Crepis sidneyi, Reverter-Gil, Oscar, Souto, Javier & Fernández-Pulpeiro, Eugenio, 2011

Reverter-Gil, Oscar, Souto, Javier & Fernández-Pulpeiro, Eugenio, 2011, Revision of the genus Crepis Jullien (Bryozoa: Cheilostomata) with description of a new genus and family and notes on Chlidoniidae, Zootaxa 2993, pp. 1-22 : 6-9

Crepis sidneyi n. sp.

( Figs 12–17 ; Tables 4, 5)

Crepis longipes: Harmer 1926: 318 (part), pl. 15, fig. 19. Crepis verticillata Harmer : Gordon 2009: 49.

Material examined. Holotype: NHMUK 1882.2.23.16, Port Darwin, Australia, donated by Lords of the Admiralty. Paratype: NHMUK 1929.9.13.82, New Harbour, Singapore, 6 fathoms, 28/02/1900, Dr R. Hanitsch, Ap. 10, 1900; Siboga Expedition. Monogr. 28, figured specimen, pl. 15, fig. 19.

Etymology. Named after Sir Sidney F. Harmer, who first studied the material ascribed here to this new species.

Description. Colony adnate, delicate, of branching uniserial series, growing on other erect bryozoans or hydroids. Autozooids with a distal oval dilatation, with rounded distal edge; tapering proximally and prolonged into a slender cauda of variable length, sometimes long, otherwise reduced or even absent. Lateral walls irregular in their basal contact with substratum; vertical or slightly sloping in middle part of zooid depending on substratum, with smooth exterior-walled (gymnocystal) calcification. Gymnocyst mostly reduced to the proximal cauda. Frontal area bordered by a thin, even rim. Cryptocyst smooth, highest proximally, depressed medially, then gently rising to form proximal border of opesia, which is straight or slightly concave. Opesia distal, semi-elliptical, as long as wide, occupying about one third of frontal area; operculum occupying its distal half.

Zooidal branching frequent, each autozooid giving rise to two lateral buds from the dilatation, their caudae at right angles to the parent zooid or distally deflected, depending on morphology of substratum. Spines and heterozooids absent. Ancestrula and ovicell unknown.

Remarks. This species was originally reported as C. longipes by Harmer (1926) from the shallow waters of Singapore, New Guinea, and north of Australia, and as C. verticillata by Gordon (2009) from Darwin. Harmer (1926) pointed out that, “In spite of the great difference in locality and depth I cannot distinguish these specimens from C. longipes , as described by Jullien”. We have examined part of the original material, kept in the NHMUK. The samples, as viewed by a binocular microscope, are indeed similar to C. longipes , but they exhibit a series of important differences from both this species and C. harmelini . Zooids and opesiae are much smaller in C. sidneyi n. sp.; the caudae are generally shorter and wider, though of variable length, being very long ( Figs 14, 17 ) or even practically non-existent ( Figs 13, 15, 16 ). The rim that surrounds the frontal surface is even, as is the cryptocyst that is depressed in its central area, rising slightly in its distal third; in C. longipes and C. harmelini the cryptocyst is flat and granular. New zooid branches in C. sidneyi are also budded from the middle area of the lateral walls of the dilated part of the zooid, but in some cases they can be more distally or proximally placed; they are generally curved distally when the substratum is narrow. Finally, C. sidneyi was collected between 6 and 29 m depth, usually on other bryozoa, while C. longipes and C. harmelini are found at great depths, generally on hard non-living substrata such as shells or stones.

Crepis sidneyi exhibits a degree of variability, related to the substrata over which it grows, adapting to the available space. A majority of the zooids in the material from Singapore (NHMUK 1929.9.13.82, paratype) have broader caudae, of variable length, the point of separation between the cauda and the dilated distal portion of the zooid been usually poorly defined. In this material ( Figs 14, 15 ) and in specimens from Darwin ( Fig. 17 ), the colonies exhibit a tendency to linearity, with zooids having long caudae, while the lateral zooids have very short, distally curved caudae. This mode of growth is suited to the erect filiform colonies on which they grow (e.g. hydroids and species of Nellia and Scrupocellaria ) and does not occur in a colony on a flat substratum (NHMHK 1882.2.23.16), also from Darwin. The basal surface of zooids in this colony is broader than the frontal surface, possibly because of the flatter substratum, whereas both surfaces have more or less the same width in the material collected by Gordon (2009) on erect bryozoans ( Figs 16, 17 ). Based on the measurements of zooidal characters and the shape of the cryptocyst, all this material appears to constitute the same species.

Two slides (NHMUK 1927.8.11.15) originally identified as C. longipes and originating from Amoy (now Xiamen), China, were also studied. The zooid illustrated in Fig. 18 has a proportionately long, thick cauda, similar to that in the material from Singapore. Owing to the type of slide mount it is difficult to determine fully the characters of the cryptocyst; we are not able to ascribe it with certainty to C. sidneyi or the other species reported here.

Silén’s (1941: 69, figs 83, 84) record of C. longipes from shallow waters of the Malacca Straits could correspond to C. sidneyi on the basis of geography, depth and substratum (a hydroid), however the original drawing does clearly establish the characters of this material, while in the original sample (SMNH 111278) we were not able to locate the colony of Crepis . The status of this record should be considered as doubtful.

Finally, the material reported by Harmer (1926) as C. longipes , from Seget, northern New Guinea (ZMA V.Bry. 1813), consists of only two zooids, which makes it difficult to decide on its status (see the following species).

Crepis sidneyi is known with certainty from Singapore at 11 m depth and from Darwin (northern Australia) between 6 and 29 m depth.

Mean SD Minimum Maximum N Frontal surface length 0.262 0.0167 0.218 0.281 13 Frontal surface width 0.141 0.0163 0.119 0.173 13 Opesia length 0.087 0.0083 0.074 0.102 13 Opesia width 0.079 0.0082 0.066 0.091 13 Opesia L/Zooid L 33.1 % 33.9 % 36.3 %

Cauda length 0.162 0.0516 0.081 0.234 12 Cauda width 0.034 0.0048 0.025 0.044 12

SD, Standard deviation; N, number of measurements.

Mean SD Minimum Maximum N Frontal surface length 0.241 0.0190 0.206 0.269 11 Frontal surface width 0.122 0.0093 0.105 0.137 11 Opesia length 0.094 0.0086 0.077 0.106 11 Opesia width 0.099 0.0113 0.081 0.117 11 Opesia L/Zooid L 39.3 % 37.4 % 39.4 %

Cauda width 0.054 0.0119 0.043 0.075 7

SD, Standard deviation; N, number of measurements.

Figures

FIGURES 12 – 17. Crepis sidneyi n. sp. 12, a colony on a flat substratum (NHMUK 1882.2. 23.16, holotype); 13, same, detail of branching; 14, autozooids showing long caudae (NHMUK 1929.9. 13.82, paratype); 15, same, central autozooids with long caudae and lateral autozooids with short caudae; 16, several autozooids, one of them lateral and without cauda (Darwin, photo by D. P. Gordon); 17, same, central autozooids with long caudae and lateral autozooids with short caudae (photo by D. P. Gordon).

FIGURES 18 – 22. 18, Crepis sp., Amoy, China (NHMUK 1927.8.11.15); 19, Crepis sinensis n. sp., view of colony (SMF 5429, holotype); 20, same, autozooid showing the distal cryptocystal curvature; 21 and 22, Crepis sp., autozooids, New Guinea (ZMA V. Bry. 1813).