D, 20A); movable tergum quadrangular, interlocking with movable scutum by 3 main ribs; movable scutum triangular ( Figs 2 D, 20A). Maxilla bilobed, dense, shorter setae clustered on lobes, long setae along superior margin ( Fig. 19 A); maxillule with wide notch, basal region of cutting edge expanded ( Fig. 19 B); 2 large, robust, cuspidate setae above notch, ~ 10 fine, cuspidate setae in notch, 8 large, cuspidate setae below notch ( Fig. 19 B); mandible elongated, with 3 teeth, equally spaced, lower margin very long, smooth, naked, inferior angle blunt, minutely pectinated ( Figs 19 C, E); mandibular palp elongated, setae along superior margin ( Fig. 19 D); labrum not concave, cutting edge straight, with numerous fine teeth ( Fig. 19 F). Cirrus I with rami unequal, outer ramus antenniform, 24-segmented, inner ramus short, 10-segmented ( Fig. 20 B); cirrus II with rami unequal, outer ramus antenniform, 21-segmented, inner ramus short, 10-segmented, with dense setae ( Fig. 20 C); cirri III–VI similar, rami subequal, long, slender; cirrus III with outer ramus 28-segmented, inner ramus 22-segmented; cirrus IV with outer ramus 32-segmented, inner ramus 34-segmented; cirrus V with outer ramus 27- segmented, inner ramus 30-segmented; cirrus VI with outer ramus 33-segmented, inner ramus 33-segmented ( Figs 20 D, E, F, G); caudal appendage long, 1/2 length of cirrus VI, 32-segmented ( Fig. 20 G).

Etymology. The species is named with respect to the long, lower margin of the mandible. The name of this species is treated as a noun in apposition.

Distribution. Presently known only from the type locality.

Remarks. In the present study, Altiverruca longimandible sp. nov. was recorded in the eastern waters of Taiwan. From external shell morphology, Altiverruca longimandible sp. nov. is similar to A. navicula ( Hoek, 1913) in having the apices of the rostrum and carina produced, the rostrum and carina interlocking with 1 rib and the movable scutum and tergum interlocking by several strong ribs. The mandible of A. longimandible sp. nov., however, has a very long, smooth, fragile lower margin that is devoid of setae, terminating at the blunt inferior angle, whilst that of A. navicula has a pectinated lower margin. Buckeridge (1994, 1997) reported that variation in mandible morphology may occur in A. navicula . In the present study, dissection of three specimens of A. longimandible sp. nov. revealed similar mandible morphology, suggesting that morphological variation of the mandible is not obvious in this species.

The mandible of Altiverruca vitrea Zevina, 1988 has a relatively long lower margin compared to other species, but it bears two teeth, whereas Altiverruca longimandible sp. nov. has three. No other barnacles have been reported to have such an exceptionally long lower margin ( Zevina, 1987, 1988, 1993; Buckeridge, 1994; Young, 1998, 2002) and, therefore, this species is considered new to science.

Figures

FIGURE 2. Taiwanese deep-sea barnacles (right side view on A – C, top view for D – I). A. Annandaleum japonicum biramosum, B. Litoscalpellum spinosus sp. nov., C. Scalpellum stearnsii, D. Altiverruca longimandible sp. nov., E. Altiverruca navicula, F. Metaverruca defayeae, G. Metaverruca recta, H. Rostratoverruca krugeri, I. Hexelasma velutinum.

FIGURE 19. Altiverruca longimandible sp. nov. A. Maxilla, B. Maxillule, C. Mandible, D. Mandibular palp, E. Lower margin of mandible, F. Labrum, insert showing fine teeth at cutting edge. Scale bars in µm.

FIGURE 20. Altiverruca longimandible sp. nov. A. External view of the whole specimen, B. Cirrus I, C. Cirrus II, D. Cirrus III, E. Cirrus IV, F. Cirrus V, G. Cirrus VI, showing caudal appendage. Scale bars in mm.